Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications

Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications

Koungmin RyuAdvisor Prof Chongwu Zhou

Ming Hsieh Dept of Electrical EngineeringViterbi School of Engineering

University of Southern Californiahttpnanolabuscedu

Funded by SRC NSF Intel NASA DARPA NIH Whittier

My Research

Nanoelectronicsbull Nanoscale transistors bull Nanoscale memoriesbull Circuits

Nanobiotechnologybull Biosensingbull Nano therapybull Drug delivery

Nano Materials

bull Carbon nanotubesbull NanowiresbullGraphene

oxLDLantibodyElectrode

PEIPEGNanowireNanotube

Si Substrate

SiO2

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Original MotivationMoorersquos Law

Original MotivationMoorersquos Law

1950 1970 1990 2010 2030

1 m

1 cm

Year

VLSI

Integratedcircuits

Transistor

Vacuum valves

Molecular dimensions

1 μm

10 nm

1 Α

Device size

From Intel

Si Substrate

Metal Gate

High-kTri-Gate

S

G

D

III-V

S

Carbon Nanotube FET

50 nm35 nm

30 nm

SiGe SD

Strained Silicon

Future options subject to research amp change

SiGe SD

Strained Silicon

90 nm65 nm

45 nm32 nm

20032005

20072009

2011+

Technology Generation

Source Intel

20 nm 10 nm

5 nm5 nm

5 nm

Nanowire

Manufacturing Development Research

Transistor Research

Research OptionsHigh-K amp Metal GateNon-planar TrigateIII-V CNT NW

CNT is a tubular form of carbon with diameter as small as 1 nm Length few nm to cm

CNT is configurationally equivalent to a two dimensional graphenesheet rolled into a tube

CNT exhibits1 Carrier mobility ~ 100000 cm2Vs2 Youngrsquos modulus over 1 Tera

Pascal as stiff as diamond3 Tensile strength ~ 200 GPa

Zigzag

Armchair

Chiral

MOLECULAR STRUCTUREMOLECULAR STRUCTURE

CNT can be metallic or semiconducting depending on chirality

Benchmarking CNT FETsBenchmarking CNT FETs

1

10

100

1000

10000

100000

130 90 65 45 22

Technology Node (nm)

Nor

mal

ized

FO

A

26X25X

28X 27X

Intrinsic CNT

MOS CNT FET

Band-edge SB CNTMidgap SB CNT

5000X

60X

50X20X

Si MOSFET

Source Ali Keshavarzi Intel

Nanotube Transistor ResearchNanotube Transistor ResearchGate

8nm HfO2

SiO2

p++ Si

PdPd CNT

Javey et al Nano Letters 4 1319 2004Delft Tans et al Nature 393 49 1998

Many people have studied individual nanotube transistors however the challenge is to integrate nanotube devices

Many people have studied individual nanotube transistors however the challenge is to integrate nanotube devices

Appenzeller et al PRL 93 19 2005

Drain

SourceGate

DrainSourceGate

Sapphire Substrate

GateOxide

Liu et al Nano Letters 6 34 2006

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes

Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes

SiSiO2

PMMA

Catalyst

CH4nanotube

Catalyst island

900 ordmC900 ordmC

metal electrode

H Dai et al Nature 395 878 (1998)

Infrastructure Nanotube CVD Generation IInfrastructure Nanotube CVD Generation I

1 μm

1 μm

26 nm in diameter

10 nm in diameter

High-quality nanotubes can be grown at specific positions

-60

-50

-40

-30

-20

-10

0

I DS(

nA)

-10-08-06-04-0200VDS(V)

Vg -4 V

0 V

2 V

6 V

Nanotube transistor can be easily produced

Si back gate

SiO2

S D

Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter

Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter

Carbon Nanotube Field-Effect Inverters X Liu R Lee J Han C Zhou Appl Phys Lett 79 3329 (2001)

One of the first integrated systems made of carbon nanotubes

Si back gate

K

Vin

Vout

VDD GND

p-type CNT n-type CNT

60

40

20

0

I DS(

nA)

-4 -2 0 2 4Vg(V)

VDS=10 mV

P type MOSFET12

8

4

0

I DS (

nA)

-4 -2 0 2 4Vg (V)

VDS=10 mV

N type MOSFET25

20

15

10

05

00

Vou

t(V)

252015100500Vin(V)

VDD=29 V

Vin Vout

0 V

VDD

p

n

Integrated Nanotube SystemsRing Oscillators Demonstrated by Avouris et al

Integrated Nanotube SystemsRing Oscillators Demonstrated by Avouris et al

Ph Avouris et al Science 311 1735 (2006)

Is there a way to assemble large quantities of nanotube devices

State-of-the-art of nanotube integration

Aligned Nanotubes for Devices and Circuits Aligned Nanotubes for Devices and Circuits

-- Project Mission Project Mission We want to tackle the challenging issue of We want to tackle the challenging issue of nanotube nanotube assembly and integrationassembly and integration

We want to grow carbon nanotubes withWe want to grow carbon nanotubes withControlled orientation (achieved by using Controlled orientation (achieved by using sapphire and quartz) sapphire and quartz) Controlled position (achieved) Controlled position (achieved) Controlled density (achieved) Controlled density (achieved) Controlled diameter (ongoing)Controlled diameter (ongoing)Controlled Controlled chiralitychirality (ongoing)(ongoing)

-- Our Approach Our Approach A novel nanotubeA novel nanotube--onon--insulator (NOI) insulator (NOI) approach based on approach based on aligned nanotubesaligned nanotubes for for integrated nanotube circuitsintegrated nanotube circuits Nanotube

devicesNanotube

circuits

Quartz SubstrateCatalyst Particle

Quartz Substrate

Nanotube

One of the first to grow aligned nanotubes on sapphireOne of the first to grow aligned nanotubes on sapphireJ of Am Chem Soc 127 5294 J of Am Chem Soc 127 5294 -- 5295 (2005) 5295 (2005)

The first to make aligned nanotube transistorsThe first to make aligned nanotube transistorsNano Letters 6 34Nano Letters 6 34--39 (2006)39 (2006)Reported by Reported by Scientific AmericanScientific American (April 2006 P16) (April 2006 P16)

The first to demonstrate waferThe first to demonstrate wafer--scale processing of aligned scale processing of aligned nanotube devices and circuitsnanotube devices and circuits

Logic circuits (CMOS inverter NAND NOR)Logic circuits (CMOS inverter NAND NOR)

The first to make transparent nanotube devicesThe first to make transparent nanotube devicesACS Nano in press (2008)ACS Nano in press (2008)

Chip

1

2

3

4

5

Our Achievements on Aligned Single-Walled NanotubesOur Achievements on Aligned SingleOur Achievements on Aligned Single--Walled NanotubesWalled Nanotubes

Synthesis of Aligned Nanotubes on Sapphire QuartzSynthesis of Aligned Nanotubes on Sapphire Quartz

Gas in

Gas out

Sapphire with catalyst

Substrate Sapphire quartzCatalyst FerritinTemperature 900degCGas flow rate

CH4 2000 sccmC2H4 10 sccmH2 800 sccm

Generation IIFull Wafer Production

Generation IIFull Wafer Production

50 μm

2 0

1 5

1 0

5N

umbe

r

2 01 0D iam e te r (nm)500 nm

134 plusmn 030 nm

1 All nanotubes grow normal to the c axis on a-plane sapphire2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin11 All nanotubes grow normal to the c axis on aAll nanotubes grow normal to the c axis on a--plane sapphireplane sapphire2 Narrow diameter distribution of 2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin

c axis

Aligned Nanotubes Grown on a-Plane SapphireAligned Nanotubes Grown on a-Plane Sapphire

Zhou et al JACS 127 5294 (2005)

Zhou Zhou et alet al Nano Letters Nano Letters (2006)(2006)(Top ten hot articles in 2006)

High density SWNTsUp to 40 nanotubes μmInter-nanotube spacing ~ 25 nm

Low density SWNTs

Control of Nanotube DensityControl of Nanotube Density

Zhou et al JACS 127 5294 (2005) Zhou Zhou et alet al Nano Letters (2006) Nano Letters (2006)

a-plane

Red spheres oxygen atomsBlue spheres aluminum atomsPurple plane a-plane orientation

Hypothetic Schematic Diagram of SWNT on a-Plane SapphireHypothetic Schematic Diagram of SWNT on a-Plane Sapphire

Calculation of Lennard-Jones Potential Calculation of Lennard-Jones Potential

sumsum⎥⎥⎥

⎦

⎤

⎢⎢⎢

⎣

⎡

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

minusminus⎟

⎟

⎠

⎞

⎜⎜

⎝

⎛

minus+

⎥⎥

⎦

⎤

⎢⎢

⎣

⎡

⎟⎟⎠

⎞⎜⎜⎝

⎛

minusminus⎟

⎟⎠

⎞⎜⎜⎝

⎛

minus=

j j

CAl

j

CAlCAl

i i

CO

i

COCO rrrrrrrr

rU

612612

44)( vvvvvvvvv σσ

εσσ

ε

a carbon atom and oxygen atoms in sapphire

a carbon atom and oxygen atoms in sapphire

a carbon atom and Al atoms in sapphire

a carbon atom and Al atoms in sapphire

Interaction between

Interaction between

C-plane C-plane a-plane a-plane

Potential wellPotential wellZhou Zhou et alet al JPCC JPCC 112 15929 (200(20088))

Synthesis of Nanotubes with Controlled Orientations and Positions

Synthesis of Nanotubes with Controlled Orientations and Positions

Catalyst

Photo Resist

QuartzSapphire

Catalyst Island

Aligned NanotubesMetal Electrode

SD

G

Dielectric Layer

3-10 nanotubes microm

Aligned Nanotubes on Quartz Using Patterned CatalystAligned Nanotubes on Quartz Using Patterned Catalystcatalyst

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

(a)

Poly Si Gate

Gate Oxide

SourceDrain Electrode

(b)

NanotubeGate Dielectric

Gate

SourceDrain Electrode

Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)

Comparison between SiliconComparison between Silicon--onon--insulator (SOI) and insulator (SOI) and NanotubeNanotube--onon--Insulator (NOI)Insulator (NOI)

SOISOISOI NOINOINOI

Common Features1 Active material (Si or SWNT) is all over the surface2 Many devices can be patterned anywhere on the substrate3 Unwanted silicon or SWNTs can be removed via etching4 SOI and NOI offer minimized parasitic capacitance faster switching speed

and lower dynamic power consumption

Common FeaturesCommon Features11 Active material (Si or SWNT) is all over the surfaceActive material (Si or SWNT) is all over the surface22 Many devices can be patterned anywhere on the substrateMany devices can be patterned anywhere on the substrate33 Unwanted silicon or Unwanted silicon or SWNTsSWNTs can be removed via etchingcan be removed via etching44 SOI and NOI offer minimized parasitic capacitance faster switchSOI and NOI offer minimized parasitic capacitance faster switching speed ing speed

and lower dynamic power consumptionand lower dynamic power consumption Zhou et al Nano Letters (2006)

a-Sapphire

Wafer-Scale Aligned Nanotube SynthesisWafer-Scale Aligned Nanotube Synthesis

1200

1000

800

600

400

200

Tem

pera

ture

200150100500

Time (min)

Growth Annealing

Key meticulous temperature control amp uniform growth

1μm

Quartz 1000

800

600

400

200Tem

pera

ture

6004002000

Time (min)

Growth Annealing

1μm

4 inch substrate

Gas in

Gas out

Quartz or Sapphire with patterned

catalyst

9 feet-long growth furnace with three-zone

Wafer-Scale CNT TransferWafer-Scale CNT TransferTransfer fullTransfer full--wafer of wafer of CNTsCNTs from quartz growth substrate to SiOfrom quartz growth substrate to SiO22Si fabrication Si fabrication

substrate substrate allows largeallows large--scale integrationscale integration

Nano Lett 9 189ndash197 20094

Wafer-Scale Aligned Nanotube Device FabricationWafer-Scale Aligned Nanotube Device Fabrication

Back-Gated Submicron TransistorsBack-Gated Submicron Transistors

Back-gated transistors

1 microm

L = 1 microm

1 microm

L = 075 microm

1 microm

L = 05 microm

I-Vg curves Channel length dependence

-120

-100

-80

-60

-40

-20

0

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

-60

-40

-20

0

I ds (μ

Α)

-1500Vds (V)

-1 V

-08 V

-06 V

-04 V

-02 V

Vg from -8V to 8V

15

10

05

I ds (m

A)

-10 -5 0 5 10Vg (V)

L = 05 microm L = 075 microm L = 1 microm L = 2 microm L = 5 microm L = 10 microm L = 20 microm

80

60

40

20

gm

(μ S

)

5 6 7 81

2 3 4 5 6 7 810

2

L(μm)

2

4

6810-6

2

4

6810-5

I DW

(mA

microm

) gm

Ion Ioff

Top-gated transistors

075 μmG

S

D

Al2O3

15

10

5

0

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

10-8

10-7

10-6

10-5

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

15

10

5

0

-5

-10

-15

I ds (μ

Α)

-10 -05 00 05 10Vds (V)

I-Vg curves I-Vds curves

Top-Gated Submicron TransistorsTop-Gated Submicron Transistors

N-type nanotube transistorsN-type nanotube transistorsHydrazine(NHydrazine(N22HH44) doping) doping

12

10

08

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds =01 V Vds =03 V Vds =05 V Vds =07 V Vds =09 V Vds =11 V

Before

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds=01 VVds=03 VVds=05VVds=07 VVds=09 VVds=11 V

After

Gain asymp54

10

08

06

04

02

00

Vou

t (V)

50454035302520

Vin (V)

6

5

4

3

2

1

0

I (nA)

Vout

I

Inverter

Gain =54

K doping

10

8

6

4

2

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

Before K doping After K doping

Gain asymp 5

p-type

n-type

15

10

05

00V

out (

V)

252015100500

Vin (V)

Gain=5

Potassium Doping and CMOS InverterPotassium Doping and CMOS Inverter

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

CMOS NAND amp NORCMOS NAND amp NORIndividual back-gated

NOR NAND

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

10 μm 10 μm10 μm

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

My Research

Nanoelectronicsbull Nanoscale transistors bull Nanoscale memoriesbull Circuits

Nanobiotechnologybull Biosensingbull Nano therapybull Drug delivery

Nano Materials

bull Carbon nanotubesbull NanowiresbullGraphene

oxLDLantibodyElectrode

PEIPEGNanowireNanotube

Si Substrate

SiO2

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Original MotivationMoorersquos Law

Original MotivationMoorersquos Law

1950 1970 1990 2010 2030

1 m

1 cm

Year

VLSI

Integratedcircuits

Transistor

Vacuum valves

Molecular dimensions

1 μm

10 nm

1 Α

Device size

From Intel

Si Substrate

Metal Gate

High-kTri-Gate

S

G

D

III-V

S

Carbon Nanotube FET

50 nm35 nm

30 nm

SiGe SD

Strained Silicon

Future options subject to research amp change

SiGe SD

Strained Silicon

90 nm65 nm

45 nm32 nm

20032005

20072009

2011+

Technology Generation

Source Intel

20 nm 10 nm

5 nm5 nm

5 nm

Nanowire

Manufacturing Development Research

Transistor Research

Research OptionsHigh-K amp Metal GateNon-planar TrigateIII-V CNT NW

CNT is a tubular form of carbon with diameter as small as 1 nm Length few nm to cm

CNT is configurationally equivalent to a two dimensional graphenesheet rolled into a tube

CNT exhibits1 Carrier mobility ~ 100000 cm2Vs2 Youngrsquos modulus over 1 Tera

Pascal as stiff as diamond3 Tensile strength ~ 200 GPa

Zigzag

Armchair

Chiral

MOLECULAR STRUCTUREMOLECULAR STRUCTURE

CNT can be metallic or semiconducting depending on chirality

Benchmarking CNT FETsBenchmarking CNT FETs

1

10

100

1000

10000

100000

130 90 65 45 22

Technology Node (nm)

Nor

mal

ized

FO

A

26X25X

28X 27X

Intrinsic CNT

MOS CNT FET

Band-edge SB CNTMidgap SB CNT

5000X

60X

50X20X

Si MOSFET

Source Ali Keshavarzi Intel

Nanotube Transistor ResearchNanotube Transistor ResearchGate

8nm HfO2

SiO2

p++ Si

PdPd CNT

Javey et al Nano Letters 4 1319 2004Delft Tans et al Nature 393 49 1998

Many people have studied individual nanotube transistors however the challenge is to integrate nanotube devices

Many people have studied individual nanotube transistors however the challenge is to integrate nanotube devices

Appenzeller et al PRL 93 19 2005

Drain

SourceGate

DrainSourceGate

Sapphire Substrate

GateOxide

Liu et al Nano Letters 6 34 2006

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes

Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes

SiSiO2

PMMA

Catalyst

CH4nanotube

Catalyst island

900 ordmC900 ordmC

metal electrode

H Dai et al Nature 395 878 (1998)

Infrastructure Nanotube CVD Generation IInfrastructure Nanotube CVD Generation I

1 μm

1 μm

26 nm in diameter

10 nm in diameter

High-quality nanotubes can be grown at specific positions

-60

-50

-40

-30

-20

-10

0

I DS(

nA)

-10-08-06-04-0200VDS(V)

Vg -4 V

0 V

2 V

6 V

Nanotube transistor can be easily produced

Si back gate

SiO2

S D

Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter

Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter

Carbon Nanotube Field-Effect Inverters X Liu R Lee J Han C Zhou Appl Phys Lett 79 3329 (2001)

One of the first integrated systems made of carbon nanotubes

Si back gate

K

Vin

Vout

VDD GND

p-type CNT n-type CNT

60

40

20

0

I DS(

nA)

-4 -2 0 2 4Vg(V)

VDS=10 mV

P type MOSFET12

8

4

0

I DS (

nA)

-4 -2 0 2 4Vg (V)

VDS=10 mV

N type MOSFET25

20

15

10

05

00

Vou

t(V)

252015100500Vin(V)

VDD=29 V

Vin Vout

0 V

VDD

p

n

Integrated Nanotube SystemsRing Oscillators Demonstrated by Avouris et al

Integrated Nanotube SystemsRing Oscillators Demonstrated by Avouris et al

Ph Avouris et al Science 311 1735 (2006)

Is there a way to assemble large quantities of nanotube devices

State-of-the-art of nanotube integration

Aligned Nanotubes for Devices and Circuits Aligned Nanotubes for Devices and Circuits

-- Project Mission Project Mission We want to tackle the challenging issue of We want to tackle the challenging issue of nanotube nanotube assembly and integrationassembly and integration

We want to grow carbon nanotubes withWe want to grow carbon nanotubes withControlled orientation (achieved by using Controlled orientation (achieved by using sapphire and quartz) sapphire and quartz) Controlled position (achieved) Controlled position (achieved) Controlled density (achieved) Controlled density (achieved) Controlled diameter (ongoing)Controlled diameter (ongoing)Controlled Controlled chiralitychirality (ongoing)(ongoing)

-- Our Approach Our Approach A novel nanotubeA novel nanotube--onon--insulator (NOI) insulator (NOI) approach based on approach based on aligned nanotubesaligned nanotubes for for integrated nanotube circuitsintegrated nanotube circuits Nanotube

devicesNanotube

circuits

Quartz SubstrateCatalyst Particle

Quartz Substrate

Nanotube

One of the first to grow aligned nanotubes on sapphireOne of the first to grow aligned nanotubes on sapphireJ of Am Chem Soc 127 5294 J of Am Chem Soc 127 5294 -- 5295 (2005) 5295 (2005)

The first to make aligned nanotube transistorsThe first to make aligned nanotube transistorsNano Letters 6 34Nano Letters 6 34--39 (2006)39 (2006)Reported by Reported by Scientific AmericanScientific American (April 2006 P16) (April 2006 P16)

The first to demonstrate waferThe first to demonstrate wafer--scale processing of aligned scale processing of aligned nanotube devices and circuitsnanotube devices and circuits

Logic circuits (CMOS inverter NAND NOR)Logic circuits (CMOS inverter NAND NOR)

The first to make transparent nanotube devicesThe first to make transparent nanotube devicesACS Nano in press (2008)ACS Nano in press (2008)

Chip

1

2

3

4

5

Our Achievements on Aligned Single-Walled NanotubesOur Achievements on Aligned SingleOur Achievements on Aligned Single--Walled NanotubesWalled Nanotubes

Synthesis of Aligned Nanotubes on Sapphire QuartzSynthesis of Aligned Nanotubes on Sapphire Quartz

Gas in

Gas out

Sapphire with catalyst

Substrate Sapphire quartzCatalyst FerritinTemperature 900degCGas flow rate

CH4 2000 sccmC2H4 10 sccmH2 800 sccm

Generation IIFull Wafer Production

Generation IIFull Wafer Production

50 μm

2 0

1 5

1 0

5N

umbe

r

2 01 0D iam e te r (nm)500 nm

134 plusmn 030 nm

1 All nanotubes grow normal to the c axis on a-plane sapphire2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin11 All nanotubes grow normal to the c axis on aAll nanotubes grow normal to the c axis on a--plane sapphireplane sapphire2 Narrow diameter distribution of 2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin

c axis

Aligned Nanotubes Grown on a-Plane SapphireAligned Nanotubes Grown on a-Plane Sapphire

Zhou et al JACS 127 5294 (2005)

Zhou Zhou et alet al Nano Letters Nano Letters (2006)(2006)(Top ten hot articles in 2006)

High density SWNTsUp to 40 nanotubes μmInter-nanotube spacing ~ 25 nm

Low density SWNTs

Control of Nanotube DensityControl of Nanotube Density

Zhou et al JACS 127 5294 (2005) Zhou Zhou et alet al Nano Letters (2006) Nano Letters (2006)

a-plane

Red spheres oxygen atomsBlue spheres aluminum atomsPurple plane a-plane orientation

Hypothetic Schematic Diagram of SWNT on a-Plane SapphireHypothetic Schematic Diagram of SWNT on a-Plane Sapphire

Calculation of Lennard-Jones Potential Calculation of Lennard-Jones Potential

sumsum⎥⎥⎥

⎦

⎤

⎢⎢⎢

⎣

⎡

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

minusminus⎟

⎟

⎠

⎞

⎜⎜

⎝

⎛

minus+

⎥⎥

⎦

⎤

⎢⎢

⎣

⎡

⎟⎟⎠

⎞⎜⎜⎝

⎛

minusminus⎟

⎟⎠

⎞⎜⎜⎝

⎛

minus=

j j

CAl

j

CAlCAl

i i

CO

i

COCO rrrrrrrr

rU

612612

44)( vvvvvvvvv σσ

εσσ

ε

a carbon atom and oxygen atoms in sapphire

a carbon atom and oxygen atoms in sapphire

a carbon atom and Al atoms in sapphire

a carbon atom and Al atoms in sapphire

Interaction between

Interaction between

C-plane C-plane a-plane a-plane

Potential wellPotential wellZhou Zhou et alet al JPCC JPCC 112 15929 (200(20088))

Synthesis of Nanotubes with Controlled Orientations and Positions

Synthesis of Nanotubes with Controlled Orientations and Positions

Catalyst

Photo Resist

QuartzSapphire

Catalyst Island

Aligned NanotubesMetal Electrode

SD

G

Dielectric Layer

3-10 nanotubes microm

Aligned Nanotubes on Quartz Using Patterned CatalystAligned Nanotubes on Quartz Using Patterned Catalystcatalyst

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

(a)

Poly Si Gate

Gate Oxide

SourceDrain Electrode

(b)

NanotubeGate Dielectric

Gate

SourceDrain Electrode

Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)

Comparison between SiliconComparison between Silicon--onon--insulator (SOI) and insulator (SOI) and NanotubeNanotube--onon--Insulator (NOI)Insulator (NOI)

SOISOISOI NOINOINOI

Common Features1 Active material (Si or SWNT) is all over the surface2 Many devices can be patterned anywhere on the substrate3 Unwanted silicon or SWNTs can be removed via etching4 SOI and NOI offer minimized parasitic capacitance faster switching speed

and lower dynamic power consumption

Common FeaturesCommon Features11 Active material (Si or SWNT) is all over the surfaceActive material (Si or SWNT) is all over the surface22 Many devices can be patterned anywhere on the substrateMany devices can be patterned anywhere on the substrate33 Unwanted silicon or Unwanted silicon or SWNTsSWNTs can be removed via etchingcan be removed via etching44 SOI and NOI offer minimized parasitic capacitance faster switchSOI and NOI offer minimized parasitic capacitance faster switching speed ing speed

and lower dynamic power consumptionand lower dynamic power consumption Zhou et al Nano Letters (2006)

a-Sapphire

Wafer-Scale Aligned Nanotube SynthesisWafer-Scale Aligned Nanotube Synthesis

1200

1000

800

600

400

200

Tem

pera

ture

200150100500

Time (min)

Growth Annealing

Key meticulous temperature control amp uniform growth

1μm

Quartz 1000

800

600

400

200Tem

pera

ture

6004002000

Time (min)

Growth Annealing

1μm

4 inch substrate

Gas in

Gas out

Quartz or Sapphire with patterned

catalyst

9 feet-long growth furnace with three-zone

Wafer-Scale CNT TransferWafer-Scale CNT TransferTransfer fullTransfer full--wafer of wafer of CNTsCNTs from quartz growth substrate to SiOfrom quartz growth substrate to SiO22Si fabrication Si fabrication

substrate substrate allows largeallows large--scale integrationscale integration

Nano Lett 9 189ndash197 20094

Wafer-Scale Aligned Nanotube Device FabricationWafer-Scale Aligned Nanotube Device Fabrication

Back-Gated Submicron TransistorsBack-Gated Submicron Transistors

Back-gated transistors

1 microm

L = 1 microm

1 microm

L = 075 microm

1 microm

L = 05 microm

I-Vg curves Channel length dependence

-120

-100

-80

-60

-40

-20

0

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

-60

-40

-20

0

I ds (μ

Α)

-1500Vds (V)

-1 V

-08 V

-06 V

-04 V

-02 V

Vg from -8V to 8V

15

10

05

I ds (m

A)

-10 -5 0 5 10Vg (V)

L = 05 microm L = 075 microm L = 1 microm L = 2 microm L = 5 microm L = 10 microm L = 20 microm

80

60

40

20

gm

(μ S

)

5 6 7 81

2 3 4 5 6 7 810

2

L(μm)

2

4

6810-6

2

4

6810-5

I DW

(mA

microm

) gm

Ion Ioff

Top-gated transistors

075 μmG

S

D

Al2O3

15

10

5

0

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

10-8

10-7

10-6

10-5

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

15

10

5

0

-5

-10

-15

I ds (μ

Α)

-10 -05 00 05 10Vds (V)

I-Vg curves I-Vds curves

Top-Gated Submicron TransistorsTop-Gated Submicron Transistors

N-type nanotube transistorsN-type nanotube transistorsHydrazine(NHydrazine(N22HH44) doping) doping

12

10

08

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds =01 V Vds =03 V Vds =05 V Vds =07 V Vds =09 V Vds =11 V

Before

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds=01 VVds=03 VVds=05VVds=07 VVds=09 VVds=11 V

After

Gain asymp54

10

08

06

04

02

00

Vou

t (V)

50454035302520

Vin (V)

6

5

4

3

2

1

0

I (nA)

Vout

I

Inverter

Gain =54

K doping

10

8

6

4

2

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

Before K doping After K doping

Gain asymp 5

p-type

n-type

15

10

05

00V

out (

V)

252015100500

Vin (V)

Gain=5

Potassium Doping and CMOS InverterPotassium Doping and CMOS Inverter

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

CMOS NAND amp NORCMOS NAND amp NORIndividual back-gated

NOR NAND

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

10 μm 10 μm10 μm

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Original MotivationMoorersquos Law

Original MotivationMoorersquos Law

1950 1970 1990 2010 2030

1 m

1 cm

Year

VLSI

Integratedcircuits

Transistor

Vacuum valves

Molecular dimensions

1 μm

10 nm

1 Α

Device size

From Intel

Si Substrate

Metal Gate

High-kTri-Gate

S

G

D

III-V

S

Carbon Nanotube FET

50 nm35 nm

30 nm

SiGe SD

Strained Silicon

Future options subject to research amp change

SiGe SD

Strained Silicon

90 nm65 nm

45 nm32 nm

20032005

20072009

2011+

Technology Generation

Source Intel

20 nm 10 nm

5 nm5 nm

5 nm

Nanowire

Manufacturing Development Research

Transistor Research

Research OptionsHigh-K amp Metal GateNon-planar TrigateIII-V CNT NW

CNT is a tubular form of carbon with diameter as small as 1 nm Length few nm to cm

CNT is configurationally equivalent to a two dimensional graphenesheet rolled into a tube

CNT exhibits1 Carrier mobility ~ 100000 cm2Vs2 Youngrsquos modulus over 1 Tera

Pascal as stiff as diamond3 Tensile strength ~ 200 GPa

Zigzag

Armchair

Chiral

MOLECULAR STRUCTUREMOLECULAR STRUCTURE

CNT can be metallic or semiconducting depending on chirality

Benchmarking CNT FETsBenchmarking CNT FETs

1

10

100

1000

10000

100000

130 90 65 45 22

Technology Node (nm)

Nor

mal

ized

FO

A

26X25X

28X 27X

Intrinsic CNT

MOS CNT FET

Band-edge SB CNTMidgap SB CNT

5000X

60X

50X20X

Si MOSFET

Source Ali Keshavarzi Intel

Nanotube Transistor ResearchNanotube Transistor ResearchGate

8nm HfO2

SiO2

p++ Si

PdPd CNT

Javey et al Nano Letters 4 1319 2004Delft Tans et al Nature 393 49 1998

Many people have studied individual nanotube transistors however the challenge is to integrate nanotube devices

Many people have studied individual nanotube transistors however the challenge is to integrate nanotube devices

Appenzeller et al PRL 93 19 2005

Drain

SourceGate

DrainSourceGate

Sapphire Substrate

GateOxide

Liu et al Nano Letters 6 34 2006

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes

Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes

SiSiO2

PMMA

Catalyst

CH4nanotube

Catalyst island

900 ordmC900 ordmC

metal electrode

H Dai et al Nature 395 878 (1998)

Infrastructure Nanotube CVD Generation IInfrastructure Nanotube CVD Generation I

1 μm

1 μm

26 nm in diameter

10 nm in diameter

High-quality nanotubes can be grown at specific positions

-60

-50

-40

-30

-20

-10

0

I DS(

nA)

-10-08-06-04-0200VDS(V)

Vg -4 V

0 V

2 V

6 V

Nanotube transistor can be easily produced

Si back gate

SiO2

S D

Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter

Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter

Carbon Nanotube Field-Effect Inverters X Liu R Lee J Han C Zhou Appl Phys Lett 79 3329 (2001)

One of the first integrated systems made of carbon nanotubes

Si back gate

K

Vin

Vout

VDD GND

p-type CNT n-type CNT

60

40

20

0

I DS(

nA)

-4 -2 0 2 4Vg(V)

VDS=10 mV

P type MOSFET12

8

4

0

I DS (

nA)

-4 -2 0 2 4Vg (V)

VDS=10 mV

N type MOSFET25

20

15

10

05

00

Vou

t(V)

252015100500Vin(V)

VDD=29 V

Vin Vout

0 V

VDD

p

n

Integrated Nanotube SystemsRing Oscillators Demonstrated by Avouris et al

Integrated Nanotube SystemsRing Oscillators Demonstrated by Avouris et al

Ph Avouris et al Science 311 1735 (2006)

Is there a way to assemble large quantities of nanotube devices

State-of-the-art of nanotube integration

Aligned Nanotubes for Devices and Circuits Aligned Nanotubes for Devices and Circuits

-- Project Mission Project Mission We want to tackle the challenging issue of We want to tackle the challenging issue of nanotube nanotube assembly and integrationassembly and integration

We want to grow carbon nanotubes withWe want to grow carbon nanotubes withControlled orientation (achieved by using Controlled orientation (achieved by using sapphire and quartz) sapphire and quartz) Controlled position (achieved) Controlled position (achieved) Controlled density (achieved) Controlled density (achieved) Controlled diameter (ongoing)Controlled diameter (ongoing)Controlled Controlled chiralitychirality (ongoing)(ongoing)

-- Our Approach Our Approach A novel nanotubeA novel nanotube--onon--insulator (NOI) insulator (NOI) approach based on approach based on aligned nanotubesaligned nanotubes for for integrated nanotube circuitsintegrated nanotube circuits Nanotube

devicesNanotube

circuits

Quartz SubstrateCatalyst Particle

Quartz Substrate

Nanotube

One of the first to grow aligned nanotubes on sapphireOne of the first to grow aligned nanotubes on sapphireJ of Am Chem Soc 127 5294 J of Am Chem Soc 127 5294 -- 5295 (2005) 5295 (2005)

The first to make aligned nanotube transistorsThe first to make aligned nanotube transistorsNano Letters 6 34Nano Letters 6 34--39 (2006)39 (2006)Reported by Reported by Scientific AmericanScientific American (April 2006 P16) (April 2006 P16)

The first to demonstrate waferThe first to demonstrate wafer--scale processing of aligned scale processing of aligned nanotube devices and circuitsnanotube devices and circuits

Logic circuits (CMOS inverter NAND NOR)Logic circuits (CMOS inverter NAND NOR)

The first to make transparent nanotube devicesThe first to make transparent nanotube devicesACS Nano in press (2008)ACS Nano in press (2008)

Chip

1

2

3

4

5

Our Achievements on Aligned Single-Walled NanotubesOur Achievements on Aligned SingleOur Achievements on Aligned Single--Walled NanotubesWalled Nanotubes

Synthesis of Aligned Nanotubes on Sapphire QuartzSynthesis of Aligned Nanotubes on Sapphire Quartz

Gas in

Gas out

Sapphire with catalyst

Substrate Sapphire quartzCatalyst FerritinTemperature 900degCGas flow rate

CH4 2000 sccmC2H4 10 sccmH2 800 sccm

Generation IIFull Wafer Production

Generation IIFull Wafer Production

50 μm

2 0

1 5

1 0

5N

umbe

r

2 01 0D iam e te r (nm)500 nm

134 plusmn 030 nm

1 All nanotubes grow normal to the c axis on a-plane sapphire2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin11 All nanotubes grow normal to the c axis on aAll nanotubes grow normal to the c axis on a--plane sapphireplane sapphire2 Narrow diameter distribution of 2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin

c axis

Aligned Nanotubes Grown on a-Plane SapphireAligned Nanotubes Grown on a-Plane Sapphire

Zhou et al JACS 127 5294 (2005)

Zhou Zhou et alet al Nano Letters Nano Letters (2006)(2006)(Top ten hot articles in 2006)

High density SWNTsUp to 40 nanotubes μmInter-nanotube spacing ~ 25 nm

Low density SWNTs

Control of Nanotube DensityControl of Nanotube Density

Zhou et al JACS 127 5294 (2005) Zhou Zhou et alet al Nano Letters (2006) Nano Letters (2006)

a-plane

Red spheres oxygen atomsBlue spheres aluminum atomsPurple plane a-plane orientation

Hypothetic Schematic Diagram of SWNT on a-Plane SapphireHypothetic Schematic Diagram of SWNT on a-Plane Sapphire

Calculation of Lennard-Jones Potential Calculation of Lennard-Jones Potential

sumsum⎥⎥⎥

⎦

⎤

⎢⎢⎢

⎣

⎡

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

minusminus⎟

⎟

⎠

⎞

⎜⎜

⎝

⎛

minus+

⎥⎥

⎦

⎤

⎢⎢

⎣

⎡

⎟⎟⎠

⎞⎜⎜⎝

⎛

minusminus⎟

⎟⎠

⎞⎜⎜⎝

⎛

minus=

j j

CAl

j

CAlCAl

i i

CO

i

COCO rrrrrrrr

rU

612612

44)( vvvvvvvvv σσ

εσσ

ε

a carbon atom and oxygen atoms in sapphire

a carbon atom and oxygen atoms in sapphire

a carbon atom and Al atoms in sapphire

a carbon atom and Al atoms in sapphire

Interaction between

Interaction between

C-plane C-plane a-plane a-plane

Potential wellPotential wellZhou Zhou et alet al JPCC JPCC 112 15929 (200(20088))

Synthesis of Nanotubes with Controlled Orientations and Positions

Synthesis of Nanotubes with Controlled Orientations and Positions

Catalyst

Photo Resist

QuartzSapphire

Catalyst Island

Aligned NanotubesMetal Electrode

SD

G

Dielectric Layer

3-10 nanotubes microm

Aligned Nanotubes on Quartz Using Patterned CatalystAligned Nanotubes on Quartz Using Patterned Catalystcatalyst

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

(a)

Poly Si Gate

Gate Oxide

SourceDrain Electrode

(b)

NanotubeGate Dielectric

Gate

SourceDrain Electrode

Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)

Comparison between SiliconComparison between Silicon--onon--insulator (SOI) and insulator (SOI) and NanotubeNanotube--onon--Insulator (NOI)Insulator (NOI)

SOISOISOI NOINOINOI

Common Features1 Active material (Si or SWNT) is all over the surface2 Many devices can be patterned anywhere on the substrate3 Unwanted silicon or SWNTs can be removed via etching4 SOI and NOI offer minimized parasitic capacitance faster switching speed

and lower dynamic power consumption

Common FeaturesCommon Features11 Active material (Si or SWNT) is all over the surfaceActive material (Si or SWNT) is all over the surface22 Many devices can be patterned anywhere on the substrateMany devices can be patterned anywhere on the substrate33 Unwanted silicon or Unwanted silicon or SWNTsSWNTs can be removed via etchingcan be removed via etching44 SOI and NOI offer minimized parasitic capacitance faster switchSOI and NOI offer minimized parasitic capacitance faster switching speed ing speed

and lower dynamic power consumptionand lower dynamic power consumption Zhou et al Nano Letters (2006)

a-Sapphire

Wafer-Scale Aligned Nanotube SynthesisWafer-Scale Aligned Nanotube Synthesis

1200

1000

800

600

400

200

Tem

pera

ture

200150100500

Time (min)

Growth Annealing

Key meticulous temperature control amp uniform growth

1μm

Quartz 1000

800

600

400

200Tem

pera

ture

6004002000

Time (min)

Growth Annealing

1μm

4 inch substrate

Gas in

Gas out

Quartz or Sapphire with patterned

catalyst

9 feet-long growth furnace with three-zone

Wafer-Scale CNT TransferWafer-Scale CNT TransferTransfer fullTransfer full--wafer of wafer of CNTsCNTs from quartz growth substrate to SiOfrom quartz growth substrate to SiO22Si fabrication Si fabrication

substrate substrate allows largeallows large--scale integrationscale integration

Nano Lett 9 189ndash197 20094

Wafer-Scale Aligned Nanotube Device FabricationWafer-Scale Aligned Nanotube Device Fabrication

Back-Gated Submicron TransistorsBack-Gated Submicron Transistors

Back-gated transistors

1 microm

L = 1 microm

1 microm

L = 075 microm

1 microm

L = 05 microm

I-Vg curves Channel length dependence

-120

-100

-80

-60

-40

-20

0

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

-60

-40

-20

0

I ds (μ

Α)

-1500Vds (V)

-1 V

-08 V

-06 V

-04 V

-02 V

Vg from -8V to 8V

15

10

05

I ds (m

A)

-10 -5 0 5 10Vg (V)

L = 05 microm L = 075 microm L = 1 microm L = 2 microm L = 5 microm L = 10 microm L = 20 microm

80

60

40

20

gm

(μ S

)

5 6 7 81

2 3 4 5 6 7 810

2

L(μm)

2

4

6810-6

2

4

6810-5

I DW

(mA

microm

) gm

Ion Ioff

Top-gated transistors

075 μmG

S

D

Al2O3

15

10

5

0

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

10-8

10-7

10-6

10-5

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

15

10

5

0

-5

-10

-15

I ds (μ

Α)

-10 -05 00 05 10Vds (V)

I-Vg curves I-Vds curves

Top-Gated Submicron TransistorsTop-Gated Submicron Transistors

N-type nanotube transistorsN-type nanotube transistorsHydrazine(NHydrazine(N22HH44) doping) doping

12

10

08

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds =01 V Vds =03 V Vds =05 V Vds =07 V Vds =09 V Vds =11 V

Before

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds=01 VVds=03 VVds=05VVds=07 VVds=09 VVds=11 V

After

Gain asymp54

10

08

06

04

02

00

Vou

t (V)

50454035302520

Vin (V)

6

5

4

3

2

1

0

I (nA)

Vout

I

Inverter

Gain =54

K doping

10

8

6

4

2

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

Before K doping After K doping

Gain asymp 5

p-type

n-type

15

10

05

00V

out (

V)

252015100500

Vin (V)

Gain=5

Potassium Doping and CMOS InverterPotassium Doping and CMOS Inverter

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

CMOS NAND amp NORCMOS NAND amp NORIndividual back-gated

NOR NAND

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

10 μm 10 μm10 μm

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Original MotivationMoorersquos Law

Original MotivationMoorersquos Law

1950 1970 1990 2010 2030

1 m

1 cm

Year

VLSI

Integratedcircuits

Transistor

Vacuum valves

Molecular dimensions

1 μm

10 nm

1 Α

Device size

From Intel

Si Substrate

Metal Gate

High-kTri-Gate

S

G

D

III-V

S

Carbon Nanotube FET

50 nm35 nm

30 nm

SiGe SD

Strained Silicon

Future options subject to research amp change

SiGe SD

Strained Silicon

90 nm65 nm

45 nm32 nm

20032005

20072009

2011+

Technology Generation

Source Intel

20 nm 10 nm

5 nm5 nm

5 nm

Nanowire

Manufacturing Development Research

Transistor Research

Research OptionsHigh-K amp Metal GateNon-planar TrigateIII-V CNT NW

CNT is a tubular form of carbon with diameter as small as 1 nm Length few nm to cm

CNT is configurationally equivalent to a two dimensional graphenesheet rolled into a tube

CNT exhibits1 Carrier mobility ~ 100000 cm2Vs2 Youngrsquos modulus over 1 Tera

Pascal as stiff as diamond3 Tensile strength ~ 200 GPa

Zigzag

Armchair

Chiral

MOLECULAR STRUCTUREMOLECULAR STRUCTURE

CNT can be metallic or semiconducting depending on chirality

Benchmarking CNT FETsBenchmarking CNT FETs

1

10

100

1000

10000

100000

130 90 65 45 22

Technology Node (nm)

Nor

mal

ized

FO

A

26X25X

28X 27X

Intrinsic CNT

MOS CNT FET

Band-edge SB CNTMidgap SB CNT

5000X

60X

50X20X

Si MOSFET

Source Ali Keshavarzi Intel

Nanotube Transistor ResearchNanotube Transistor ResearchGate

8nm HfO2

SiO2

p++ Si

PdPd CNT

Javey et al Nano Letters 4 1319 2004Delft Tans et al Nature 393 49 1998

Many people have studied individual nanotube transistors however the challenge is to integrate nanotube devices

Many people have studied individual nanotube transistors however the challenge is to integrate nanotube devices

Appenzeller et al PRL 93 19 2005

Drain

SourceGate

DrainSourceGate

Sapphire Substrate

GateOxide

Liu et al Nano Letters 6 34 2006

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes

Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes

SiSiO2

PMMA

Catalyst

CH4nanotube

Catalyst island

900 ordmC900 ordmC

metal electrode

H Dai et al Nature 395 878 (1998)

Infrastructure Nanotube CVD Generation IInfrastructure Nanotube CVD Generation I

1 μm

1 μm

26 nm in diameter

10 nm in diameter

High-quality nanotubes can be grown at specific positions

-60

-50

-40

-30

-20

-10

0

I DS(

nA)

-10-08-06-04-0200VDS(V)

Vg -4 V

0 V

2 V

6 V

Nanotube transistor can be easily produced

Si back gate

SiO2

S D

Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter

Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter

Carbon Nanotube Field-Effect Inverters X Liu R Lee J Han C Zhou Appl Phys Lett 79 3329 (2001)

One of the first integrated systems made of carbon nanotubes

Si back gate

K

Vin

Vout

VDD GND

p-type CNT n-type CNT

60

40

20

0

I DS(

nA)

-4 -2 0 2 4Vg(V)

VDS=10 mV

P type MOSFET12

8

4

0

I DS (

nA)

-4 -2 0 2 4Vg (V)

VDS=10 mV

N type MOSFET25

20

15

10

05

00

Vou

t(V)

252015100500Vin(V)

VDD=29 V

Vin Vout

0 V

VDD

p

n

Integrated Nanotube SystemsRing Oscillators Demonstrated by Avouris et al

Integrated Nanotube SystemsRing Oscillators Demonstrated by Avouris et al

Ph Avouris et al Science 311 1735 (2006)

Is there a way to assemble large quantities of nanotube devices

State-of-the-art of nanotube integration

Aligned Nanotubes for Devices and Circuits Aligned Nanotubes for Devices and Circuits

-- Project Mission Project Mission We want to tackle the challenging issue of We want to tackle the challenging issue of nanotube nanotube assembly and integrationassembly and integration

We want to grow carbon nanotubes withWe want to grow carbon nanotubes withControlled orientation (achieved by using Controlled orientation (achieved by using sapphire and quartz) sapphire and quartz) Controlled position (achieved) Controlled position (achieved) Controlled density (achieved) Controlled density (achieved) Controlled diameter (ongoing)Controlled diameter (ongoing)Controlled Controlled chiralitychirality (ongoing)(ongoing)

-- Our Approach Our Approach A novel nanotubeA novel nanotube--onon--insulator (NOI) insulator (NOI) approach based on approach based on aligned nanotubesaligned nanotubes for for integrated nanotube circuitsintegrated nanotube circuits Nanotube

devicesNanotube

circuits

Quartz SubstrateCatalyst Particle

Quartz Substrate

Nanotube

One of the first to grow aligned nanotubes on sapphireOne of the first to grow aligned nanotubes on sapphireJ of Am Chem Soc 127 5294 J of Am Chem Soc 127 5294 -- 5295 (2005) 5295 (2005)

The first to make aligned nanotube transistorsThe first to make aligned nanotube transistorsNano Letters 6 34Nano Letters 6 34--39 (2006)39 (2006)Reported by Reported by Scientific AmericanScientific American (April 2006 P16) (April 2006 P16)

The first to demonstrate waferThe first to demonstrate wafer--scale processing of aligned scale processing of aligned nanotube devices and circuitsnanotube devices and circuits

Logic circuits (CMOS inverter NAND NOR)Logic circuits (CMOS inverter NAND NOR)

The first to make transparent nanotube devicesThe first to make transparent nanotube devicesACS Nano in press (2008)ACS Nano in press (2008)

Chip

1

2

3

4

5

Our Achievements on Aligned Single-Walled NanotubesOur Achievements on Aligned SingleOur Achievements on Aligned Single--Walled NanotubesWalled Nanotubes

Synthesis of Aligned Nanotubes on Sapphire QuartzSynthesis of Aligned Nanotubes on Sapphire Quartz

Gas in

Gas out

Sapphire with catalyst

Substrate Sapphire quartzCatalyst FerritinTemperature 900degCGas flow rate

CH4 2000 sccmC2H4 10 sccmH2 800 sccm

Generation IIFull Wafer Production

Generation IIFull Wafer Production

50 μm

2 0

1 5

1 0

5N

umbe

r

2 01 0D iam e te r (nm)500 nm

134 plusmn 030 nm

1 All nanotubes grow normal to the c axis on a-plane sapphire2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin11 All nanotubes grow normal to the c axis on aAll nanotubes grow normal to the c axis on a--plane sapphireplane sapphire2 Narrow diameter distribution of 2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin

c axis

Aligned Nanotubes Grown on a-Plane SapphireAligned Nanotubes Grown on a-Plane Sapphire

Zhou et al JACS 127 5294 (2005)

Zhou Zhou et alet al Nano Letters Nano Letters (2006)(2006)(Top ten hot articles in 2006)

High density SWNTsUp to 40 nanotubes μmInter-nanotube spacing ~ 25 nm

Low density SWNTs

Control of Nanotube DensityControl of Nanotube Density

Zhou et al JACS 127 5294 (2005) Zhou Zhou et alet al Nano Letters (2006) Nano Letters (2006)

a-plane

Red spheres oxygen atomsBlue spheres aluminum atomsPurple plane a-plane orientation

Hypothetic Schematic Diagram of SWNT on a-Plane SapphireHypothetic Schematic Diagram of SWNT on a-Plane Sapphire

Calculation of Lennard-Jones Potential Calculation of Lennard-Jones Potential

sumsum⎥⎥⎥

⎦

⎤

⎢⎢⎢

⎣

⎡

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

minusminus⎟

⎟

⎠

⎞

⎜⎜

⎝

⎛

minus+

⎥⎥

⎦

⎤

⎢⎢

⎣

⎡

⎟⎟⎠

⎞⎜⎜⎝

⎛

minusminus⎟

⎟⎠

⎞⎜⎜⎝

⎛

minus=

j j

CAl

j

CAlCAl

i i

CO

i

COCO rrrrrrrr

rU

612612

44)( vvvvvvvvv σσ

εσσ

ε

a carbon atom and oxygen atoms in sapphire

a carbon atom and oxygen atoms in sapphire

a carbon atom and Al atoms in sapphire

a carbon atom and Al atoms in sapphire

Interaction between

Interaction between

C-plane C-plane a-plane a-plane

Potential wellPotential wellZhou Zhou et alet al JPCC JPCC 112 15929 (200(20088))

Synthesis of Nanotubes with Controlled Orientations and Positions

Synthesis of Nanotubes with Controlled Orientations and Positions

Catalyst

Photo Resist

QuartzSapphire

Catalyst Island

Aligned NanotubesMetal Electrode

SD

G

Dielectric Layer

3-10 nanotubes microm

Aligned Nanotubes on Quartz Using Patterned CatalystAligned Nanotubes on Quartz Using Patterned Catalystcatalyst

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

(a)

Poly Si Gate

Gate Oxide

SourceDrain Electrode

(b)

NanotubeGate Dielectric

Gate

SourceDrain Electrode

Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)

Comparison between SiliconComparison between Silicon--onon--insulator (SOI) and insulator (SOI) and NanotubeNanotube--onon--Insulator (NOI)Insulator (NOI)

SOISOISOI NOINOINOI

Common Features1 Active material (Si or SWNT) is all over the surface2 Many devices can be patterned anywhere on the substrate3 Unwanted silicon or SWNTs can be removed via etching4 SOI and NOI offer minimized parasitic capacitance faster switching speed

and lower dynamic power consumption

Common FeaturesCommon Features11 Active material (Si or SWNT) is all over the surfaceActive material (Si or SWNT) is all over the surface22 Many devices can be patterned anywhere on the substrateMany devices can be patterned anywhere on the substrate33 Unwanted silicon or Unwanted silicon or SWNTsSWNTs can be removed via etchingcan be removed via etching44 SOI and NOI offer minimized parasitic capacitance faster switchSOI and NOI offer minimized parasitic capacitance faster switching speed ing speed

and lower dynamic power consumptionand lower dynamic power consumption Zhou et al Nano Letters (2006)

a-Sapphire

Wafer-Scale Aligned Nanotube SynthesisWafer-Scale Aligned Nanotube Synthesis

1200

1000

800

600

400

200

Tem

pera

ture

200150100500

Time (min)

Growth Annealing

Key meticulous temperature control amp uniform growth

1μm

Quartz 1000

800

600

400

200Tem

pera

ture

6004002000

Time (min)

Growth Annealing

1μm

4 inch substrate

Gas in

Gas out

Quartz or Sapphire with patterned

catalyst

9 feet-long growth furnace with three-zone

Wafer-Scale CNT TransferWafer-Scale CNT TransferTransfer fullTransfer full--wafer of wafer of CNTsCNTs from quartz growth substrate to SiOfrom quartz growth substrate to SiO22Si fabrication Si fabrication

substrate substrate allows largeallows large--scale integrationscale integration

Nano Lett 9 189ndash197 20094

Wafer-Scale Aligned Nanotube Device FabricationWafer-Scale Aligned Nanotube Device Fabrication

Back-Gated Submicron TransistorsBack-Gated Submicron Transistors

Back-gated transistors

1 microm

L = 1 microm

1 microm

L = 075 microm

1 microm

L = 05 microm

I-Vg curves Channel length dependence

-120

-100

-80

-60

-40

-20

0

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

-60

-40

-20

0

I ds (μ

Α)

-1500Vds (V)

-1 V

-08 V

-06 V

-04 V

-02 V

Vg from -8V to 8V

15

10

05

I ds (m

A)

-10 -5 0 5 10Vg (V)

L = 05 microm L = 075 microm L = 1 microm L = 2 microm L = 5 microm L = 10 microm L = 20 microm

80

60

40

20

gm

(μ S

)

5 6 7 81

2 3 4 5 6 7 810

2

L(μm)

2

4

6810-6

2

4

6810-5

I DW

(mA

microm

) gm

Ion Ioff

Top-gated transistors

075 μmG

S

D

Al2O3

15

10

5

0

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

10-8

10-7

10-6

10-5

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

15

10

5

0

-5

-10

-15

I ds (μ

Α)

-10 -05 00 05 10Vds (V)

I-Vg curves I-Vds curves

Top-Gated Submicron TransistorsTop-Gated Submicron Transistors

N-type nanotube transistorsN-type nanotube transistorsHydrazine(NHydrazine(N22HH44) doping) doping

12

10

08

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds =01 V Vds =03 V Vds =05 V Vds =07 V Vds =09 V Vds =11 V

Before

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds=01 VVds=03 VVds=05VVds=07 VVds=09 VVds=11 V

After

Gain asymp54

10

08

06

04

02

00

Vou

t (V)

50454035302520

Vin (V)

6

5

4

3

2

1

0

I (nA)

Vout

I

Inverter

Gain =54

K doping

10

8

6

4

2

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

Before K doping After K doping

Gain asymp 5

p-type

n-type

15

10

05

00V

out (

V)

252015100500

Vin (V)

Gain=5

Potassium Doping and CMOS InverterPotassium Doping and CMOS Inverter

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

CMOS NAND amp NORCMOS NAND amp NORIndividual back-gated

NOR NAND

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

10 μm 10 μm10 μm

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Si Substrate

Metal Gate

High-kTri-Gate

S

G

D

III-V

S

Carbon Nanotube FET

50 nm35 nm

30 nm

SiGe SD

Strained Silicon

Future options subject to research amp change

SiGe SD

Strained Silicon

90 nm65 nm

45 nm32 nm

20032005

20072009

2011+

Technology Generation

Source Intel

20 nm 10 nm

5 nm5 nm

5 nm

Nanowire

Manufacturing Development Research

Transistor Research

Research OptionsHigh-K amp Metal GateNon-planar TrigateIII-V CNT NW

CNT is a tubular form of carbon with diameter as small as 1 nm Length few nm to cm

CNT is configurationally equivalent to a two dimensional graphenesheet rolled into a tube

CNT exhibits1 Carrier mobility ~ 100000 cm2Vs2 Youngrsquos modulus over 1 Tera

Pascal as stiff as diamond3 Tensile strength ~ 200 GPa

Zigzag

Armchair

Chiral

MOLECULAR STRUCTUREMOLECULAR STRUCTURE

CNT can be metallic or semiconducting depending on chirality

Benchmarking CNT FETsBenchmarking CNT FETs

1

10

100

1000

10000

100000

130 90 65 45 22

Technology Node (nm)

Nor

mal

ized

FO

A

26X25X

28X 27X

Intrinsic CNT

MOS CNT FET

Band-edge SB CNTMidgap SB CNT

5000X

60X

50X20X

Si MOSFET

Source Ali Keshavarzi Intel

Nanotube Transistor ResearchNanotube Transistor ResearchGate

8nm HfO2

SiO2

p++ Si

PdPd CNT

Javey et al Nano Letters 4 1319 2004Delft Tans et al Nature 393 49 1998

Many people have studied individual nanotube transistors however the challenge is to integrate nanotube devices

Many people have studied individual nanotube transistors however the challenge is to integrate nanotube devices

Appenzeller et al PRL 93 19 2005

Drain

SourceGate

DrainSourceGate

Sapphire Substrate

GateOxide

Liu et al Nano Letters 6 34 2006

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes

Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes

SiSiO2

PMMA

Catalyst

CH4nanotube

Catalyst island

900 ordmC900 ordmC

metal electrode

H Dai et al Nature 395 878 (1998)

Infrastructure Nanotube CVD Generation IInfrastructure Nanotube CVD Generation I

1 μm

1 μm

26 nm in diameter

10 nm in diameter

High-quality nanotubes can be grown at specific positions

-60

-50

-40

-30

-20

-10

0

I DS(

nA)

-10-08-06-04-0200VDS(V)

Vg -4 V

0 V

2 V

6 V

Nanotube transistor can be easily produced

Si back gate

SiO2

S D

Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter

Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter

Carbon Nanotube Field-Effect Inverters X Liu R Lee J Han C Zhou Appl Phys Lett 79 3329 (2001)

One of the first integrated systems made of carbon nanotubes

Si back gate

K

Vin

Vout

VDD GND

p-type CNT n-type CNT

60

40

20

0

I DS(

nA)

-4 -2 0 2 4Vg(V)

VDS=10 mV

P type MOSFET12

8

4

0

I DS (

nA)

-4 -2 0 2 4Vg (V)

VDS=10 mV

N type MOSFET25

20

15

10

05

00

Vou

t(V)

252015100500Vin(V)

VDD=29 V

Vin Vout

0 V

VDD

p

n

Integrated Nanotube SystemsRing Oscillators Demonstrated by Avouris et al

Integrated Nanotube SystemsRing Oscillators Demonstrated by Avouris et al

Ph Avouris et al Science 311 1735 (2006)

Is there a way to assemble large quantities of nanotube devices

State-of-the-art of nanotube integration

Aligned Nanotubes for Devices and Circuits Aligned Nanotubes for Devices and Circuits

-- Project Mission Project Mission We want to tackle the challenging issue of We want to tackle the challenging issue of nanotube nanotube assembly and integrationassembly and integration

We want to grow carbon nanotubes withWe want to grow carbon nanotubes withControlled orientation (achieved by using Controlled orientation (achieved by using sapphire and quartz) sapphire and quartz) Controlled position (achieved) Controlled position (achieved) Controlled density (achieved) Controlled density (achieved) Controlled diameter (ongoing)Controlled diameter (ongoing)Controlled Controlled chiralitychirality (ongoing)(ongoing)

-- Our Approach Our Approach A novel nanotubeA novel nanotube--onon--insulator (NOI) insulator (NOI) approach based on approach based on aligned nanotubesaligned nanotubes for for integrated nanotube circuitsintegrated nanotube circuits Nanotube

devicesNanotube

circuits

Quartz SubstrateCatalyst Particle

Quartz Substrate

Nanotube

One of the first to grow aligned nanotubes on sapphireOne of the first to grow aligned nanotubes on sapphireJ of Am Chem Soc 127 5294 J of Am Chem Soc 127 5294 -- 5295 (2005) 5295 (2005)

The first to make aligned nanotube transistorsThe first to make aligned nanotube transistorsNano Letters 6 34Nano Letters 6 34--39 (2006)39 (2006)Reported by Reported by Scientific AmericanScientific American (April 2006 P16) (April 2006 P16)

The first to demonstrate waferThe first to demonstrate wafer--scale processing of aligned scale processing of aligned nanotube devices and circuitsnanotube devices and circuits

Logic circuits (CMOS inverter NAND NOR)Logic circuits (CMOS inverter NAND NOR)

The first to make transparent nanotube devicesThe first to make transparent nanotube devicesACS Nano in press (2008)ACS Nano in press (2008)

Chip

1

2

3

4

5

Our Achievements on Aligned Single-Walled NanotubesOur Achievements on Aligned SingleOur Achievements on Aligned Single--Walled NanotubesWalled Nanotubes

Synthesis of Aligned Nanotubes on Sapphire QuartzSynthesis of Aligned Nanotubes on Sapphire Quartz

Gas in

Gas out

Sapphire with catalyst

Substrate Sapphire quartzCatalyst FerritinTemperature 900degCGas flow rate

CH4 2000 sccmC2H4 10 sccmH2 800 sccm

Generation IIFull Wafer Production

Generation IIFull Wafer Production

50 μm

2 0

1 5

1 0

5N

umbe

r

2 01 0D iam e te r (nm)500 nm

134 plusmn 030 nm

1 All nanotubes grow normal to the c axis on a-plane sapphire2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin11 All nanotubes grow normal to the c axis on aAll nanotubes grow normal to the c axis on a--plane sapphireplane sapphire2 Narrow diameter distribution of 2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin

c axis

Aligned Nanotubes Grown on a-Plane SapphireAligned Nanotubes Grown on a-Plane Sapphire

Zhou et al JACS 127 5294 (2005)

Zhou Zhou et alet al Nano Letters Nano Letters (2006)(2006)(Top ten hot articles in 2006)

High density SWNTsUp to 40 nanotubes μmInter-nanotube spacing ~ 25 nm

Low density SWNTs

Control of Nanotube DensityControl of Nanotube Density

Zhou et al JACS 127 5294 (2005) Zhou Zhou et alet al Nano Letters (2006) Nano Letters (2006)

a-plane

Red spheres oxygen atomsBlue spheres aluminum atomsPurple plane a-plane orientation

Hypothetic Schematic Diagram of SWNT on a-Plane SapphireHypothetic Schematic Diagram of SWNT on a-Plane Sapphire

Calculation of Lennard-Jones Potential Calculation of Lennard-Jones Potential

sumsum⎥⎥⎥

⎦

⎤

⎢⎢⎢

⎣

⎡

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

minusminus⎟

⎟

⎠

⎞

⎜⎜

⎝

⎛

minus+

⎥⎥

⎦

⎤

⎢⎢

⎣

⎡

⎟⎟⎠

⎞⎜⎜⎝

⎛

minusminus⎟

⎟⎠

⎞⎜⎜⎝

⎛

minus=

j j

CAl

j

CAlCAl

i i

CO

i

COCO rrrrrrrr

rU

612612

44)( vvvvvvvvv σσ

εσσ

ε

a carbon atom and oxygen atoms in sapphire

a carbon atom and oxygen atoms in sapphire

a carbon atom and Al atoms in sapphire

a carbon atom and Al atoms in sapphire

Interaction between

Interaction between

C-plane C-plane a-plane a-plane

Potential wellPotential wellZhou Zhou et alet al JPCC JPCC 112 15929 (200(20088))

Synthesis of Nanotubes with Controlled Orientations and Positions

Synthesis of Nanotubes with Controlled Orientations and Positions

Catalyst

Photo Resist

QuartzSapphire

Catalyst Island

Aligned NanotubesMetal Electrode

SD

G

Dielectric Layer

3-10 nanotubes microm

Aligned Nanotubes on Quartz Using Patterned CatalystAligned Nanotubes on Quartz Using Patterned Catalystcatalyst

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

(a)

Poly Si Gate

Gate Oxide

SourceDrain Electrode

(b)

NanotubeGate Dielectric

Gate

SourceDrain Electrode

Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)

Comparison between SiliconComparison between Silicon--onon--insulator (SOI) and insulator (SOI) and NanotubeNanotube--onon--Insulator (NOI)Insulator (NOI)

SOISOISOI NOINOINOI

Common Features1 Active material (Si or SWNT) is all over the surface2 Many devices can be patterned anywhere on the substrate3 Unwanted silicon or SWNTs can be removed via etching4 SOI and NOI offer minimized parasitic capacitance faster switching speed

and lower dynamic power consumption

Common FeaturesCommon Features11 Active material (Si or SWNT) is all over the surfaceActive material (Si or SWNT) is all over the surface22 Many devices can be patterned anywhere on the substrateMany devices can be patterned anywhere on the substrate33 Unwanted silicon or Unwanted silicon or SWNTsSWNTs can be removed via etchingcan be removed via etching44 SOI and NOI offer minimized parasitic capacitance faster switchSOI and NOI offer minimized parasitic capacitance faster switching speed ing speed

and lower dynamic power consumptionand lower dynamic power consumption Zhou et al Nano Letters (2006)

a-Sapphire

Wafer-Scale Aligned Nanotube SynthesisWafer-Scale Aligned Nanotube Synthesis

1200

1000

800

600

400

200

Tem

pera

ture

200150100500

Time (min)

Growth Annealing

Key meticulous temperature control amp uniform growth

1μm

Quartz 1000

800

600

400

200Tem

pera

ture

6004002000

Time (min)

Growth Annealing

1μm

4 inch substrate

Gas in

Gas out

Quartz or Sapphire with patterned

catalyst

9 feet-long growth furnace with three-zone

Wafer-Scale CNT TransferWafer-Scale CNT TransferTransfer fullTransfer full--wafer of wafer of CNTsCNTs from quartz growth substrate to SiOfrom quartz growth substrate to SiO22Si fabrication Si fabrication

substrate substrate allows largeallows large--scale integrationscale integration

Nano Lett 9 189ndash197 20094

Wafer-Scale Aligned Nanotube Device FabricationWafer-Scale Aligned Nanotube Device Fabrication

Back-Gated Submicron TransistorsBack-Gated Submicron Transistors

Back-gated transistors

1 microm

L = 1 microm

1 microm

L = 075 microm

1 microm

L = 05 microm

I-Vg curves Channel length dependence

-120

-100

-80

-60

-40

-20

0

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

-60

-40

-20

0

I ds (μ

Α)

-1500Vds (V)

-1 V

-08 V

-06 V

-04 V

-02 V

Vg from -8V to 8V

15

10

05

I ds (m

A)

-10 -5 0 5 10Vg (V)

L = 05 microm L = 075 microm L = 1 microm L = 2 microm L = 5 microm L = 10 microm L = 20 microm

80

60

40

20

gm

(μ S

)

5 6 7 81

2 3 4 5 6 7 810

2

L(μm)

2

4

6810-6

2

4

6810-5

I DW

(mA

microm

) gm

Ion Ioff

Top-gated transistors

075 μmG

S

D

Al2O3

15

10

5

0

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

10-8

10-7

10-6

10-5

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

15

10

5

0

-5

-10

-15

I ds (μ

Α)

-10 -05 00 05 10Vds (V)

I-Vg curves I-Vds curves

Top-Gated Submicron TransistorsTop-Gated Submicron Transistors

N-type nanotube transistorsN-type nanotube transistorsHydrazine(NHydrazine(N22HH44) doping) doping

12

10

08

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds =01 V Vds =03 V Vds =05 V Vds =07 V Vds =09 V Vds =11 V

Before

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds=01 VVds=03 VVds=05VVds=07 VVds=09 VVds=11 V

After

Gain asymp54

10

08

06

04

02

00

Vou

t (V)

50454035302520

Vin (V)

6

5

4

3

2

1

0

I (nA)

Vout

I

Inverter

Gain =54

K doping

10

8

6

4

2

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

Before K doping After K doping

Gain asymp 5

p-type

n-type

15

10

05

00V

out (

V)

252015100500

Vin (V)

Gain=5

Potassium Doping and CMOS InverterPotassium Doping and CMOS Inverter

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

CMOS NAND amp NORCMOS NAND amp NORIndividual back-gated

NOR NAND

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

10 μm 10 μm10 μm

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

CNT is a tubular form of carbon with diameter as small as 1 nm Length few nm to cm

CNT is configurationally equivalent to a two dimensional graphenesheet rolled into a tube

CNT exhibits1 Carrier mobility ~ 100000 cm2Vs2 Youngrsquos modulus over 1 Tera

Pascal as stiff as diamond3 Tensile strength ~ 200 GPa

Zigzag

Armchair

Chiral

MOLECULAR STRUCTUREMOLECULAR STRUCTURE

CNT can be metallic or semiconducting depending on chirality

Benchmarking CNT FETsBenchmarking CNT FETs

1

10

100

1000

10000

100000

130 90 65 45 22

Technology Node (nm)

Nor

mal

ized

FO

A

26X25X

28X 27X

Intrinsic CNT

MOS CNT FET

Band-edge SB CNTMidgap SB CNT

5000X

60X

50X20X

Si MOSFET

Source Ali Keshavarzi Intel

Nanotube Transistor ResearchNanotube Transistor ResearchGate

8nm HfO2

SiO2

p++ Si

PdPd CNT

Javey et al Nano Letters 4 1319 2004Delft Tans et al Nature 393 49 1998

Many people have studied individual nanotube transistors however the challenge is to integrate nanotube devices

Many people have studied individual nanotube transistors however the challenge is to integrate nanotube devices

Appenzeller et al PRL 93 19 2005

Drain

SourceGate

DrainSourceGate

Sapphire Substrate

GateOxide

Liu et al Nano Letters 6 34 2006

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes

Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes

SiSiO2

PMMA

Catalyst

CH4nanotube

Catalyst island

900 ordmC900 ordmC

metal electrode

H Dai et al Nature 395 878 (1998)

Infrastructure Nanotube CVD Generation IInfrastructure Nanotube CVD Generation I

1 μm

1 μm

26 nm in diameter

10 nm in diameter

High-quality nanotubes can be grown at specific positions

-60

-50

-40

-30

-20

-10

0

I DS(

nA)

-10-08-06-04-0200VDS(V)

Vg -4 V

0 V

2 V

6 V

Nanotube transistor can be easily produced

Si back gate

SiO2

S D

Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter

Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter

Carbon Nanotube Field-Effect Inverters X Liu R Lee J Han C Zhou Appl Phys Lett 79 3329 (2001)

One of the first integrated systems made of carbon nanotubes

Si back gate

K

Vin

Vout

VDD GND

p-type CNT n-type CNT

60

40

20

0

I DS(

nA)

-4 -2 0 2 4Vg(V)

VDS=10 mV

P type MOSFET12

8

4

0

I DS (

nA)

-4 -2 0 2 4Vg (V)

VDS=10 mV

N type MOSFET25

20

15

10

05

00

Vou

t(V)

252015100500Vin(V)

VDD=29 V

Vin Vout

0 V

VDD

p

n

Integrated Nanotube SystemsRing Oscillators Demonstrated by Avouris et al

Integrated Nanotube SystemsRing Oscillators Demonstrated by Avouris et al

Ph Avouris et al Science 311 1735 (2006)

Is there a way to assemble large quantities of nanotube devices

State-of-the-art of nanotube integration

Aligned Nanotubes for Devices and Circuits Aligned Nanotubes for Devices and Circuits

-- Project Mission Project Mission We want to tackle the challenging issue of We want to tackle the challenging issue of nanotube nanotube assembly and integrationassembly and integration

We want to grow carbon nanotubes withWe want to grow carbon nanotubes withControlled orientation (achieved by using Controlled orientation (achieved by using sapphire and quartz) sapphire and quartz) Controlled position (achieved) Controlled position (achieved) Controlled density (achieved) Controlled density (achieved) Controlled diameter (ongoing)Controlled diameter (ongoing)Controlled Controlled chiralitychirality (ongoing)(ongoing)

-- Our Approach Our Approach A novel nanotubeA novel nanotube--onon--insulator (NOI) insulator (NOI) approach based on approach based on aligned nanotubesaligned nanotubes for for integrated nanotube circuitsintegrated nanotube circuits Nanotube

devicesNanotube

circuits

Quartz SubstrateCatalyst Particle

Quartz Substrate

Nanotube

One of the first to grow aligned nanotubes on sapphireOne of the first to grow aligned nanotubes on sapphireJ of Am Chem Soc 127 5294 J of Am Chem Soc 127 5294 -- 5295 (2005) 5295 (2005)

The first to make aligned nanotube transistorsThe first to make aligned nanotube transistorsNano Letters 6 34Nano Letters 6 34--39 (2006)39 (2006)Reported by Reported by Scientific AmericanScientific American (April 2006 P16) (April 2006 P16)

The first to demonstrate waferThe first to demonstrate wafer--scale processing of aligned scale processing of aligned nanotube devices and circuitsnanotube devices and circuits

Logic circuits (CMOS inverter NAND NOR)Logic circuits (CMOS inverter NAND NOR)

The first to make transparent nanotube devicesThe first to make transparent nanotube devicesACS Nano in press (2008)ACS Nano in press (2008)

Chip

1

2

3

4

5

Our Achievements on Aligned Single-Walled NanotubesOur Achievements on Aligned SingleOur Achievements on Aligned Single--Walled NanotubesWalled Nanotubes

Synthesis of Aligned Nanotubes on Sapphire QuartzSynthesis of Aligned Nanotubes on Sapphire Quartz

Gas in

Gas out

Sapphire with catalyst

Substrate Sapphire quartzCatalyst FerritinTemperature 900degCGas flow rate

CH4 2000 sccmC2H4 10 sccmH2 800 sccm

Generation IIFull Wafer Production

Generation IIFull Wafer Production

50 μm

2 0

1 5

1 0

5N

umbe

r

2 01 0D iam e te r (nm)500 nm

134 plusmn 030 nm

1 All nanotubes grow normal to the c axis on a-plane sapphire2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin11 All nanotubes grow normal to the c axis on aAll nanotubes grow normal to the c axis on a--plane sapphireplane sapphire2 Narrow diameter distribution of 2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin

c axis

Aligned Nanotubes Grown on a-Plane SapphireAligned Nanotubes Grown on a-Plane Sapphire

Zhou et al JACS 127 5294 (2005)

Zhou Zhou et alet al Nano Letters Nano Letters (2006)(2006)(Top ten hot articles in 2006)

High density SWNTsUp to 40 nanotubes μmInter-nanotube spacing ~ 25 nm

Low density SWNTs

Control of Nanotube DensityControl of Nanotube Density

Zhou et al JACS 127 5294 (2005) Zhou Zhou et alet al Nano Letters (2006) Nano Letters (2006)

a-plane

Red spheres oxygen atomsBlue spheres aluminum atomsPurple plane a-plane orientation

Hypothetic Schematic Diagram of SWNT on a-Plane SapphireHypothetic Schematic Diagram of SWNT on a-Plane Sapphire

Calculation of Lennard-Jones Potential Calculation of Lennard-Jones Potential

sumsum⎥⎥⎥

⎦

⎤

⎢⎢⎢

⎣

⎡

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

minusminus⎟

⎟

⎠

⎞

⎜⎜

⎝

⎛

minus+

⎥⎥

⎦

⎤

⎢⎢

⎣

⎡

⎟⎟⎠

⎞⎜⎜⎝

⎛

minusminus⎟

⎟⎠

⎞⎜⎜⎝

⎛

minus=

j j

CAl

j

CAlCAl

i i

CO

i

COCO rrrrrrrr

rU

612612

44)( vvvvvvvvv σσ

εσσ

ε

a carbon atom and oxygen atoms in sapphire

a carbon atom and oxygen atoms in sapphire

a carbon atom and Al atoms in sapphire

a carbon atom and Al atoms in sapphire

Interaction between

Interaction between

C-plane C-plane a-plane a-plane

Potential wellPotential wellZhou Zhou et alet al JPCC JPCC 112 15929 (200(20088))

Synthesis of Nanotubes with Controlled Orientations and Positions

Synthesis of Nanotubes with Controlled Orientations and Positions

Catalyst

Photo Resist

QuartzSapphire

Catalyst Island

Aligned NanotubesMetal Electrode

SD

G

Dielectric Layer

3-10 nanotubes microm

Aligned Nanotubes on Quartz Using Patterned CatalystAligned Nanotubes on Quartz Using Patterned Catalystcatalyst

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

(a)

Poly Si Gate

Gate Oxide

SourceDrain Electrode

(b)

NanotubeGate Dielectric

Gate

SourceDrain Electrode

Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)

Comparison between SiliconComparison between Silicon--onon--insulator (SOI) and insulator (SOI) and NanotubeNanotube--onon--Insulator (NOI)Insulator (NOI)

SOISOISOI NOINOINOI

Common Features1 Active material (Si or SWNT) is all over the surface2 Many devices can be patterned anywhere on the substrate3 Unwanted silicon or SWNTs can be removed via etching4 SOI and NOI offer minimized parasitic capacitance faster switching speed

and lower dynamic power consumption

Common FeaturesCommon Features11 Active material (Si or SWNT) is all over the surfaceActive material (Si or SWNT) is all over the surface22 Many devices can be patterned anywhere on the substrateMany devices can be patterned anywhere on the substrate33 Unwanted silicon or Unwanted silicon or SWNTsSWNTs can be removed via etchingcan be removed via etching44 SOI and NOI offer minimized parasitic capacitance faster switchSOI and NOI offer minimized parasitic capacitance faster switching speed ing speed

and lower dynamic power consumptionand lower dynamic power consumption Zhou et al Nano Letters (2006)

a-Sapphire

Wafer-Scale Aligned Nanotube SynthesisWafer-Scale Aligned Nanotube Synthesis

1200

1000

800

600

400

200

Tem

pera

ture

200150100500

Time (min)

Growth Annealing

Key meticulous temperature control amp uniform growth

1μm

Quartz 1000

800

600

400

200Tem

pera

ture

6004002000

Time (min)

Growth Annealing

1μm

4 inch substrate

Gas in

Gas out

Quartz or Sapphire with patterned

catalyst

9 feet-long growth furnace with three-zone

Wafer-Scale CNT TransferWafer-Scale CNT TransferTransfer fullTransfer full--wafer of wafer of CNTsCNTs from quartz growth substrate to SiOfrom quartz growth substrate to SiO22Si fabrication Si fabrication

substrate substrate allows largeallows large--scale integrationscale integration

Nano Lett 9 189ndash197 20094

Wafer-Scale Aligned Nanotube Device FabricationWafer-Scale Aligned Nanotube Device Fabrication

Back-Gated Submicron TransistorsBack-Gated Submicron Transistors

Back-gated transistors

1 microm

L = 1 microm

1 microm

L = 075 microm

1 microm

L = 05 microm

I-Vg curves Channel length dependence

-120

-100

-80

-60

-40

-20

0

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

-60

-40

-20

0

I ds (μ

Α)

-1500Vds (V)

-1 V

-08 V

-06 V

-04 V

-02 V

Vg from -8V to 8V

15

10

05

I ds (m

A)

-10 -5 0 5 10Vg (V)

L = 05 microm L = 075 microm L = 1 microm L = 2 microm L = 5 microm L = 10 microm L = 20 microm

80

60

40

20

gm

(μ S

)

5 6 7 81

2 3 4 5 6 7 810

2

L(μm)

2

4

6810-6

2

4

6810-5

I DW

(mA

microm

) gm

Ion Ioff

Top-gated transistors

075 μmG

S

D

Al2O3

15

10

5

0

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

10-8

10-7

10-6

10-5

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

15

10

5

0

-5

-10

-15

I ds (μ

Α)

-10 -05 00 05 10Vds (V)

I-Vg curves I-Vds curves

Top-Gated Submicron TransistorsTop-Gated Submicron Transistors

N-type nanotube transistorsN-type nanotube transistorsHydrazine(NHydrazine(N22HH44) doping) doping

12

10

08

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds =01 V Vds =03 V Vds =05 V Vds =07 V Vds =09 V Vds =11 V

Before

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds=01 VVds=03 VVds=05VVds=07 VVds=09 VVds=11 V

After

Gain asymp54

10

08

06

04

02

00

Vou

t (V)

50454035302520

Vin (V)

6

5

4

3

2

1

0

I (nA)

Vout

I

Inverter

Gain =54

K doping

10

8

6

4

2

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

Before K doping After K doping

Gain asymp 5

p-type

n-type

15

10

05

00V

out (

V)

252015100500

Vin (V)

Gain=5

Potassium Doping and CMOS InverterPotassium Doping and CMOS Inverter

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

CMOS NAND amp NORCMOS NAND amp NORIndividual back-gated

NOR NAND

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

10 μm 10 μm10 μm

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Zigzag

Armchair

Chiral

MOLECULAR STRUCTUREMOLECULAR STRUCTURE

CNT can be metallic or semiconducting depending on chirality

Benchmarking CNT FETsBenchmarking CNT FETs

1

10

100

1000

10000

100000

130 90 65 45 22

Technology Node (nm)

Nor

mal

ized

FO

A

26X25X

28X 27X

Intrinsic CNT

MOS CNT FET

Band-edge SB CNTMidgap SB CNT

5000X

60X

50X20X

Si MOSFET

Source Ali Keshavarzi Intel

Nanotube Transistor ResearchNanotube Transistor ResearchGate

8nm HfO2

SiO2

p++ Si

PdPd CNT

Javey et al Nano Letters 4 1319 2004Delft Tans et al Nature 393 49 1998

Many people have studied individual nanotube transistors however the challenge is to integrate nanotube devices

Many people have studied individual nanotube transistors however the challenge is to integrate nanotube devices

Appenzeller et al PRL 93 19 2005

Drain

SourceGate

DrainSourceGate

Sapphire Substrate

GateOxide

Liu et al Nano Letters 6 34 2006

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes

Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes

SiSiO2

PMMA

Catalyst

CH4nanotube

Catalyst island

900 ordmC900 ordmC

metal electrode

H Dai et al Nature 395 878 (1998)

Infrastructure Nanotube CVD Generation IInfrastructure Nanotube CVD Generation I

1 μm

1 μm

26 nm in diameter

10 nm in diameter

High-quality nanotubes can be grown at specific positions

-60

-50

-40

-30

-20

-10

0

I DS(

nA)

-10-08-06-04-0200VDS(V)

Vg -4 V

0 V

2 V

6 V

Nanotube transistor can be easily produced

Si back gate

SiO2

S D

Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter

Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter

Carbon Nanotube Field-Effect Inverters X Liu R Lee J Han C Zhou Appl Phys Lett 79 3329 (2001)

One of the first integrated systems made of carbon nanotubes

Si back gate

K

Vin

Vout

VDD GND

p-type CNT n-type CNT

60

40

20

0

I DS(

nA)

-4 -2 0 2 4Vg(V)

VDS=10 mV

P type MOSFET12

8

4

0

I DS (

nA)

-4 -2 0 2 4Vg (V)

VDS=10 mV

N type MOSFET25

20

15

10

05

00

Vou

t(V)

252015100500Vin(V)

VDD=29 V

Vin Vout

0 V

VDD

p

n

Integrated Nanotube SystemsRing Oscillators Demonstrated by Avouris et al

Integrated Nanotube SystemsRing Oscillators Demonstrated by Avouris et al

Ph Avouris et al Science 311 1735 (2006)

Is there a way to assemble large quantities of nanotube devices

State-of-the-art of nanotube integration

Aligned Nanotubes for Devices and Circuits Aligned Nanotubes for Devices and Circuits

-- Project Mission Project Mission We want to tackle the challenging issue of We want to tackle the challenging issue of nanotube nanotube assembly and integrationassembly and integration

We want to grow carbon nanotubes withWe want to grow carbon nanotubes withControlled orientation (achieved by using Controlled orientation (achieved by using sapphire and quartz) sapphire and quartz) Controlled position (achieved) Controlled position (achieved) Controlled density (achieved) Controlled density (achieved) Controlled diameter (ongoing)Controlled diameter (ongoing)Controlled Controlled chiralitychirality (ongoing)(ongoing)

-- Our Approach Our Approach A novel nanotubeA novel nanotube--onon--insulator (NOI) insulator (NOI) approach based on approach based on aligned nanotubesaligned nanotubes for for integrated nanotube circuitsintegrated nanotube circuits Nanotube

devicesNanotube

circuits

Quartz SubstrateCatalyst Particle

Quartz Substrate

Nanotube

One of the first to grow aligned nanotubes on sapphireOne of the first to grow aligned nanotubes on sapphireJ of Am Chem Soc 127 5294 J of Am Chem Soc 127 5294 -- 5295 (2005) 5295 (2005)

The first to make aligned nanotube transistorsThe first to make aligned nanotube transistorsNano Letters 6 34Nano Letters 6 34--39 (2006)39 (2006)Reported by Reported by Scientific AmericanScientific American (April 2006 P16) (April 2006 P16)

The first to demonstrate waferThe first to demonstrate wafer--scale processing of aligned scale processing of aligned nanotube devices and circuitsnanotube devices and circuits

Logic circuits (CMOS inverter NAND NOR)Logic circuits (CMOS inverter NAND NOR)

The first to make transparent nanotube devicesThe first to make transparent nanotube devicesACS Nano in press (2008)ACS Nano in press (2008)

Chip

1

2

3

4

5

Our Achievements on Aligned Single-Walled NanotubesOur Achievements on Aligned SingleOur Achievements on Aligned Single--Walled NanotubesWalled Nanotubes

Synthesis of Aligned Nanotubes on Sapphire QuartzSynthesis of Aligned Nanotubes on Sapphire Quartz

Gas in

Gas out

Sapphire with catalyst

Substrate Sapphire quartzCatalyst FerritinTemperature 900degCGas flow rate

CH4 2000 sccmC2H4 10 sccmH2 800 sccm

Generation IIFull Wafer Production

Generation IIFull Wafer Production

50 μm

2 0

1 5

1 0

5N

umbe

r

2 01 0D iam e te r (nm)500 nm

134 plusmn 030 nm

1 All nanotubes grow normal to the c axis on a-plane sapphire2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin11 All nanotubes grow normal to the c axis on aAll nanotubes grow normal to the c axis on a--plane sapphireplane sapphire2 Narrow diameter distribution of 2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin

c axis

Aligned Nanotubes Grown on a-Plane SapphireAligned Nanotubes Grown on a-Plane Sapphire

Zhou et al JACS 127 5294 (2005)

Zhou Zhou et alet al Nano Letters Nano Letters (2006)(2006)(Top ten hot articles in 2006)

High density SWNTsUp to 40 nanotubes μmInter-nanotube spacing ~ 25 nm

Low density SWNTs

Control of Nanotube DensityControl of Nanotube Density

Zhou et al JACS 127 5294 (2005) Zhou Zhou et alet al Nano Letters (2006) Nano Letters (2006)

a-plane

Red spheres oxygen atomsBlue spheres aluminum atomsPurple plane a-plane orientation

Hypothetic Schematic Diagram of SWNT on a-Plane SapphireHypothetic Schematic Diagram of SWNT on a-Plane Sapphire

Calculation of Lennard-Jones Potential Calculation of Lennard-Jones Potential

sumsum⎥⎥⎥

⎦

⎤

⎢⎢⎢

⎣

⎡

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

minusminus⎟

⎟

⎠

⎞

⎜⎜

⎝

⎛

minus+

⎥⎥

⎦

⎤

⎢⎢

⎣

⎡

⎟⎟⎠

⎞⎜⎜⎝

⎛

minusminus⎟

⎟⎠

⎞⎜⎜⎝

⎛

minus=

j j

CAl

j

CAlCAl

i i

CO

i

COCO rrrrrrrr

rU

612612

44)( vvvvvvvvv σσ

εσσ

ε

a carbon atom and oxygen atoms in sapphire

a carbon atom and oxygen atoms in sapphire

a carbon atom and Al atoms in sapphire

a carbon atom and Al atoms in sapphire

Interaction between

Interaction between

C-plane C-plane a-plane a-plane

Potential wellPotential wellZhou Zhou et alet al JPCC JPCC 112 15929 (200(20088))

Synthesis of Nanotubes with Controlled Orientations and Positions

Synthesis of Nanotubes with Controlled Orientations and Positions

Catalyst

Photo Resist

QuartzSapphire

Catalyst Island

Aligned NanotubesMetal Electrode

SD

G

Dielectric Layer

3-10 nanotubes microm

Aligned Nanotubes on Quartz Using Patterned CatalystAligned Nanotubes on Quartz Using Patterned Catalystcatalyst

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

(a)

Poly Si Gate

Gate Oxide

SourceDrain Electrode

(b)

NanotubeGate Dielectric

Gate

SourceDrain Electrode

Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)

Comparison between SiliconComparison between Silicon--onon--insulator (SOI) and insulator (SOI) and NanotubeNanotube--onon--Insulator (NOI)Insulator (NOI)

SOISOISOI NOINOINOI

Common Features1 Active material (Si or SWNT) is all over the surface2 Many devices can be patterned anywhere on the substrate3 Unwanted silicon or SWNTs can be removed via etching4 SOI and NOI offer minimized parasitic capacitance faster switching speed

and lower dynamic power consumption

Common FeaturesCommon Features11 Active material (Si or SWNT) is all over the surfaceActive material (Si or SWNT) is all over the surface22 Many devices can be patterned anywhere on the substrateMany devices can be patterned anywhere on the substrate33 Unwanted silicon or Unwanted silicon or SWNTsSWNTs can be removed via etchingcan be removed via etching44 SOI and NOI offer minimized parasitic capacitance faster switchSOI and NOI offer minimized parasitic capacitance faster switching speed ing speed

and lower dynamic power consumptionand lower dynamic power consumption Zhou et al Nano Letters (2006)

a-Sapphire

Wafer-Scale Aligned Nanotube SynthesisWafer-Scale Aligned Nanotube Synthesis

1200

1000

800

600

400

200

Tem

pera

ture

200150100500

Time (min)

Growth Annealing

Key meticulous temperature control amp uniform growth

1μm

Quartz 1000

800

600

400

200Tem

pera

ture

6004002000

Time (min)

Growth Annealing

1μm

4 inch substrate

Gas in

Gas out

Quartz or Sapphire with patterned

catalyst

9 feet-long growth furnace with three-zone

Wafer-Scale CNT TransferWafer-Scale CNT TransferTransfer fullTransfer full--wafer of wafer of CNTsCNTs from quartz growth substrate to SiOfrom quartz growth substrate to SiO22Si fabrication Si fabrication

substrate substrate allows largeallows large--scale integrationscale integration

Nano Lett 9 189ndash197 20094

Wafer-Scale Aligned Nanotube Device FabricationWafer-Scale Aligned Nanotube Device Fabrication

Back-Gated Submicron TransistorsBack-Gated Submicron Transistors

Back-gated transistors

1 microm

L = 1 microm

1 microm

L = 075 microm

1 microm

L = 05 microm

I-Vg curves Channel length dependence

-120

-100

-80

-60

-40

-20

0

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

-60

-40

-20

0

I ds (μ

Α)

-1500Vds (V)

-1 V

-08 V

-06 V

-04 V

-02 V

Vg from -8V to 8V

15

10

05

I ds (m

A)

-10 -5 0 5 10Vg (V)

L = 05 microm L = 075 microm L = 1 microm L = 2 microm L = 5 microm L = 10 microm L = 20 microm

80

60

40

20

gm

(μ S

)

5 6 7 81

2 3 4 5 6 7 810

2

L(μm)

2

4

6810-6

2

4

6810-5

I DW

(mA

microm

) gm

Ion Ioff

Top-gated transistors

075 μmG

S

D

Al2O3

15

10

5

0

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

10-8

10-7

10-6

10-5

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

15

10

5

0

-5

-10

-15

I ds (μ

Α)

-10 -05 00 05 10Vds (V)

I-Vg curves I-Vds curves

Top-Gated Submicron TransistorsTop-Gated Submicron Transistors

N-type nanotube transistorsN-type nanotube transistorsHydrazine(NHydrazine(N22HH44) doping) doping

12

10

08

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds =01 V Vds =03 V Vds =05 V Vds =07 V Vds =09 V Vds =11 V

Before

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds=01 VVds=03 VVds=05VVds=07 VVds=09 VVds=11 V

After

Gain asymp54

10

08

06

04

02

00

Vou

t (V)

50454035302520

Vin (V)

6

5

4

3

2

1

0

I (nA)

Vout

I

Inverter

Gain =54

K doping

10

8

6

4

2

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

Before K doping After K doping

Gain asymp 5

p-type

n-type

15

10

05

00V

out (

V)

252015100500

Vin (V)

Gain=5

Potassium Doping and CMOS InverterPotassium Doping and CMOS Inverter

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

CMOS NAND amp NORCMOS NAND amp NORIndividual back-gated

NOR NAND

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

10 μm 10 μm10 μm

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Benchmarking CNT FETsBenchmarking CNT FETs

1

10

100

1000

10000

100000

130 90 65 45 22

Technology Node (nm)

Nor

mal

ized

FO

A

26X25X

28X 27X

Intrinsic CNT

MOS CNT FET

Band-edge SB CNTMidgap SB CNT

5000X

60X

50X20X

Si MOSFET

Source Ali Keshavarzi Intel

Nanotube Transistor ResearchNanotube Transistor ResearchGate

8nm HfO2

SiO2

p++ Si

PdPd CNT

Javey et al Nano Letters 4 1319 2004Delft Tans et al Nature 393 49 1998

Many people have studied individual nanotube transistors however the challenge is to integrate nanotube devices

Many people have studied individual nanotube transistors however the challenge is to integrate nanotube devices

Appenzeller et al PRL 93 19 2005

Drain

SourceGate

DrainSourceGate

Sapphire Substrate

GateOxide

Liu et al Nano Letters 6 34 2006

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes

Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes

SiSiO2

PMMA

Catalyst

CH4nanotube

Catalyst island

900 ordmC900 ordmC

metal electrode

H Dai et al Nature 395 878 (1998)

Infrastructure Nanotube CVD Generation IInfrastructure Nanotube CVD Generation I

1 μm

1 μm

26 nm in diameter

10 nm in diameter

High-quality nanotubes can be grown at specific positions

-60

-50

-40

-30

-20

-10

0

I DS(

nA)

-10-08-06-04-0200VDS(V)

Vg -4 V

0 V

2 V

6 V

Nanotube transistor can be easily produced

Si back gate

SiO2

S D

Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter

Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter

Carbon Nanotube Field-Effect Inverters X Liu R Lee J Han C Zhou Appl Phys Lett 79 3329 (2001)

One of the first integrated systems made of carbon nanotubes

Si back gate

K

Vin

Vout

VDD GND

p-type CNT n-type CNT

60

40

20

0

I DS(

nA)

-4 -2 0 2 4Vg(V)

VDS=10 mV

P type MOSFET12

8

4

0

I DS (

nA)

-4 -2 0 2 4Vg (V)

VDS=10 mV

N type MOSFET25

20

15

10

05

00

Vou

t(V)

252015100500Vin(V)

VDD=29 V

Vin Vout

0 V

VDD

p

n

Integrated Nanotube SystemsRing Oscillators Demonstrated by Avouris et al

Integrated Nanotube SystemsRing Oscillators Demonstrated by Avouris et al

Ph Avouris et al Science 311 1735 (2006)

Is there a way to assemble large quantities of nanotube devices

State-of-the-art of nanotube integration

Aligned Nanotubes for Devices and Circuits Aligned Nanotubes for Devices and Circuits

-- Project Mission Project Mission We want to tackle the challenging issue of We want to tackle the challenging issue of nanotube nanotube assembly and integrationassembly and integration

We want to grow carbon nanotubes withWe want to grow carbon nanotubes withControlled orientation (achieved by using Controlled orientation (achieved by using sapphire and quartz) sapphire and quartz) Controlled position (achieved) Controlled position (achieved) Controlled density (achieved) Controlled density (achieved) Controlled diameter (ongoing)Controlled diameter (ongoing)Controlled Controlled chiralitychirality (ongoing)(ongoing)

-- Our Approach Our Approach A novel nanotubeA novel nanotube--onon--insulator (NOI) insulator (NOI) approach based on approach based on aligned nanotubesaligned nanotubes for for integrated nanotube circuitsintegrated nanotube circuits Nanotube

devicesNanotube

circuits

Quartz SubstrateCatalyst Particle

Quartz Substrate

Nanotube

One of the first to grow aligned nanotubes on sapphireOne of the first to grow aligned nanotubes on sapphireJ of Am Chem Soc 127 5294 J of Am Chem Soc 127 5294 -- 5295 (2005) 5295 (2005)

The first to make aligned nanotube transistorsThe first to make aligned nanotube transistorsNano Letters 6 34Nano Letters 6 34--39 (2006)39 (2006)Reported by Reported by Scientific AmericanScientific American (April 2006 P16) (April 2006 P16)

The first to demonstrate waferThe first to demonstrate wafer--scale processing of aligned scale processing of aligned nanotube devices and circuitsnanotube devices and circuits

Logic circuits (CMOS inverter NAND NOR)Logic circuits (CMOS inverter NAND NOR)

The first to make transparent nanotube devicesThe first to make transparent nanotube devicesACS Nano in press (2008)ACS Nano in press (2008)

Chip

1

2

3

4

5

Our Achievements on Aligned Single-Walled NanotubesOur Achievements on Aligned SingleOur Achievements on Aligned Single--Walled NanotubesWalled Nanotubes

Synthesis of Aligned Nanotubes on Sapphire QuartzSynthesis of Aligned Nanotubes on Sapphire Quartz

Gas in

Gas out

Sapphire with catalyst

Substrate Sapphire quartzCatalyst FerritinTemperature 900degCGas flow rate

CH4 2000 sccmC2H4 10 sccmH2 800 sccm

Generation IIFull Wafer Production

Generation IIFull Wafer Production

50 μm

2 0

1 5

1 0

5N

umbe

r

2 01 0D iam e te r (nm)500 nm

134 plusmn 030 nm

1 All nanotubes grow normal to the c axis on a-plane sapphire2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin11 All nanotubes grow normal to the c axis on aAll nanotubes grow normal to the c axis on a--plane sapphireplane sapphire2 Narrow diameter distribution of 2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin

c axis

Aligned Nanotubes Grown on a-Plane SapphireAligned Nanotubes Grown on a-Plane Sapphire

Zhou et al JACS 127 5294 (2005)

Zhou Zhou et alet al Nano Letters Nano Letters (2006)(2006)(Top ten hot articles in 2006)

High density SWNTsUp to 40 nanotubes μmInter-nanotube spacing ~ 25 nm

Low density SWNTs

Control of Nanotube DensityControl of Nanotube Density

Zhou et al JACS 127 5294 (2005) Zhou Zhou et alet al Nano Letters (2006) Nano Letters (2006)

a-plane

Red spheres oxygen atomsBlue spheres aluminum atomsPurple plane a-plane orientation

Hypothetic Schematic Diagram of SWNT on a-Plane SapphireHypothetic Schematic Diagram of SWNT on a-Plane Sapphire

Calculation of Lennard-Jones Potential Calculation of Lennard-Jones Potential

sumsum⎥⎥⎥

⎦

⎤

⎢⎢⎢

⎣

⎡

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

minusminus⎟

⎟

⎠

⎞

⎜⎜

⎝

⎛

minus+

⎥⎥

⎦

⎤

⎢⎢

⎣

⎡

⎟⎟⎠

⎞⎜⎜⎝

⎛

minusminus⎟

⎟⎠

⎞⎜⎜⎝

⎛

minus=

j j

CAl

j

CAlCAl

i i

CO

i

COCO rrrrrrrr

rU

612612

44)( vvvvvvvvv σσ

εσσ

ε

a carbon atom and oxygen atoms in sapphire

a carbon atom and oxygen atoms in sapphire

a carbon atom and Al atoms in sapphire

a carbon atom and Al atoms in sapphire

Interaction between

Interaction between

C-plane C-plane a-plane a-plane

Potential wellPotential wellZhou Zhou et alet al JPCC JPCC 112 15929 (200(20088))

Synthesis of Nanotubes with Controlled Orientations and Positions

Synthesis of Nanotubes with Controlled Orientations and Positions

Catalyst

Photo Resist

QuartzSapphire

Catalyst Island

Aligned NanotubesMetal Electrode

SD

G

Dielectric Layer

3-10 nanotubes microm

Aligned Nanotubes on Quartz Using Patterned CatalystAligned Nanotubes on Quartz Using Patterned Catalystcatalyst

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

(a)

Poly Si Gate

Gate Oxide

SourceDrain Electrode

(b)

NanotubeGate Dielectric

Gate

SourceDrain Electrode

Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)

Comparison between SiliconComparison between Silicon--onon--insulator (SOI) and insulator (SOI) and NanotubeNanotube--onon--Insulator (NOI)Insulator (NOI)

SOISOISOI NOINOINOI

Common Features1 Active material (Si or SWNT) is all over the surface2 Many devices can be patterned anywhere on the substrate3 Unwanted silicon or SWNTs can be removed via etching4 SOI and NOI offer minimized parasitic capacitance faster switching speed

and lower dynamic power consumption

Common FeaturesCommon Features11 Active material (Si or SWNT) is all over the surfaceActive material (Si or SWNT) is all over the surface22 Many devices can be patterned anywhere on the substrateMany devices can be patterned anywhere on the substrate33 Unwanted silicon or Unwanted silicon or SWNTsSWNTs can be removed via etchingcan be removed via etching44 SOI and NOI offer minimized parasitic capacitance faster switchSOI and NOI offer minimized parasitic capacitance faster switching speed ing speed

and lower dynamic power consumptionand lower dynamic power consumption Zhou et al Nano Letters (2006)

a-Sapphire

Wafer-Scale Aligned Nanotube SynthesisWafer-Scale Aligned Nanotube Synthesis

1200

1000

800

600

400

200

Tem

pera

ture

200150100500

Time (min)

Growth Annealing

Key meticulous temperature control amp uniform growth

1μm

Quartz 1000

800

600

400

200Tem

pera

ture

6004002000

Time (min)

Growth Annealing

1μm

4 inch substrate

Gas in

Gas out

Quartz or Sapphire with patterned

catalyst

9 feet-long growth furnace with three-zone

Wafer-Scale CNT TransferWafer-Scale CNT TransferTransfer fullTransfer full--wafer of wafer of CNTsCNTs from quartz growth substrate to SiOfrom quartz growth substrate to SiO22Si fabrication Si fabrication

substrate substrate allows largeallows large--scale integrationscale integration

Nano Lett 9 189ndash197 20094

Wafer-Scale Aligned Nanotube Device FabricationWafer-Scale Aligned Nanotube Device Fabrication

Back-Gated Submicron TransistorsBack-Gated Submicron Transistors

Back-gated transistors

1 microm

L = 1 microm

1 microm

L = 075 microm

1 microm

L = 05 microm

I-Vg curves Channel length dependence

-120

-100

-80

-60

-40

-20

0

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

-60

-40

-20

0

I ds (μ

Α)

-1500Vds (V)

-1 V

-08 V

-06 V

-04 V

-02 V

Vg from -8V to 8V

15

10

05

I ds (m

A)

-10 -5 0 5 10Vg (V)

L = 05 microm L = 075 microm L = 1 microm L = 2 microm L = 5 microm L = 10 microm L = 20 microm

80

60

40

20

gm

(μ S

)

5 6 7 81

2 3 4 5 6 7 810

2

L(μm)

2

4

6810-6

2

4

6810-5

I DW

(mA

microm

) gm

Ion Ioff

Top-gated transistors

075 μmG

S

D

Al2O3

15

10

5

0

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

10-8

10-7

10-6

10-5

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

15

10

5

0

-5

-10

-15

I ds (μ

Α)

-10 -05 00 05 10Vds (V)

I-Vg curves I-Vds curves

Top-Gated Submicron TransistorsTop-Gated Submicron Transistors

N-type nanotube transistorsN-type nanotube transistorsHydrazine(NHydrazine(N22HH44) doping) doping

12

10

08

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds =01 V Vds =03 V Vds =05 V Vds =07 V Vds =09 V Vds =11 V

Before

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds=01 VVds=03 VVds=05VVds=07 VVds=09 VVds=11 V

After

Gain asymp54

10

08

06

04

02

00

Vou

t (V)

50454035302520

Vin (V)

6

5

4

3

2

1

0

I (nA)

Vout

I

Inverter

Gain =54

K doping

10

8

6

4

2

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

Before K doping After K doping

Gain asymp 5

p-type

n-type

15

10

05

00V

out (

V)

252015100500

Vin (V)

Gain=5

Potassium Doping and CMOS InverterPotassium Doping and CMOS Inverter

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

CMOS NAND amp NORCMOS NAND amp NORIndividual back-gated

NOR NAND

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

10 μm 10 μm10 μm

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Nanotube Transistor ResearchNanotube Transistor ResearchGate

8nm HfO2

SiO2

p++ Si

PdPd CNT

Javey et al Nano Letters 4 1319 2004Delft Tans et al Nature 393 49 1998

Many people have studied individual nanotube transistors however the challenge is to integrate nanotube devices

Many people have studied individual nanotube transistors however the challenge is to integrate nanotube devices

Appenzeller et al PRL 93 19 2005

Drain

SourceGate

DrainSourceGate

Sapphire Substrate

GateOxide

Liu et al Nano Letters 6 34 2006

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes

Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes

SiSiO2

PMMA

Catalyst

CH4nanotube

Catalyst island

900 ordmC900 ordmC

metal electrode

H Dai et al Nature 395 878 (1998)

Infrastructure Nanotube CVD Generation IInfrastructure Nanotube CVD Generation I

1 μm

1 μm

26 nm in diameter

10 nm in diameter

High-quality nanotubes can be grown at specific positions

-60

-50

-40

-30

-20

-10

0

I DS(

nA)

-10-08-06-04-0200VDS(V)

Vg -4 V

0 V

2 V

6 V

Nanotube transistor can be easily produced

Si back gate

SiO2

S D

Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter

Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter

Carbon Nanotube Field-Effect Inverters X Liu R Lee J Han C Zhou Appl Phys Lett 79 3329 (2001)

One of the first integrated systems made of carbon nanotubes

Si back gate

K

Vin

Vout

VDD GND

p-type CNT n-type CNT

60

40

20

0

I DS(

nA)

-4 -2 0 2 4Vg(V)

VDS=10 mV

P type MOSFET12

8

4

0

I DS (

nA)

-4 -2 0 2 4Vg (V)

VDS=10 mV

N type MOSFET25

20

15

10

05

00

Vou

t(V)

252015100500Vin(V)

VDD=29 V

Vin Vout

0 V

VDD

p

n

Integrated Nanotube SystemsRing Oscillators Demonstrated by Avouris et al

Integrated Nanotube SystemsRing Oscillators Demonstrated by Avouris et al

Ph Avouris et al Science 311 1735 (2006)

Is there a way to assemble large quantities of nanotube devices

State-of-the-art of nanotube integration

Aligned Nanotubes for Devices and Circuits Aligned Nanotubes for Devices and Circuits

-- Project Mission Project Mission We want to tackle the challenging issue of We want to tackle the challenging issue of nanotube nanotube assembly and integrationassembly and integration

We want to grow carbon nanotubes withWe want to grow carbon nanotubes withControlled orientation (achieved by using Controlled orientation (achieved by using sapphire and quartz) sapphire and quartz) Controlled position (achieved) Controlled position (achieved) Controlled density (achieved) Controlled density (achieved) Controlled diameter (ongoing)Controlled diameter (ongoing)Controlled Controlled chiralitychirality (ongoing)(ongoing)

-- Our Approach Our Approach A novel nanotubeA novel nanotube--onon--insulator (NOI) insulator (NOI) approach based on approach based on aligned nanotubesaligned nanotubes for for integrated nanotube circuitsintegrated nanotube circuits Nanotube

devicesNanotube

circuits

Quartz SubstrateCatalyst Particle

Quartz Substrate

Nanotube

One of the first to grow aligned nanotubes on sapphireOne of the first to grow aligned nanotubes on sapphireJ of Am Chem Soc 127 5294 J of Am Chem Soc 127 5294 -- 5295 (2005) 5295 (2005)

The first to make aligned nanotube transistorsThe first to make aligned nanotube transistorsNano Letters 6 34Nano Letters 6 34--39 (2006)39 (2006)Reported by Reported by Scientific AmericanScientific American (April 2006 P16) (April 2006 P16)

The first to demonstrate waferThe first to demonstrate wafer--scale processing of aligned scale processing of aligned nanotube devices and circuitsnanotube devices and circuits

Logic circuits (CMOS inverter NAND NOR)Logic circuits (CMOS inverter NAND NOR)

The first to make transparent nanotube devicesThe first to make transparent nanotube devicesACS Nano in press (2008)ACS Nano in press (2008)

Chip

1

2

3

4

5

Our Achievements on Aligned Single-Walled NanotubesOur Achievements on Aligned SingleOur Achievements on Aligned Single--Walled NanotubesWalled Nanotubes

Synthesis of Aligned Nanotubes on Sapphire QuartzSynthesis of Aligned Nanotubes on Sapphire Quartz

Gas in

Gas out

Sapphire with catalyst

Substrate Sapphire quartzCatalyst FerritinTemperature 900degCGas flow rate

CH4 2000 sccmC2H4 10 sccmH2 800 sccm

Generation IIFull Wafer Production

Generation IIFull Wafer Production

50 μm

2 0

1 5

1 0

5N

umbe

r

2 01 0D iam e te r (nm)500 nm

134 plusmn 030 nm

1 All nanotubes grow normal to the c axis on a-plane sapphire2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin11 All nanotubes grow normal to the c axis on aAll nanotubes grow normal to the c axis on a--plane sapphireplane sapphire2 Narrow diameter distribution of 2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin

c axis

Aligned Nanotubes Grown on a-Plane SapphireAligned Nanotubes Grown on a-Plane Sapphire

Zhou et al JACS 127 5294 (2005)

Zhou Zhou et alet al Nano Letters Nano Letters (2006)(2006)(Top ten hot articles in 2006)

High density SWNTsUp to 40 nanotubes μmInter-nanotube spacing ~ 25 nm

Low density SWNTs

Control of Nanotube DensityControl of Nanotube Density

Zhou et al JACS 127 5294 (2005) Zhou Zhou et alet al Nano Letters (2006) Nano Letters (2006)

a-plane

Red spheres oxygen atomsBlue spheres aluminum atomsPurple plane a-plane orientation

Hypothetic Schematic Diagram of SWNT on a-Plane SapphireHypothetic Schematic Diagram of SWNT on a-Plane Sapphire

Calculation of Lennard-Jones Potential Calculation of Lennard-Jones Potential

sumsum⎥⎥⎥

⎦

⎤

⎢⎢⎢

⎣

⎡

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

minusminus⎟

⎟

⎠

⎞

⎜⎜

⎝

⎛

minus+

⎥⎥

⎦

⎤

⎢⎢

⎣

⎡

⎟⎟⎠

⎞⎜⎜⎝

⎛

minusminus⎟

⎟⎠

⎞⎜⎜⎝

⎛

minus=

j j

CAl

j

CAlCAl

i i

CO

i

COCO rrrrrrrr

rU

612612

44)( vvvvvvvvv σσ

εσσ

ε

a carbon atom and oxygen atoms in sapphire

a carbon atom and oxygen atoms in sapphire

a carbon atom and Al atoms in sapphire

a carbon atom and Al atoms in sapphire

Interaction between

Interaction between

C-plane C-plane a-plane a-plane

Potential wellPotential wellZhou Zhou et alet al JPCC JPCC 112 15929 (200(20088))

Synthesis of Nanotubes with Controlled Orientations and Positions

Synthesis of Nanotubes with Controlled Orientations and Positions

Catalyst

Photo Resist

QuartzSapphire

Catalyst Island

Aligned NanotubesMetal Electrode

SD

G

Dielectric Layer

3-10 nanotubes microm

Aligned Nanotubes on Quartz Using Patterned CatalystAligned Nanotubes on Quartz Using Patterned Catalystcatalyst

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

(a)

Poly Si Gate

Gate Oxide

SourceDrain Electrode

(b)

NanotubeGate Dielectric

Gate

SourceDrain Electrode

Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)

Comparison between SiliconComparison between Silicon--onon--insulator (SOI) and insulator (SOI) and NanotubeNanotube--onon--Insulator (NOI)Insulator (NOI)

SOISOISOI NOINOINOI

Common Features1 Active material (Si or SWNT) is all over the surface2 Many devices can be patterned anywhere on the substrate3 Unwanted silicon or SWNTs can be removed via etching4 SOI and NOI offer minimized parasitic capacitance faster switching speed

and lower dynamic power consumption

Common FeaturesCommon Features11 Active material (Si or SWNT) is all over the surfaceActive material (Si or SWNT) is all over the surface22 Many devices can be patterned anywhere on the substrateMany devices can be patterned anywhere on the substrate33 Unwanted silicon or Unwanted silicon or SWNTsSWNTs can be removed via etchingcan be removed via etching44 SOI and NOI offer minimized parasitic capacitance faster switchSOI and NOI offer minimized parasitic capacitance faster switching speed ing speed

and lower dynamic power consumptionand lower dynamic power consumption Zhou et al Nano Letters (2006)

a-Sapphire

Wafer-Scale Aligned Nanotube SynthesisWafer-Scale Aligned Nanotube Synthesis

1200

1000

800

600

400

200

Tem

pera

ture

200150100500

Time (min)

Growth Annealing

Key meticulous temperature control amp uniform growth

1μm

Quartz 1000

800

600

400

200Tem

pera

ture

6004002000

Time (min)

Growth Annealing

1μm

4 inch substrate

Gas in

Gas out

Quartz or Sapphire with patterned

catalyst

9 feet-long growth furnace with three-zone

Wafer-Scale CNT TransferWafer-Scale CNT TransferTransfer fullTransfer full--wafer of wafer of CNTsCNTs from quartz growth substrate to SiOfrom quartz growth substrate to SiO22Si fabrication Si fabrication

substrate substrate allows largeallows large--scale integrationscale integration

Nano Lett 9 189ndash197 20094

Wafer-Scale Aligned Nanotube Device FabricationWafer-Scale Aligned Nanotube Device Fabrication

Back-Gated Submicron TransistorsBack-Gated Submicron Transistors

Back-gated transistors

1 microm

L = 1 microm

1 microm

L = 075 microm

1 microm

L = 05 microm

I-Vg curves Channel length dependence

-120

-100

-80

-60

-40

-20

0

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

-60

-40

-20

0

I ds (μ

Α)

-1500Vds (V)

-1 V

-08 V

-06 V

-04 V

-02 V

Vg from -8V to 8V

15

10

05

I ds (m

A)

-10 -5 0 5 10Vg (V)

L = 05 microm L = 075 microm L = 1 microm L = 2 microm L = 5 microm L = 10 microm L = 20 microm

80

60

40

20

gm

(μ S

)

5 6 7 81

2 3 4 5 6 7 810

2

L(μm)

2

4

6810-6

2

4

6810-5

I DW

(mA

microm

) gm

Ion Ioff

Top-gated transistors

075 μmG

S

D

Al2O3

15

10

5

0

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

10-8

10-7

10-6

10-5

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

15

10

5

0

-5

-10

-15

I ds (μ

Α)

-10 -05 00 05 10Vds (V)

I-Vg curves I-Vds curves

Top-Gated Submicron TransistorsTop-Gated Submicron Transistors

N-type nanotube transistorsN-type nanotube transistorsHydrazine(NHydrazine(N22HH44) doping) doping

12

10

08

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds =01 V Vds =03 V Vds =05 V Vds =07 V Vds =09 V Vds =11 V

Before

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds=01 VVds=03 VVds=05VVds=07 VVds=09 VVds=11 V

After

Gain asymp54

10

08

06

04

02

00

Vou

t (V)

50454035302520

Vin (V)

6

5

4

3

2

1

0

I (nA)

Vout

I

Inverter

Gain =54

K doping

10

8

6

4

2

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

Before K doping After K doping

Gain asymp 5

p-type

n-type

15

10

05

00V

out (

V)

252015100500

Vin (V)

Gain=5

Potassium Doping and CMOS InverterPotassium Doping and CMOS Inverter

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

CMOS NAND amp NORCMOS NAND amp NORIndividual back-gated

NOR NAND

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

10 μm 10 μm10 μm

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes

Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes

SiSiO2

PMMA

Catalyst

CH4nanotube

Catalyst island

900 ordmC900 ordmC

metal electrode

H Dai et al Nature 395 878 (1998)

Infrastructure Nanotube CVD Generation IInfrastructure Nanotube CVD Generation I

1 μm

1 μm

26 nm in diameter

10 nm in diameter

High-quality nanotubes can be grown at specific positions

-60

-50

-40

-30

-20

-10

0

I DS(

nA)

-10-08-06-04-0200VDS(V)

Vg -4 V

0 V

2 V

6 V

Nanotube transistor can be easily produced

Si back gate

SiO2

S D

Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter

Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter

Carbon Nanotube Field-Effect Inverters X Liu R Lee J Han C Zhou Appl Phys Lett 79 3329 (2001)

One of the first integrated systems made of carbon nanotubes

Si back gate

K

Vin

Vout

VDD GND

p-type CNT n-type CNT

60

40

20

0

I DS(

nA)

-4 -2 0 2 4Vg(V)

VDS=10 mV

P type MOSFET12

8

4

0

I DS (

nA)

-4 -2 0 2 4Vg (V)

VDS=10 mV

N type MOSFET25

20

15

10

05

00

Vou

t(V)

252015100500Vin(V)

VDD=29 V

Vin Vout

0 V

VDD

p

n

Integrated Nanotube SystemsRing Oscillators Demonstrated by Avouris et al

Integrated Nanotube SystemsRing Oscillators Demonstrated by Avouris et al

Ph Avouris et al Science 311 1735 (2006)

Is there a way to assemble large quantities of nanotube devices

State-of-the-art of nanotube integration

Aligned Nanotubes for Devices and Circuits Aligned Nanotubes for Devices and Circuits

-- Project Mission Project Mission We want to tackle the challenging issue of We want to tackle the challenging issue of nanotube nanotube assembly and integrationassembly and integration

We want to grow carbon nanotubes withWe want to grow carbon nanotubes withControlled orientation (achieved by using Controlled orientation (achieved by using sapphire and quartz) sapphire and quartz) Controlled position (achieved) Controlled position (achieved) Controlled density (achieved) Controlled density (achieved) Controlled diameter (ongoing)Controlled diameter (ongoing)Controlled Controlled chiralitychirality (ongoing)(ongoing)

-- Our Approach Our Approach A novel nanotubeA novel nanotube--onon--insulator (NOI) insulator (NOI) approach based on approach based on aligned nanotubesaligned nanotubes for for integrated nanotube circuitsintegrated nanotube circuits Nanotube

devicesNanotube

circuits

Quartz SubstrateCatalyst Particle

Quartz Substrate

Nanotube

One of the first to grow aligned nanotubes on sapphireOne of the first to grow aligned nanotubes on sapphireJ of Am Chem Soc 127 5294 J of Am Chem Soc 127 5294 -- 5295 (2005) 5295 (2005)

The first to make aligned nanotube transistorsThe first to make aligned nanotube transistorsNano Letters 6 34Nano Letters 6 34--39 (2006)39 (2006)Reported by Reported by Scientific AmericanScientific American (April 2006 P16) (April 2006 P16)

The first to demonstrate waferThe first to demonstrate wafer--scale processing of aligned scale processing of aligned nanotube devices and circuitsnanotube devices and circuits

Logic circuits (CMOS inverter NAND NOR)Logic circuits (CMOS inverter NAND NOR)

The first to make transparent nanotube devicesThe first to make transparent nanotube devicesACS Nano in press (2008)ACS Nano in press (2008)

Chip

1

2

3

4

5

Our Achievements on Aligned Single-Walled NanotubesOur Achievements on Aligned SingleOur Achievements on Aligned Single--Walled NanotubesWalled Nanotubes

Synthesis of Aligned Nanotubes on Sapphire QuartzSynthesis of Aligned Nanotubes on Sapphire Quartz

Gas in

Gas out

Sapphire with catalyst

Substrate Sapphire quartzCatalyst FerritinTemperature 900degCGas flow rate

CH4 2000 sccmC2H4 10 sccmH2 800 sccm

Generation IIFull Wafer Production

Generation IIFull Wafer Production

50 μm

2 0

1 5

1 0

5N

umbe

r

2 01 0D iam e te r (nm)500 nm

134 plusmn 030 nm

1 All nanotubes grow normal to the c axis on a-plane sapphire2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin11 All nanotubes grow normal to the c axis on aAll nanotubes grow normal to the c axis on a--plane sapphireplane sapphire2 Narrow diameter distribution of 2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin

c axis

Aligned Nanotubes Grown on a-Plane SapphireAligned Nanotubes Grown on a-Plane Sapphire

Zhou et al JACS 127 5294 (2005)

Zhou Zhou et alet al Nano Letters Nano Letters (2006)(2006)(Top ten hot articles in 2006)

High density SWNTsUp to 40 nanotubes μmInter-nanotube spacing ~ 25 nm

Low density SWNTs

Control of Nanotube DensityControl of Nanotube Density

Zhou et al JACS 127 5294 (2005) Zhou Zhou et alet al Nano Letters (2006) Nano Letters (2006)

a-plane

Red spheres oxygen atomsBlue spheres aluminum atomsPurple plane a-plane orientation

Hypothetic Schematic Diagram of SWNT on a-Plane SapphireHypothetic Schematic Diagram of SWNT on a-Plane Sapphire

Calculation of Lennard-Jones Potential Calculation of Lennard-Jones Potential

sumsum⎥⎥⎥

⎦

⎤

⎢⎢⎢

⎣

⎡

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

minusminus⎟

⎟

⎠

⎞

⎜⎜

⎝

⎛

minus+

⎥⎥

⎦

⎤

⎢⎢

⎣

⎡

⎟⎟⎠

⎞⎜⎜⎝

⎛

minusminus⎟

⎟⎠

⎞⎜⎜⎝

⎛

minus=

j j

CAl

j

CAlCAl

i i

CO

i

COCO rrrrrrrr

rU

612612

44)( vvvvvvvvv σσ

εσσ

ε

a carbon atom and oxygen atoms in sapphire

a carbon atom and oxygen atoms in sapphire

a carbon atom and Al atoms in sapphire

a carbon atom and Al atoms in sapphire

Interaction between

Interaction between

C-plane C-plane a-plane a-plane

Potential wellPotential wellZhou Zhou et alet al JPCC JPCC 112 15929 (200(20088))

Synthesis of Nanotubes with Controlled Orientations and Positions

Synthesis of Nanotubes with Controlled Orientations and Positions

Catalyst

Photo Resist

QuartzSapphire

Catalyst Island

Aligned NanotubesMetal Electrode

SD

G

Dielectric Layer

3-10 nanotubes microm

Aligned Nanotubes on Quartz Using Patterned CatalystAligned Nanotubes on Quartz Using Patterned Catalystcatalyst

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

(a)

Poly Si Gate

Gate Oxide

SourceDrain Electrode

(b)

NanotubeGate Dielectric

Gate

SourceDrain Electrode

Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)

Comparison between SiliconComparison between Silicon--onon--insulator (SOI) and insulator (SOI) and NanotubeNanotube--onon--Insulator (NOI)Insulator (NOI)

SOISOISOI NOINOINOI

Common Features1 Active material (Si or SWNT) is all over the surface2 Many devices can be patterned anywhere on the substrate3 Unwanted silicon or SWNTs can be removed via etching4 SOI and NOI offer minimized parasitic capacitance faster switching speed

and lower dynamic power consumption

Common FeaturesCommon Features11 Active material (Si or SWNT) is all over the surfaceActive material (Si or SWNT) is all over the surface22 Many devices can be patterned anywhere on the substrateMany devices can be patterned anywhere on the substrate33 Unwanted silicon or Unwanted silicon or SWNTsSWNTs can be removed via etchingcan be removed via etching44 SOI and NOI offer minimized parasitic capacitance faster switchSOI and NOI offer minimized parasitic capacitance faster switching speed ing speed

and lower dynamic power consumptionand lower dynamic power consumption Zhou et al Nano Letters (2006)

a-Sapphire

Wafer-Scale Aligned Nanotube SynthesisWafer-Scale Aligned Nanotube Synthesis

1200

1000

800

600

400

200

Tem

pera

ture

200150100500

Time (min)

Growth Annealing

Key meticulous temperature control amp uniform growth

1μm

Quartz 1000

800

600

400

200Tem

pera

ture

6004002000

Time (min)

Growth Annealing

1μm

4 inch substrate

Gas in

Gas out

Quartz or Sapphire with patterned

catalyst

9 feet-long growth furnace with three-zone

Wafer-Scale CNT TransferWafer-Scale CNT TransferTransfer fullTransfer full--wafer of wafer of CNTsCNTs from quartz growth substrate to SiOfrom quartz growth substrate to SiO22Si fabrication Si fabrication

substrate substrate allows largeallows large--scale integrationscale integration

Nano Lett 9 189ndash197 20094

Wafer-Scale Aligned Nanotube Device FabricationWafer-Scale Aligned Nanotube Device Fabrication

Back-Gated Submicron TransistorsBack-Gated Submicron Transistors

Back-gated transistors

1 microm

L = 1 microm

1 microm

L = 075 microm

1 microm

L = 05 microm

I-Vg curves Channel length dependence

-120

-100

-80

-60

-40

-20

0

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

-60

-40

-20

0

I ds (μ

Α)

-1500Vds (V)

-1 V

-08 V

-06 V

-04 V

-02 V

Vg from -8V to 8V

15

10

05

I ds (m

A)

-10 -5 0 5 10Vg (V)

L = 05 microm L = 075 microm L = 1 microm L = 2 microm L = 5 microm L = 10 microm L = 20 microm

80

60

40

20

gm

(μ S

)

5 6 7 81

2 3 4 5 6 7 810

2

L(μm)

2

4

6810-6

2

4

6810-5

I DW

(mA

microm

) gm

Ion Ioff

Top-gated transistors

075 μmG

S

D

Al2O3

15

10

5

0

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

10-8

10-7

10-6

10-5

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

15

10

5

0

-5

-10

-15

I ds (μ

Α)

-10 -05 00 05 10Vds (V)

I-Vg curves I-Vds curves

Top-Gated Submicron TransistorsTop-Gated Submicron Transistors

N-type nanotube transistorsN-type nanotube transistorsHydrazine(NHydrazine(N22HH44) doping) doping

12

10

08

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds =01 V Vds =03 V Vds =05 V Vds =07 V Vds =09 V Vds =11 V

Before

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds=01 VVds=03 VVds=05VVds=07 VVds=09 VVds=11 V

After

Gain asymp54

10

08

06

04

02

00

Vou

t (V)

50454035302520

Vin (V)

6

5

4

3

2

1

0

I (nA)

Vout

I

Inverter

Gain =54

K doping

10

8

6

4

2

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

Before K doping After K doping

Gain asymp 5

p-type

n-type

15

10

05

00V

out (

V)

252015100500

Vin (V)

Gain=5

Potassium Doping and CMOS InverterPotassium Doping and CMOS Inverter

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

CMOS NAND amp NORCMOS NAND amp NORIndividual back-gated

NOR NAND

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

10 μm 10 μm10 μm

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes

Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes

SiSiO2

PMMA

Catalyst

CH4nanotube

Catalyst island

900 ordmC900 ordmC

metal electrode

H Dai et al Nature 395 878 (1998)

Infrastructure Nanotube CVD Generation IInfrastructure Nanotube CVD Generation I

1 μm

1 μm

26 nm in diameter

10 nm in diameter

High-quality nanotubes can be grown at specific positions

-60

-50

-40

-30

-20

-10

0

I DS(

nA)

-10-08-06-04-0200VDS(V)

Vg -4 V

0 V

2 V

6 V

Nanotube transistor can be easily produced

Si back gate

SiO2

S D

Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter

Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter

Carbon Nanotube Field-Effect Inverters X Liu R Lee J Han C Zhou Appl Phys Lett 79 3329 (2001)

One of the first integrated systems made of carbon nanotubes

Si back gate

K

Vin

Vout

VDD GND

p-type CNT n-type CNT

60

40

20

0

I DS(

nA)

-4 -2 0 2 4Vg(V)

VDS=10 mV

P type MOSFET12

8

4

0

I DS (

nA)

-4 -2 0 2 4Vg (V)

VDS=10 mV

N type MOSFET25

20

15

10

05

00

Vou

t(V)

252015100500Vin(V)

VDD=29 V

Vin Vout

0 V

VDD

p

n

Integrated Nanotube SystemsRing Oscillators Demonstrated by Avouris et al

Integrated Nanotube SystemsRing Oscillators Demonstrated by Avouris et al

Ph Avouris et al Science 311 1735 (2006)

Is there a way to assemble large quantities of nanotube devices

State-of-the-art of nanotube integration

Aligned Nanotubes for Devices and Circuits Aligned Nanotubes for Devices and Circuits

-- Project Mission Project Mission We want to tackle the challenging issue of We want to tackle the challenging issue of nanotube nanotube assembly and integrationassembly and integration

We want to grow carbon nanotubes withWe want to grow carbon nanotubes withControlled orientation (achieved by using Controlled orientation (achieved by using sapphire and quartz) sapphire and quartz) Controlled position (achieved) Controlled position (achieved) Controlled density (achieved) Controlled density (achieved) Controlled diameter (ongoing)Controlled diameter (ongoing)Controlled Controlled chiralitychirality (ongoing)(ongoing)

-- Our Approach Our Approach A novel nanotubeA novel nanotube--onon--insulator (NOI) insulator (NOI) approach based on approach based on aligned nanotubesaligned nanotubes for for integrated nanotube circuitsintegrated nanotube circuits Nanotube

devicesNanotube

circuits

Quartz SubstrateCatalyst Particle

Quartz Substrate

Nanotube

One of the first to grow aligned nanotubes on sapphireOne of the first to grow aligned nanotubes on sapphireJ of Am Chem Soc 127 5294 J of Am Chem Soc 127 5294 -- 5295 (2005) 5295 (2005)

The first to make aligned nanotube transistorsThe first to make aligned nanotube transistorsNano Letters 6 34Nano Letters 6 34--39 (2006)39 (2006)Reported by Reported by Scientific AmericanScientific American (April 2006 P16) (April 2006 P16)

The first to demonstrate waferThe first to demonstrate wafer--scale processing of aligned scale processing of aligned nanotube devices and circuitsnanotube devices and circuits

Logic circuits (CMOS inverter NAND NOR)Logic circuits (CMOS inverter NAND NOR)

The first to make transparent nanotube devicesThe first to make transparent nanotube devicesACS Nano in press (2008)ACS Nano in press (2008)

Chip

1

2

3

4

5

Our Achievements on Aligned Single-Walled NanotubesOur Achievements on Aligned SingleOur Achievements on Aligned Single--Walled NanotubesWalled Nanotubes

Synthesis of Aligned Nanotubes on Sapphire QuartzSynthesis of Aligned Nanotubes on Sapphire Quartz

Gas in

Gas out

Sapphire with catalyst

Substrate Sapphire quartzCatalyst FerritinTemperature 900degCGas flow rate

CH4 2000 sccmC2H4 10 sccmH2 800 sccm

Generation IIFull Wafer Production

Generation IIFull Wafer Production

50 μm

2 0

1 5

1 0

5N

umbe

r

2 01 0D iam e te r (nm)500 nm

134 plusmn 030 nm

1 All nanotubes grow normal to the c axis on a-plane sapphire2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin11 All nanotubes grow normal to the c axis on aAll nanotubes grow normal to the c axis on a--plane sapphireplane sapphire2 Narrow diameter distribution of 2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin

c axis

Aligned Nanotubes Grown on a-Plane SapphireAligned Nanotubes Grown on a-Plane Sapphire

Zhou et al JACS 127 5294 (2005)

Zhou Zhou et alet al Nano Letters Nano Letters (2006)(2006)(Top ten hot articles in 2006)

High density SWNTsUp to 40 nanotubes μmInter-nanotube spacing ~ 25 nm

Low density SWNTs

Control of Nanotube DensityControl of Nanotube Density

Zhou et al JACS 127 5294 (2005) Zhou Zhou et alet al Nano Letters (2006) Nano Letters (2006)

a-plane

Red spheres oxygen atomsBlue spheres aluminum atomsPurple plane a-plane orientation

Hypothetic Schematic Diagram of SWNT on a-Plane SapphireHypothetic Schematic Diagram of SWNT on a-Plane Sapphire

Calculation of Lennard-Jones Potential Calculation of Lennard-Jones Potential

sumsum⎥⎥⎥

⎦

⎤

⎢⎢⎢

⎣

⎡

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

minusminus⎟

⎟

⎠

⎞

⎜⎜

⎝

⎛

minus+

⎥⎥

⎦

⎤

⎢⎢

⎣

⎡

⎟⎟⎠

⎞⎜⎜⎝

⎛

minusminus⎟

⎟⎠

⎞⎜⎜⎝

⎛

minus=

j j

CAl

j

CAlCAl

i i

CO

i

COCO rrrrrrrr

rU

612612

44)( vvvvvvvvv σσ

εσσ

ε

a carbon atom and oxygen atoms in sapphire

a carbon atom and oxygen atoms in sapphire

a carbon atom and Al atoms in sapphire

a carbon atom and Al atoms in sapphire

Interaction between

Interaction between

C-plane C-plane a-plane a-plane

Potential wellPotential wellZhou Zhou et alet al JPCC JPCC 112 15929 (200(20088))

Synthesis of Nanotubes with Controlled Orientations and Positions

Synthesis of Nanotubes with Controlled Orientations and Positions

Catalyst

Photo Resist

QuartzSapphire

Catalyst Island

Aligned NanotubesMetal Electrode

SD

G

Dielectric Layer

3-10 nanotubes microm

Aligned Nanotubes on Quartz Using Patterned CatalystAligned Nanotubes on Quartz Using Patterned Catalystcatalyst

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

(a)

Poly Si Gate

Gate Oxide

SourceDrain Electrode

(b)

NanotubeGate Dielectric

Gate

SourceDrain Electrode

Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)

Comparison between SiliconComparison between Silicon--onon--insulator (SOI) and insulator (SOI) and NanotubeNanotube--onon--Insulator (NOI)Insulator (NOI)

SOISOISOI NOINOINOI

Common Features1 Active material (Si or SWNT) is all over the surface2 Many devices can be patterned anywhere on the substrate3 Unwanted silicon or SWNTs can be removed via etching4 SOI and NOI offer minimized parasitic capacitance faster switching speed

and lower dynamic power consumption

Common FeaturesCommon Features11 Active material (Si or SWNT) is all over the surfaceActive material (Si or SWNT) is all over the surface22 Many devices can be patterned anywhere on the substrateMany devices can be patterned anywhere on the substrate33 Unwanted silicon or Unwanted silicon or SWNTsSWNTs can be removed via etchingcan be removed via etching44 SOI and NOI offer minimized parasitic capacitance faster switchSOI and NOI offer minimized parasitic capacitance faster switching speed ing speed

and lower dynamic power consumptionand lower dynamic power consumption Zhou et al Nano Letters (2006)

a-Sapphire

Wafer-Scale Aligned Nanotube SynthesisWafer-Scale Aligned Nanotube Synthesis

1200

1000

800

600

400

200

Tem

pera

ture

200150100500

Time (min)

Growth Annealing

Key meticulous temperature control amp uniform growth

1μm

Quartz 1000

800

600

400

200Tem

pera

ture

6004002000

Time (min)

Growth Annealing

1μm

4 inch substrate

Gas in

Gas out

Quartz or Sapphire with patterned

catalyst

9 feet-long growth furnace with three-zone

Wafer-Scale CNT TransferWafer-Scale CNT TransferTransfer fullTransfer full--wafer of wafer of CNTsCNTs from quartz growth substrate to SiOfrom quartz growth substrate to SiO22Si fabrication Si fabrication

substrate substrate allows largeallows large--scale integrationscale integration

Nano Lett 9 189ndash197 20094

Wafer-Scale Aligned Nanotube Device FabricationWafer-Scale Aligned Nanotube Device Fabrication

Back-Gated Submicron TransistorsBack-Gated Submicron Transistors

Back-gated transistors

1 microm

L = 1 microm

1 microm

L = 075 microm

1 microm

L = 05 microm

I-Vg curves Channel length dependence

-120

-100

-80

-60

-40

-20

0

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

-60

-40

-20

0

I ds (μ

Α)

-1500Vds (V)

-1 V

-08 V

-06 V

-04 V

-02 V

Vg from -8V to 8V

15

10

05

I ds (m

A)

-10 -5 0 5 10Vg (V)

L = 05 microm L = 075 microm L = 1 microm L = 2 microm L = 5 microm L = 10 microm L = 20 microm

80

60

40

20

gm

(μ S

)

5 6 7 81

2 3 4 5 6 7 810

2

L(μm)

2

4

6810-6

2

4

6810-5

I DW

(mA

microm

) gm

Ion Ioff

Top-gated transistors

075 μmG

S

D

Al2O3

15

10

5

0

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

10-8

10-7

10-6

10-5

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

15

10

5

0

-5

-10

-15

I ds (μ

Α)

-10 -05 00 05 10Vds (V)

I-Vg curves I-Vds curves

Top-Gated Submicron TransistorsTop-Gated Submicron Transistors

N-type nanotube transistorsN-type nanotube transistorsHydrazine(NHydrazine(N22HH44) doping) doping

12

10

08

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds =01 V Vds =03 V Vds =05 V Vds =07 V Vds =09 V Vds =11 V

Before

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds=01 VVds=03 VVds=05VVds=07 VVds=09 VVds=11 V

After

Gain asymp54

10

08

06

04

02

00

Vou

t (V)

50454035302520

Vin (V)

6

5

4

3

2

1

0

I (nA)

Vout

I

Inverter

Gain =54

K doping

10

8

6

4

2

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

Before K doping After K doping

Gain asymp 5

p-type

n-type

15

10

05

00V

out (

V)

252015100500

Vin (V)

Gain=5

Potassium Doping and CMOS InverterPotassium Doping and CMOS Inverter

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

CMOS NAND amp NORCMOS NAND amp NORIndividual back-gated

NOR NAND

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

10 μm 10 μm10 μm

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Infrastructure Nanotube CVD Generation IInfrastructure Nanotube CVD Generation I

1 μm

1 μm

26 nm in diameter

10 nm in diameter

High-quality nanotubes can be grown at specific positions

-60

-50

-40

-30

-20

-10

0

I DS(

nA)

-10-08-06-04-0200VDS(V)

Vg -4 V

0 V

2 V

6 V

Nanotube transistor can be easily produced

Si back gate

SiO2

S D

Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter

Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter

Carbon Nanotube Field-Effect Inverters X Liu R Lee J Han C Zhou Appl Phys Lett 79 3329 (2001)

One of the first integrated systems made of carbon nanotubes

Si back gate

K

Vin

Vout

VDD GND

p-type CNT n-type CNT

60

40

20

0

I DS(

nA)

-4 -2 0 2 4Vg(V)

VDS=10 mV

P type MOSFET12

8

4

0

I DS (

nA)

-4 -2 0 2 4Vg (V)

VDS=10 mV

N type MOSFET25

20

15

10

05

00

Vou

t(V)

252015100500Vin(V)

VDD=29 V

Vin Vout

0 V

VDD

p

n

Integrated Nanotube SystemsRing Oscillators Demonstrated by Avouris et al

Integrated Nanotube SystemsRing Oscillators Demonstrated by Avouris et al

Ph Avouris et al Science 311 1735 (2006)

Is there a way to assemble large quantities of nanotube devices

State-of-the-art of nanotube integration

Aligned Nanotubes for Devices and Circuits Aligned Nanotubes for Devices and Circuits

-- Project Mission Project Mission We want to tackle the challenging issue of We want to tackle the challenging issue of nanotube nanotube assembly and integrationassembly and integration

We want to grow carbon nanotubes withWe want to grow carbon nanotubes withControlled orientation (achieved by using Controlled orientation (achieved by using sapphire and quartz) sapphire and quartz) Controlled position (achieved) Controlled position (achieved) Controlled density (achieved) Controlled density (achieved) Controlled diameter (ongoing)Controlled diameter (ongoing)Controlled Controlled chiralitychirality (ongoing)(ongoing)

-- Our Approach Our Approach A novel nanotubeA novel nanotube--onon--insulator (NOI) insulator (NOI) approach based on approach based on aligned nanotubesaligned nanotubes for for integrated nanotube circuitsintegrated nanotube circuits Nanotube

devicesNanotube

circuits

Quartz SubstrateCatalyst Particle

Quartz Substrate

Nanotube

One of the first to grow aligned nanotubes on sapphireOne of the first to grow aligned nanotubes on sapphireJ of Am Chem Soc 127 5294 J of Am Chem Soc 127 5294 -- 5295 (2005) 5295 (2005)

The first to make aligned nanotube transistorsThe first to make aligned nanotube transistorsNano Letters 6 34Nano Letters 6 34--39 (2006)39 (2006)Reported by Reported by Scientific AmericanScientific American (April 2006 P16) (April 2006 P16)

The first to demonstrate waferThe first to demonstrate wafer--scale processing of aligned scale processing of aligned nanotube devices and circuitsnanotube devices and circuits

Logic circuits (CMOS inverter NAND NOR)Logic circuits (CMOS inverter NAND NOR)

The first to make transparent nanotube devicesThe first to make transparent nanotube devicesACS Nano in press (2008)ACS Nano in press (2008)

Chip

1

2

3

4

5

Our Achievements on Aligned Single-Walled NanotubesOur Achievements on Aligned SingleOur Achievements on Aligned Single--Walled NanotubesWalled Nanotubes

Synthesis of Aligned Nanotubes on Sapphire QuartzSynthesis of Aligned Nanotubes on Sapphire Quartz

Gas in

Gas out

Sapphire with catalyst

Substrate Sapphire quartzCatalyst FerritinTemperature 900degCGas flow rate

CH4 2000 sccmC2H4 10 sccmH2 800 sccm

Generation IIFull Wafer Production

Generation IIFull Wafer Production

50 μm

2 0

1 5

1 0

5N

umbe

r

2 01 0D iam e te r (nm)500 nm

134 plusmn 030 nm

1 All nanotubes grow normal to the c axis on a-plane sapphire2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin11 All nanotubes grow normal to the c axis on aAll nanotubes grow normal to the c axis on a--plane sapphireplane sapphire2 Narrow diameter distribution of 2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin

c axis

Aligned Nanotubes Grown on a-Plane SapphireAligned Nanotubes Grown on a-Plane Sapphire

Zhou et al JACS 127 5294 (2005)

Zhou Zhou et alet al Nano Letters Nano Letters (2006)(2006)(Top ten hot articles in 2006)

High density SWNTsUp to 40 nanotubes μmInter-nanotube spacing ~ 25 nm

Low density SWNTs

Control of Nanotube DensityControl of Nanotube Density

Zhou et al JACS 127 5294 (2005) Zhou Zhou et alet al Nano Letters (2006) Nano Letters (2006)

a-plane

Red spheres oxygen atomsBlue spheres aluminum atomsPurple plane a-plane orientation

Hypothetic Schematic Diagram of SWNT on a-Plane SapphireHypothetic Schematic Diagram of SWNT on a-Plane Sapphire

Calculation of Lennard-Jones Potential Calculation of Lennard-Jones Potential

sumsum⎥⎥⎥

⎦

⎤

⎢⎢⎢

⎣

⎡

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

minusminus⎟

⎟

⎠

⎞

⎜⎜

⎝

⎛

minus+

⎥⎥

⎦

⎤

⎢⎢

⎣

⎡

⎟⎟⎠

⎞⎜⎜⎝

⎛

minusminus⎟

⎟⎠

⎞⎜⎜⎝

⎛

minus=

j j

CAl

j

CAlCAl

i i

CO

i

COCO rrrrrrrr

rU

612612

44)( vvvvvvvvv σσ

εσσ

ε

a carbon atom and oxygen atoms in sapphire

a carbon atom and oxygen atoms in sapphire

a carbon atom and Al atoms in sapphire

a carbon atom and Al atoms in sapphire

Interaction between

Interaction between

C-plane C-plane a-plane a-plane

Potential wellPotential wellZhou Zhou et alet al JPCC JPCC 112 15929 (200(20088))

Synthesis of Nanotubes with Controlled Orientations and Positions

Synthesis of Nanotubes with Controlled Orientations and Positions

Catalyst

Photo Resist

QuartzSapphire

Catalyst Island

Aligned NanotubesMetal Electrode

SD

G

Dielectric Layer

3-10 nanotubes microm

Aligned Nanotubes on Quartz Using Patterned CatalystAligned Nanotubes on Quartz Using Patterned Catalystcatalyst

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

(a)

Poly Si Gate

Gate Oxide

SourceDrain Electrode

(b)

NanotubeGate Dielectric

Gate

SourceDrain Electrode

Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)

Comparison between SiliconComparison between Silicon--onon--insulator (SOI) and insulator (SOI) and NanotubeNanotube--onon--Insulator (NOI)Insulator (NOI)

SOISOISOI NOINOINOI

Common Features1 Active material (Si or SWNT) is all over the surface2 Many devices can be patterned anywhere on the substrate3 Unwanted silicon or SWNTs can be removed via etching4 SOI and NOI offer minimized parasitic capacitance faster switching speed

and lower dynamic power consumption

Common FeaturesCommon Features11 Active material (Si or SWNT) is all over the surfaceActive material (Si or SWNT) is all over the surface22 Many devices can be patterned anywhere on the substrateMany devices can be patterned anywhere on the substrate33 Unwanted silicon or Unwanted silicon or SWNTsSWNTs can be removed via etchingcan be removed via etching44 SOI and NOI offer minimized parasitic capacitance faster switchSOI and NOI offer minimized parasitic capacitance faster switching speed ing speed

and lower dynamic power consumptionand lower dynamic power consumption Zhou et al Nano Letters (2006)

a-Sapphire

Wafer-Scale Aligned Nanotube SynthesisWafer-Scale Aligned Nanotube Synthesis

1200

1000

800

600

400

200

Tem

pera

ture

200150100500

Time (min)

Growth Annealing

Key meticulous temperature control amp uniform growth

1μm

Quartz 1000

800

600

400

200Tem

pera

ture

6004002000

Time (min)

Growth Annealing

1μm

4 inch substrate

Gas in

Gas out

Quartz or Sapphire with patterned

catalyst

9 feet-long growth furnace with three-zone

Wafer-Scale CNT TransferWafer-Scale CNT TransferTransfer fullTransfer full--wafer of wafer of CNTsCNTs from quartz growth substrate to SiOfrom quartz growth substrate to SiO22Si fabrication Si fabrication

substrate substrate allows largeallows large--scale integrationscale integration

Nano Lett 9 189ndash197 20094

Wafer-Scale Aligned Nanotube Device FabricationWafer-Scale Aligned Nanotube Device Fabrication

Back-Gated Submicron TransistorsBack-Gated Submicron Transistors

Back-gated transistors

1 microm

L = 1 microm

1 microm

L = 075 microm

1 microm

L = 05 microm

I-Vg curves Channel length dependence

-120

-100

-80

-60

-40

-20

0

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

-60

-40

-20

0

I ds (μ

Α)

-1500Vds (V)

-1 V

-08 V

-06 V

-04 V

-02 V

Vg from -8V to 8V

15

10

05

I ds (m

A)

-10 -5 0 5 10Vg (V)

L = 05 microm L = 075 microm L = 1 microm L = 2 microm L = 5 microm L = 10 microm L = 20 microm

80

60

40

20

gm

(μ S

)

5 6 7 81

2 3 4 5 6 7 810

2

L(μm)

2

4

6810-6

2

4

6810-5

I DW

(mA

microm

) gm

Ion Ioff

Top-gated transistors

075 μmG

S

D

Al2O3

15

10

5

0

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

10-8

10-7

10-6

10-5

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

15

10

5

0

-5

-10

-15

I ds (μ

Α)

-10 -05 00 05 10Vds (V)

I-Vg curves I-Vds curves

Top-Gated Submicron TransistorsTop-Gated Submicron Transistors

N-type nanotube transistorsN-type nanotube transistorsHydrazine(NHydrazine(N22HH44) doping) doping

12

10

08

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds =01 V Vds =03 V Vds =05 V Vds =07 V Vds =09 V Vds =11 V

Before

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds=01 VVds=03 VVds=05VVds=07 VVds=09 VVds=11 V

After

Gain asymp54

10

08

06

04

02

00

Vou

t (V)

50454035302520

Vin (V)

6

5

4

3

2

1

0

I (nA)

Vout

I

Inverter

Gain =54

K doping

10

8

6

4

2

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

Before K doping After K doping

Gain asymp 5

p-type

n-type

15

10

05

00V

out (

V)

252015100500

Vin (V)

Gain=5

Potassium Doping and CMOS InverterPotassium Doping and CMOS Inverter

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

CMOS NAND amp NORCMOS NAND amp NORIndividual back-gated

NOR NAND

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

10 μm 10 μm10 μm

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter

Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter

Carbon Nanotube Field-Effect Inverters X Liu R Lee J Han C Zhou Appl Phys Lett 79 3329 (2001)

One of the first integrated systems made of carbon nanotubes

Si back gate

K

Vin

Vout

VDD GND

p-type CNT n-type CNT

60

40

20

0

I DS(

nA)

-4 -2 0 2 4Vg(V)

VDS=10 mV

P type MOSFET12

8

4

0

I DS (

nA)

-4 -2 0 2 4Vg (V)

VDS=10 mV

N type MOSFET25

20

15

10

05

00

Vou

t(V)

252015100500Vin(V)

VDD=29 V

Vin Vout

0 V

VDD

p

n

Integrated Nanotube SystemsRing Oscillators Demonstrated by Avouris et al

Integrated Nanotube SystemsRing Oscillators Demonstrated by Avouris et al

Ph Avouris et al Science 311 1735 (2006)

Is there a way to assemble large quantities of nanotube devices

State-of-the-art of nanotube integration

Aligned Nanotubes for Devices and Circuits Aligned Nanotubes for Devices and Circuits

-- Project Mission Project Mission We want to tackle the challenging issue of We want to tackle the challenging issue of nanotube nanotube assembly and integrationassembly and integration

We want to grow carbon nanotubes withWe want to grow carbon nanotubes withControlled orientation (achieved by using Controlled orientation (achieved by using sapphire and quartz) sapphire and quartz) Controlled position (achieved) Controlled position (achieved) Controlled density (achieved) Controlled density (achieved) Controlled diameter (ongoing)Controlled diameter (ongoing)Controlled Controlled chiralitychirality (ongoing)(ongoing)

-- Our Approach Our Approach A novel nanotubeA novel nanotube--onon--insulator (NOI) insulator (NOI) approach based on approach based on aligned nanotubesaligned nanotubes for for integrated nanotube circuitsintegrated nanotube circuits Nanotube

devicesNanotube

circuits

Quartz SubstrateCatalyst Particle

Quartz Substrate

Nanotube

One of the first to grow aligned nanotubes on sapphireOne of the first to grow aligned nanotubes on sapphireJ of Am Chem Soc 127 5294 J of Am Chem Soc 127 5294 -- 5295 (2005) 5295 (2005)

The first to make aligned nanotube transistorsThe first to make aligned nanotube transistorsNano Letters 6 34Nano Letters 6 34--39 (2006)39 (2006)Reported by Reported by Scientific AmericanScientific American (April 2006 P16) (April 2006 P16)

The first to demonstrate waferThe first to demonstrate wafer--scale processing of aligned scale processing of aligned nanotube devices and circuitsnanotube devices and circuits

Logic circuits (CMOS inverter NAND NOR)Logic circuits (CMOS inverter NAND NOR)

The first to make transparent nanotube devicesThe first to make transparent nanotube devicesACS Nano in press (2008)ACS Nano in press (2008)

Chip

1

2

3

4

5

Our Achievements on Aligned Single-Walled NanotubesOur Achievements on Aligned SingleOur Achievements on Aligned Single--Walled NanotubesWalled Nanotubes

Synthesis of Aligned Nanotubes on Sapphire QuartzSynthesis of Aligned Nanotubes on Sapphire Quartz

Gas in

Gas out

Sapphire with catalyst

Substrate Sapphire quartzCatalyst FerritinTemperature 900degCGas flow rate

CH4 2000 sccmC2H4 10 sccmH2 800 sccm

Generation IIFull Wafer Production

Generation IIFull Wafer Production

50 μm

2 0

1 5

1 0

5N

umbe

r

2 01 0D iam e te r (nm)500 nm

134 plusmn 030 nm

1 All nanotubes grow normal to the c axis on a-plane sapphire2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin11 All nanotubes grow normal to the c axis on aAll nanotubes grow normal to the c axis on a--plane sapphireplane sapphire2 Narrow diameter distribution of 2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin

c axis

Aligned Nanotubes Grown on a-Plane SapphireAligned Nanotubes Grown on a-Plane Sapphire

Zhou et al JACS 127 5294 (2005)

Zhou Zhou et alet al Nano Letters Nano Letters (2006)(2006)(Top ten hot articles in 2006)

High density SWNTsUp to 40 nanotubes μmInter-nanotube spacing ~ 25 nm

Low density SWNTs

Control of Nanotube DensityControl of Nanotube Density

Zhou et al JACS 127 5294 (2005) Zhou Zhou et alet al Nano Letters (2006) Nano Letters (2006)

a-plane

Red spheres oxygen atomsBlue spheres aluminum atomsPurple plane a-plane orientation

Hypothetic Schematic Diagram of SWNT on a-Plane SapphireHypothetic Schematic Diagram of SWNT on a-Plane Sapphire

Calculation of Lennard-Jones Potential Calculation of Lennard-Jones Potential

sumsum⎥⎥⎥

⎦

⎤

⎢⎢⎢

⎣

⎡

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

minusminus⎟

⎟

⎠

⎞

⎜⎜

⎝

⎛

minus+

⎥⎥

⎦

⎤

⎢⎢

⎣

⎡

⎟⎟⎠

⎞⎜⎜⎝

⎛

minusminus⎟

⎟⎠

⎞⎜⎜⎝

⎛

minus=

j j

CAl

j

CAlCAl

i i

CO

i

COCO rrrrrrrr

rU

612612

44)( vvvvvvvvv σσ

εσσ

ε

a carbon atom and oxygen atoms in sapphire

a carbon atom and oxygen atoms in sapphire

a carbon atom and Al atoms in sapphire

a carbon atom and Al atoms in sapphire

Interaction between

Interaction between

C-plane C-plane a-plane a-plane

Potential wellPotential wellZhou Zhou et alet al JPCC JPCC 112 15929 (200(20088))

Synthesis of Nanotubes with Controlled Orientations and Positions

Synthesis of Nanotubes with Controlled Orientations and Positions

Catalyst

Photo Resist

QuartzSapphire

Catalyst Island

Aligned NanotubesMetal Electrode

SD

G

Dielectric Layer

3-10 nanotubes microm

Aligned Nanotubes on Quartz Using Patterned CatalystAligned Nanotubes on Quartz Using Patterned Catalystcatalyst

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

(a)

Poly Si Gate

Gate Oxide

SourceDrain Electrode

(b)

NanotubeGate Dielectric

Gate

SourceDrain Electrode

Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)

Comparison between SiliconComparison between Silicon--onon--insulator (SOI) and insulator (SOI) and NanotubeNanotube--onon--Insulator (NOI)Insulator (NOI)

SOISOISOI NOINOINOI

Common Features1 Active material (Si or SWNT) is all over the surface2 Many devices can be patterned anywhere on the substrate3 Unwanted silicon or SWNTs can be removed via etching4 SOI and NOI offer minimized parasitic capacitance faster switching speed

and lower dynamic power consumption

Common FeaturesCommon Features11 Active material (Si or SWNT) is all over the surfaceActive material (Si or SWNT) is all over the surface22 Many devices can be patterned anywhere on the substrateMany devices can be patterned anywhere on the substrate33 Unwanted silicon or Unwanted silicon or SWNTsSWNTs can be removed via etchingcan be removed via etching44 SOI and NOI offer minimized parasitic capacitance faster switchSOI and NOI offer minimized parasitic capacitance faster switching speed ing speed

and lower dynamic power consumptionand lower dynamic power consumption Zhou et al Nano Letters (2006)

a-Sapphire

Wafer-Scale Aligned Nanotube SynthesisWafer-Scale Aligned Nanotube Synthesis

1200

1000

800

600

400

200

Tem

pera

ture

200150100500

Time (min)

Growth Annealing

Key meticulous temperature control amp uniform growth

1μm

Quartz 1000

800

600

400

200Tem

pera

ture

6004002000

Time (min)

Growth Annealing

1μm

4 inch substrate

Gas in

Gas out

Quartz or Sapphire with patterned

catalyst

9 feet-long growth furnace with three-zone

Wafer-Scale CNT TransferWafer-Scale CNT TransferTransfer fullTransfer full--wafer of wafer of CNTsCNTs from quartz growth substrate to SiOfrom quartz growth substrate to SiO22Si fabrication Si fabrication

substrate substrate allows largeallows large--scale integrationscale integration

Nano Lett 9 189ndash197 20094

Wafer-Scale Aligned Nanotube Device FabricationWafer-Scale Aligned Nanotube Device Fabrication

Back-Gated Submicron TransistorsBack-Gated Submicron Transistors

Back-gated transistors

1 microm

L = 1 microm

1 microm

L = 075 microm

1 microm

L = 05 microm

I-Vg curves Channel length dependence

-120

-100

-80

-60

-40

-20

0

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

-60

-40

-20

0

I ds (μ

Α)

-1500Vds (V)

-1 V

-08 V

-06 V

-04 V

-02 V

Vg from -8V to 8V

15

10

05

I ds (m

A)

-10 -5 0 5 10Vg (V)

L = 05 microm L = 075 microm L = 1 microm L = 2 microm L = 5 microm L = 10 microm L = 20 microm

80

60

40

20

gm

(μ S

)

5 6 7 81

2 3 4 5 6 7 810

2

L(μm)

2

4

6810-6

2

4

6810-5

I DW

(mA

microm

) gm

Ion Ioff

Top-gated transistors

075 μmG

S

D

Al2O3

15

10

5

0

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

10-8

10-7

10-6

10-5

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

15

10

5

0

-5

-10

-15

I ds (μ

Α)

-10 -05 00 05 10Vds (V)

I-Vg curves I-Vds curves

Top-Gated Submicron TransistorsTop-Gated Submicron Transistors

N-type nanotube transistorsN-type nanotube transistorsHydrazine(NHydrazine(N22HH44) doping) doping

12

10

08

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds =01 V Vds =03 V Vds =05 V Vds =07 V Vds =09 V Vds =11 V

Before

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds=01 VVds=03 VVds=05VVds=07 VVds=09 VVds=11 V

After

Gain asymp54

10

08

06

04

02

00

Vou

t (V)

50454035302520

Vin (V)

6

5

4

3

2

1

0

I (nA)

Vout

I

Inverter

Gain =54

K doping

10

8

6

4

2

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

Before K doping After K doping

Gain asymp 5

p-type

n-type

15

10

05

00V

out (

V)

252015100500

Vin (V)

Gain=5

Potassium Doping and CMOS InverterPotassium Doping and CMOS Inverter

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

CMOS NAND amp NORCMOS NAND amp NORIndividual back-gated

NOR NAND

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

10 μm 10 μm10 μm

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Integrated Nanotube SystemsRing Oscillators Demonstrated by Avouris et al

Integrated Nanotube SystemsRing Oscillators Demonstrated by Avouris et al

Ph Avouris et al Science 311 1735 (2006)

Is there a way to assemble large quantities of nanotube devices

State-of-the-art of nanotube integration

Aligned Nanotubes for Devices and Circuits Aligned Nanotubes for Devices and Circuits

-- Project Mission Project Mission We want to tackle the challenging issue of We want to tackle the challenging issue of nanotube nanotube assembly and integrationassembly and integration

We want to grow carbon nanotubes withWe want to grow carbon nanotubes withControlled orientation (achieved by using Controlled orientation (achieved by using sapphire and quartz) sapphire and quartz) Controlled position (achieved) Controlled position (achieved) Controlled density (achieved) Controlled density (achieved) Controlled diameter (ongoing)Controlled diameter (ongoing)Controlled Controlled chiralitychirality (ongoing)(ongoing)

-- Our Approach Our Approach A novel nanotubeA novel nanotube--onon--insulator (NOI) insulator (NOI) approach based on approach based on aligned nanotubesaligned nanotubes for for integrated nanotube circuitsintegrated nanotube circuits Nanotube

devicesNanotube

circuits

Quartz SubstrateCatalyst Particle

Quartz Substrate

Nanotube

One of the first to grow aligned nanotubes on sapphireOne of the first to grow aligned nanotubes on sapphireJ of Am Chem Soc 127 5294 J of Am Chem Soc 127 5294 -- 5295 (2005) 5295 (2005)

The first to make aligned nanotube transistorsThe first to make aligned nanotube transistorsNano Letters 6 34Nano Letters 6 34--39 (2006)39 (2006)Reported by Reported by Scientific AmericanScientific American (April 2006 P16) (April 2006 P16)

The first to demonstrate waferThe first to demonstrate wafer--scale processing of aligned scale processing of aligned nanotube devices and circuitsnanotube devices and circuits

Logic circuits (CMOS inverter NAND NOR)Logic circuits (CMOS inverter NAND NOR)

The first to make transparent nanotube devicesThe first to make transparent nanotube devicesACS Nano in press (2008)ACS Nano in press (2008)

Chip

1

2

3

4

5

Our Achievements on Aligned Single-Walled NanotubesOur Achievements on Aligned SingleOur Achievements on Aligned Single--Walled NanotubesWalled Nanotubes

Synthesis of Aligned Nanotubes on Sapphire QuartzSynthesis of Aligned Nanotubes on Sapphire Quartz

Gas in

Gas out

Sapphire with catalyst

Substrate Sapphire quartzCatalyst FerritinTemperature 900degCGas flow rate

CH4 2000 sccmC2H4 10 sccmH2 800 sccm

Generation IIFull Wafer Production

Generation IIFull Wafer Production

50 μm

2 0

1 5

1 0

5N

umbe

r

2 01 0D iam e te r (nm)500 nm

134 plusmn 030 nm

1 All nanotubes grow normal to the c axis on a-plane sapphire2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin11 All nanotubes grow normal to the c axis on aAll nanotubes grow normal to the c axis on a--plane sapphireplane sapphire2 Narrow diameter distribution of 2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin

c axis

Aligned Nanotubes Grown on a-Plane SapphireAligned Nanotubes Grown on a-Plane Sapphire

Zhou et al JACS 127 5294 (2005)

Zhou Zhou et alet al Nano Letters Nano Letters (2006)(2006)(Top ten hot articles in 2006)

High density SWNTsUp to 40 nanotubes μmInter-nanotube spacing ~ 25 nm

Low density SWNTs

Control of Nanotube DensityControl of Nanotube Density

Zhou et al JACS 127 5294 (2005) Zhou Zhou et alet al Nano Letters (2006) Nano Letters (2006)

a-plane

Red spheres oxygen atomsBlue spheres aluminum atomsPurple plane a-plane orientation

Hypothetic Schematic Diagram of SWNT on a-Plane SapphireHypothetic Schematic Diagram of SWNT on a-Plane Sapphire

Calculation of Lennard-Jones Potential Calculation of Lennard-Jones Potential

sumsum⎥⎥⎥

⎦

⎤

⎢⎢⎢

⎣

⎡

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

minusminus⎟

⎟

⎠

⎞

⎜⎜

⎝

⎛

minus+

⎥⎥

⎦

⎤

⎢⎢

⎣

⎡

⎟⎟⎠

⎞⎜⎜⎝

⎛

minusminus⎟

⎟⎠

⎞⎜⎜⎝

⎛

minus=

j j

CAl

j

CAlCAl

i i

CO

i

COCO rrrrrrrr

rU

612612

44)( vvvvvvvvv σσ

εσσ

ε

a carbon atom and oxygen atoms in sapphire

a carbon atom and oxygen atoms in sapphire

a carbon atom and Al atoms in sapphire

a carbon atom and Al atoms in sapphire

Interaction between

Interaction between

C-plane C-plane a-plane a-plane

Potential wellPotential wellZhou Zhou et alet al JPCC JPCC 112 15929 (200(20088))

Synthesis of Nanotubes with Controlled Orientations and Positions

Synthesis of Nanotubes with Controlled Orientations and Positions

Catalyst

Photo Resist

QuartzSapphire

Catalyst Island

Aligned NanotubesMetal Electrode

SD

G

Dielectric Layer

3-10 nanotubes microm

Aligned Nanotubes on Quartz Using Patterned CatalystAligned Nanotubes on Quartz Using Patterned Catalystcatalyst

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

(a)

Poly Si Gate

Gate Oxide

SourceDrain Electrode

(b)

NanotubeGate Dielectric

Gate

SourceDrain Electrode

Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)

Comparison between SiliconComparison between Silicon--onon--insulator (SOI) and insulator (SOI) and NanotubeNanotube--onon--Insulator (NOI)Insulator (NOI)

SOISOISOI NOINOINOI

Common Features1 Active material (Si or SWNT) is all over the surface2 Many devices can be patterned anywhere on the substrate3 Unwanted silicon or SWNTs can be removed via etching4 SOI and NOI offer minimized parasitic capacitance faster switching speed

and lower dynamic power consumption

Common FeaturesCommon Features11 Active material (Si or SWNT) is all over the surfaceActive material (Si or SWNT) is all over the surface22 Many devices can be patterned anywhere on the substrateMany devices can be patterned anywhere on the substrate33 Unwanted silicon or Unwanted silicon or SWNTsSWNTs can be removed via etchingcan be removed via etching44 SOI and NOI offer minimized parasitic capacitance faster switchSOI and NOI offer minimized parasitic capacitance faster switching speed ing speed

and lower dynamic power consumptionand lower dynamic power consumption Zhou et al Nano Letters (2006)

a-Sapphire

Wafer-Scale Aligned Nanotube SynthesisWafer-Scale Aligned Nanotube Synthesis

1200

1000

800

600

400

200

Tem

pera

ture

200150100500

Time (min)

Growth Annealing

Key meticulous temperature control amp uniform growth

1μm

Quartz 1000

800

600

400

200Tem

pera

ture

6004002000

Time (min)

Growth Annealing

1μm

4 inch substrate

Gas in

Gas out

Quartz or Sapphire with patterned

catalyst

9 feet-long growth furnace with three-zone

Wafer-Scale CNT TransferWafer-Scale CNT TransferTransfer fullTransfer full--wafer of wafer of CNTsCNTs from quartz growth substrate to SiOfrom quartz growth substrate to SiO22Si fabrication Si fabrication

substrate substrate allows largeallows large--scale integrationscale integration

Nano Lett 9 189ndash197 20094

Wafer-Scale Aligned Nanotube Device FabricationWafer-Scale Aligned Nanotube Device Fabrication

Back-Gated Submicron TransistorsBack-Gated Submicron Transistors

Back-gated transistors

1 microm

L = 1 microm

1 microm

L = 075 microm

1 microm

L = 05 microm

I-Vg curves Channel length dependence

-120

-100

-80

-60

-40

-20

0

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

-60

-40

-20

0

I ds (μ

Α)

-1500Vds (V)

-1 V

-08 V

-06 V

-04 V

-02 V

Vg from -8V to 8V

15

10

05

I ds (m

A)

-10 -5 0 5 10Vg (V)

L = 05 microm L = 075 microm L = 1 microm L = 2 microm L = 5 microm L = 10 microm L = 20 microm

80

60

40

20

gm

(μ S

)

5 6 7 81

2 3 4 5 6 7 810

2

L(μm)

2

4

6810-6

2

4

6810-5

I DW

(mA

microm

) gm

Ion Ioff

Top-gated transistors

075 μmG

S

D

Al2O3

15

10

5

0

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

10-8

10-7

10-6

10-5

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

15

10

5

0

-5

-10

-15

I ds (μ

Α)

-10 -05 00 05 10Vds (V)

I-Vg curves I-Vds curves

Top-Gated Submicron TransistorsTop-Gated Submicron Transistors

N-type nanotube transistorsN-type nanotube transistorsHydrazine(NHydrazine(N22HH44) doping) doping

12

10

08

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds =01 V Vds =03 V Vds =05 V Vds =07 V Vds =09 V Vds =11 V

Before

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds=01 VVds=03 VVds=05VVds=07 VVds=09 VVds=11 V

After

Gain asymp54

10

08

06

04

02

00

Vou

t (V)

50454035302520

Vin (V)

6

5

4

3

2

1

0

I (nA)

Vout

I

Inverter

Gain =54

K doping

10

8

6

4

2

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

Before K doping After K doping

Gain asymp 5

p-type

n-type

15

10

05

00V

out (

V)

252015100500

Vin (V)

Gain=5

Potassium Doping and CMOS InverterPotassium Doping and CMOS Inverter

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

CMOS NAND amp NORCMOS NAND amp NORIndividual back-gated

NOR NAND

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

10 μm 10 μm10 μm

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Aligned Nanotubes for Devices and Circuits Aligned Nanotubes for Devices and Circuits

-- Project Mission Project Mission We want to tackle the challenging issue of We want to tackle the challenging issue of nanotube nanotube assembly and integrationassembly and integration

We want to grow carbon nanotubes withWe want to grow carbon nanotubes withControlled orientation (achieved by using Controlled orientation (achieved by using sapphire and quartz) sapphire and quartz) Controlled position (achieved) Controlled position (achieved) Controlled density (achieved) Controlled density (achieved) Controlled diameter (ongoing)Controlled diameter (ongoing)Controlled Controlled chiralitychirality (ongoing)(ongoing)

-- Our Approach Our Approach A novel nanotubeA novel nanotube--onon--insulator (NOI) insulator (NOI) approach based on approach based on aligned nanotubesaligned nanotubes for for integrated nanotube circuitsintegrated nanotube circuits Nanotube

devicesNanotube

circuits

Quartz SubstrateCatalyst Particle

Quartz Substrate

Nanotube

One of the first to grow aligned nanotubes on sapphireOne of the first to grow aligned nanotubes on sapphireJ of Am Chem Soc 127 5294 J of Am Chem Soc 127 5294 -- 5295 (2005) 5295 (2005)

The first to make aligned nanotube transistorsThe first to make aligned nanotube transistorsNano Letters 6 34Nano Letters 6 34--39 (2006)39 (2006)Reported by Reported by Scientific AmericanScientific American (April 2006 P16) (April 2006 P16)

The first to demonstrate waferThe first to demonstrate wafer--scale processing of aligned scale processing of aligned nanotube devices and circuitsnanotube devices and circuits

Logic circuits (CMOS inverter NAND NOR)Logic circuits (CMOS inverter NAND NOR)

The first to make transparent nanotube devicesThe first to make transparent nanotube devicesACS Nano in press (2008)ACS Nano in press (2008)

Chip

1

2

3

4

5

Our Achievements on Aligned Single-Walled NanotubesOur Achievements on Aligned SingleOur Achievements on Aligned Single--Walled NanotubesWalled Nanotubes

Synthesis of Aligned Nanotubes on Sapphire QuartzSynthesis of Aligned Nanotubes on Sapphire Quartz

Gas in

Gas out

Sapphire with catalyst

Substrate Sapphire quartzCatalyst FerritinTemperature 900degCGas flow rate

CH4 2000 sccmC2H4 10 sccmH2 800 sccm

Generation IIFull Wafer Production

Generation IIFull Wafer Production

50 μm

2 0

1 5

1 0

5N

umbe

r

2 01 0D iam e te r (nm)500 nm

134 plusmn 030 nm

1 All nanotubes grow normal to the c axis on a-plane sapphire2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin11 All nanotubes grow normal to the c axis on aAll nanotubes grow normal to the c axis on a--plane sapphireplane sapphire2 Narrow diameter distribution of 2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin

c axis

Aligned Nanotubes Grown on a-Plane SapphireAligned Nanotubes Grown on a-Plane Sapphire

Zhou et al JACS 127 5294 (2005)

Zhou Zhou et alet al Nano Letters Nano Letters (2006)(2006)(Top ten hot articles in 2006)

High density SWNTsUp to 40 nanotubes μmInter-nanotube spacing ~ 25 nm

Low density SWNTs

Control of Nanotube DensityControl of Nanotube Density

Zhou et al JACS 127 5294 (2005) Zhou Zhou et alet al Nano Letters (2006) Nano Letters (2006)

a-plane

Red spheres oxygen atomsBlue spheres aluminum atomsPurple plane a-plane orientation

Hypothetic Schematic Diagram of SWNT on a-Plane SapphireHypothetic Schematic Diagram of SWNT on a-Plane Sapphire

Calculation of Lennard-Jones Potential Calculation of Lennard-Jones Potential

sumsum⎥⎥⎥

⎦

⎤

⎢⎢⎢

⎣

⎡

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

minusminus⎟

⎟

⎠

⎞

⎜⎜

⎝

⎛

minus+

⎥⎥

⎦

⎤

⎢⎢

⎣

⎡

⎟⎟⎠

⎞⎜⎜⎝

⎛

minusminus⎟

⎟⎠

⎞⎜⎜⎝

⎛

minus=

j j

CAl

j

CAlCAl

i i

CO

i

COCO rrrrrrrr

rU

612612

44)( vvvvvvvvv σσ

εσσ

ε

a carbon atom and oxygen atoms in sapphire

a carbon atom and oxygen atoms in sapphire

a carbon atom and Al atoms in sapphire

a carbon atom and Al atoms in sapphire

Interaction between

Interaction between

C-plane C-plane a-plane a-plane

Potential wellPotential wellZhou Zhou et alet al JPCC JPCC 112 15929 (200(20088))

Synthesis of Nanotubes with Controlled Orientations and Positions

Synthesis of Nanotubes with Controlled Orientations and Positions

Catalyst

Photo Resist

QuartzSapphire

Catalyst Island

Aligned NanotubesMetal Electrode

SD

G

Dielectric Layer

3-10 nanotubes microm

Aligned Nanotubes on Quartz Using Patterned CatalystAligned Nanotubes on Quartz Using Patterned Catalystcatalyst

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

(a)

Poly Si Gate

Gate Oxide

SourceDrain Electrode

(b)

NanotubeGate Dielectric

Gate

SourceDrain Electrode

Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)

Comparison between SiliconComparison between Silicon--onon--insulator (SOI) and insulator (SOI) and NanotubeNanotube--onon--Insulator (NOI)Insulator (NOI)

SOISOISOI NOINOINOI

Common Features1 Active material (Si or SWNT) is all over the surface2 Many devices can be patterned anywhere on the substrate3 Unwanted silicon or SWNTs can be removed via etching4 SOI and NOI offer minimized parasitic capacitance faster switching speed

and lower dynamic power consumption

Common FeaturesCommon Features11 Active material (Si or SWNT) is all over the surfaceActive material (Si or SWNT) is all over the surface22 Many devices can be patterned anywhere on the substrateMany devices can be patterned anywhere on the substrate33 Unwanted silicon or Unwanted silicon or SWNTsSWNTs can be removed via etchingcan be removed via etching44 SOI and NOI offer minimized parasitic capacitance faster switchSOI and NOI offer minimized parasitic capacitance faster switching speed ing speed

and lower dynamic power consumptionand lower dynamic power consumption Zhou et al Nano Letters (2006)

a-Sapphire

Wafer-Scale Aligned Nanotube SynthesisWafer-Scale Aligned Nanotube Synthesis

1200

1000

800

600

400

200

Tem

pera

ture

200150100500

Time (min)

Growth Annealing

Key meticulous temperature control amp uniform growth

1μm

Quartz 1000

800

600

400

200Tem

pera

ture

6004002000

Time (min)

Growth Annealing

1μm

4 inch substrate

Gas in

Gas out

Quartz or Sapphire with patterned

catalyst

9 feet-long growth furnace with three-zone

Wafer-Scale CNT TransferWafer-Scale CNT TransferTransfer fullTransfer full--wafer of wafer of CNTsCNTs from quartz growth substrate to SiOfrom quartz growth substrate to SiO22Si fabrication Si fabrication

substrate substrate allows largeallows large--scale integrationscale integration

Nano Lett 9 189ndash197 20094

Wafer-Scale Aligned Nanotube Device FabricationWafer-Scale Aligned Nanotube Device Fabrication

Back-Gated Submicron TransistorsBack-Gated Submicron Transistors

Back-gated transistors

1 microm

L = 1 microm

1 microm

L = 075 microm

1 microm

L = 05 microm

I-Vg curves Channel length dependence

-120

-100

-80

-60

-40

-20

0

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

-60

-40

-20

0

I ds (μ

Α)

-1500Vds (V)

-1 V

-08 V

-06 V

-04 V

-02 V

Vg from -8V to 8V

15

10

05

I ds (m

A)

-10 -5 0 5 10Vg (V)

L = 05 microm L = 075 microm L = 1 microm L = 2 microm L = 5 microm L = 10 microm L = 20 microm

80

60

40

20

gm

(μ S

)

5 6 7 81

2 3 4 5 6 7 810

2

L(μm)

2

4

6810-6

2

4

6810-5

I DW

(mA

microm

) gm

Ion Ioff

Top-gated transistors

075 μmG

S

D

Al2O3

15

10

5

0

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

10-8

10-7

10-6

10-5

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

15

10

5

0

-5

-10

-15

I ds (μ

Α)

-10 -05 00 05 10Vds (V)

I-Vg curves I-Vds curves

Top-Gated Submicron TransistorsTop-Gated Submicron Transistors

N-type nanotube transistorsN-type nanotube transistorsHydrazine(NHydrazine(N22HH44) doping) doping

12

10

08

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds =01 V Vds =03 V Vds =05 V Vds =07 V Vds =09 V Vds =11 V

Before

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds=01 VVds=03 VVds=05VVds=07 VVds=09 VVds=11 V

After

Gain asymp54

10

08

06

04

02

00

Vou

t (V)

50454035302520

Vin (V)

6

5

4

3

2

1

0

I (nA)

Vout

I

Inverter

Gain =54

K doping

10

8

6

4

2

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

Before K doping After K doping

Gain asymp 5

p-type

n-type

15

10

05

00V

out (

V)

252015100500

Vin (V)

Gain=5

Potassium Doping and CMOS InverterPotassium Doping and CMOS Inverter

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

CMOS NAND amp NORCMOS NAND amp NORIndividual back-gated

NOR NAND

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

10 μm 10 μm10 μm

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

One of the first to grow aligned nanotubes on sapphireOne of the first to grow aligned nanotubes on sapphireJ of Am Chem Soc 127 5294 J of Am Chem Soc 127 5294 -- 5295 (2005) 5295 (2005)

The first to make aligned nanotube transistorsThe first to make aligned nanotube transistorsNano Letters 6 34Nano Letters 6 34--39 (2006)39 (2006)Reported by Reported by Scientific AmericanScientific American (April 2006 P16) (April 2006 P16)

The first to demonstrate waferThe first to demonstrate wafer--scale processing of aligned scale processing of aligned nanotube devices and circuitsnanotube devices and circuits

Logic circuits (CMOS inverter NAND NOR)Logic circuits (CMOS inverter NAND NOR)

The first to make transparent nanotube devicesThe first to make transparent nanotube devicesACS Nano in press (2008)ACS Nano in press (2008)

Chip

1

2

3

4

5

Our Achievements on Aligned Single-Walled NanotubesOur Achievements on Aligned SingleOur Achievements on Aligned Single--Walled NanotubesWalled Nanotubes

Synthesis of Aligned Nanotubes on Sapphire QuartzSynthesis of Aligned Nanotubes on Sapphire Quartz

Gas in

Gas out

Sapphire with catalyst

Substrate Sapphire quartzCatalyst FerritinTemperature 900degCGas flow rate

CH4 2000 sccmC2H4 10 sccmH2 800 sccm

Generation IIFull Wafer Production

Generation IIFull Wafer Production

50 μm

2 0

1 5

1 0

5N

umbe

r

2 01 0D iam e te r (nm)500 nm

134 plusmn 030 nm

1 All nanotubes grow normal to the c axis on a-plane sapphire2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin11 All nanotubes grow normal to the c axis on aAll nanotubes grow normal to the c axis on a--plane sapphireplane sapphire2 Narrow diameter distribution of 2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin

c axis

Aligned Nanotubes Grown on a-Plane SapphireAligned Nanotubes Grown on a-Plane Sapphire

Zhou et al JACS 127 5294 (2005)

Zhou Zhou et alet al Nano Letters Nano Letters (2006)(2006)(Top ten hot articles in 2006)

High density SWNTsUp to 40 nanotubes μmInter-nanotube spacing ~ 25 nm

Low density SWNTs

Control of Nanotube DensityControl of Nanotube Density

Zhou et al JACS 127 5294 (2005) Zhou Zhou et alet al Nano Letters (2006) Nano Letters (2006)

a-plane

Red spheres oxygen atomsBlue spheres aluminum atomsPurple plane a-plane orientation

Hypothetic Schematic Diagram of SWNT on a-Plane SapphireHypothetic Schematic Diagram of SWNT on a-Plane Sapphire

Calculation of Lennard-Jones Potential Calculation of Lennard-Jones Potential

sumsum⎥⎥⎥

⎦

⎤

⎢⎢⎢

⎣

⎡

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

minusminus⎟

⎟

⎠

⎞

⎜⎜

⎝

⎛

minus+

⎥⎥

⎦

⎤

⎢⎢

⎣

⎡

⎟⎟⎠

⎞⎜⎜⎝

⎛

minusminus⎟

⎟⎠

⎞⎜⎜⎝

⎛

minus=

j j

CAl

j

CAlCAl

i i

CO

i

COCO rrrrrrrr

rU

612612

44)( vvvvvvvvv σσ

εσσ

ε

a carbon atom and oxygen atoms in sapphire

a carbon atom and oxygen atoms in sapphire

a carbon atom and Al atoms in sapphire

a carbon atom and Al atoms in sapphire

Interaction between

Interaction between

C-plane C-plane a-plane a-plane

Potential wellPotential wellZhou Zhou et alet al JPCC JPCC 112 15929 (200(20088))

Synthesis of Nanotubes with Controlled Orientations and Positions

Synthesis of Nanotubes with Controlled Orientations and Positions

Catalyst

Photo Resist

QuartzSapphire

Catalyst Island

Aligned NanotubesMetal Electrode

SD

G

Dielectric Layer

3-10 nanotubes microm

Aligned Nanotubes on Quartz Using Patterned CatalystAligned Nanotubes on Quartz Using Patterned Catalystcatalyst

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

(a)

Poly Si Gate

Gate Oxide

SourceDrain Electrode

(b)

NanotubeGate Dielectric

Gate

SourceDrain Electrode

Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)

Comparison between SiliconComparison between Silicon--onon--insulator (SOI) and insulator (SOI) and NanotubeNanotube--onon--Insulator (NOI)Insulator (NOI)

SOISOISOI NOINOINOI

Common Features1 Active material (Si or SWNT) is all over the surface2 Many devices can be patterned anywhere on the substrate3 Unwanted silicon or SWNTs can be removed via etching4 SOI and NOI offer minimized parasitic capacitance faster switching speed

and lower dynamic power consumption

Common FeaturesCommon Features11 Active material (Si or SWNT) is all over the surfaceActive material (Si or SWNT) is all over the surface22 Many devices can be patterned anywhere on the substrateMany devices can be patterned anywhere on the substrate33 Unwanted silicon or Unwanted silicon or SWNTsSWNTs can be removed via etchingcan be removed via etching44 SOI and NOI offer minimized parasitic capacitance faster switchSOI and NOI offer minimized parasitic capacitance faster switching speed ing speed

and lower dynamic power consumptionand lower dynamic power consumption Zhou et al Nano Letters (2006)

a-Sapphire

Wafer-Scale Aligned Nanotube SynthesisWafer-Scale Aligned Nanotube Synthesis

1200

1000

800

600

400

200

Tem

pera

ture

200150100500

Time (min)

Growth Annealing

Key meticulous temperature control amp uniform growth

1μm

Quartz 1000

800

600

400

200Tem

pera

ture

6004002000

Time (min)

Growth Annealing

1μm

4 inch substrate

Gas in

Gas out

Quartz or Sapphire with patterned

catalyst

9 feet-long growth furnace with three-zone

Wafer-Scale CNT TransferWafer-Scale CNT TransferTransfer fullTransfer full--wafer of wafer of CNTsCNTs from quartz growth substrate to SiOfrom quartz growth substrate to SiO22Si fabrication Si fabrication

substrate substrate allows largeallows large--scale integrationscale integration

Nano Lett 9 189ndash197 20094

Wafer-Scale Aligned Nanotube Device FabricationWafer-Scale Aligned Nanotube Device Fabrication

Back-Gated Submicron TransistorsBack-Gated Submicron Transistors

Back-gated transistors

1 microm

L = 1 microm

1 microm

L = 075 microm

1 microm

L = 05 microm

I-Vg curves Channel length dependence

-120

-100

-80

-60

-40

-20

0

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

-60

-40

-20

0

I ds (μ

Α)

-1500Vds (V)

-1 V

-08 V

-06 V

-04 V

-02 V

Vg from -8V to 8V

15

10

05

I ds (m

A)

-10 -5 0 5 10Vg (V)

L = 05 microm L = 075 microm L = 1 microm L = 2 microm L = 5 microm L = 10 microm L = 20 microm

80

60

40

20

gm

(μ S

)

5 6 7 81

2 3 4 5 6 7 810

2

L(μm)

2

4

6810-6

2

4

6810-5

I DW

(mA

microm

) gm

Ion Ioff

Top-gated transistors

075 μmG

S

D

Al2O3

15

10

5

0

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

10-8

10-7

10-6

10-5

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

15

10

5

0

-5

-10

-15

I ds (μ

Α)

-10 -05 00 05 10Vds (V)

I-Vg curves I-Vds curves

Top-Gated Submicron TransistorsTop-Gated Submicron Transistors

N-type nanotube transistorsN-type nanotube transistorsHydrazine(NHydrazine(N22HH44) doping) doping

12

10

08

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds =01 V Vds =03 V Vds =05 V Vds =07 V Vds =09 V Vds =11 V

Before

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds=01 VVds=03 VVds=05VVds=07 VVds=09 VVds=11 V

After

Gain asymp54

10

08

06

04

02

00

Vou

t (V)

50454035302520

Vin (V)

6

5

4

3

2

1

0

I (nA)

Vout

I

Inverter

Gain =54

K doping

10

8

6

4

2

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

Before K doping After K doping

Gain asymp 5

p-type

n-type

15

10

05

00V

out (

V)

252015100500

Vin (V)

Gain=5

Potassium Doping and CMOS InverterPotassium Doping and CMOS Inverter

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

CMOS NAND amp NORCMOS NAND amp NORIndividual back-gated

NOR NAND

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

10 μm 10 μm10 μm

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Synthesis of Aligned Nanotubes on Sapphire QuartzSynthesis of Aligned Nanotubes on Sapphire Quartz

Gas in

Gas out

Sapphire with catalyst

Substrate Sapphire quartzCatalyst FerritinTemperature 900degCGas flow rate

CH4 2000 sccmC2H4 10 sccmH2 800 sccm

Generation IIFull Wafer Production

Generation IIFull Wafer Production

50 μm

2 0

1 5

1 0

5N

umbe

r

2 01 0D iam e te r (nm)500 nm

134 plusmn 030 nm

1 All nanotubes grow normal to the c axis on a-plane sapphire2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin11 All nanotubes grow normal to the c axis on aAll nanotubes grow normal to the c axis on a--plane sapphireplane sapphire2 Narrow diameter distribution of 2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin

c axis

Aligned Nanotubes Grown on a-Plane SapphireAligned Nanotubes Grown on a-Plane Sapphire

Zhou et al JACS 127 5294 (2005)

Zhou Zhou et alet al Nano Letters Nano Letters (2006)(2006)(Top ten hot articles in 2006)

High density SWNTsUp to 40 nanotubes μmInter-nanotube spacing ~ 25 nm

Low density SWNTs

Control of Nanotube DensityControl of Nanotube Density

Zhou et al JACS 127 5294 (2005) Zhou Zhou et alet al Nano Letters (2006) Nano Letters (2006)

a-plane

Red spheres oxygen atomsBlue spheres aluminum atomsPurple plane a-plane orientation

Hypothetic Schematic Diagram of SWNT on a-Plane SapphireHypothetic Schematic Diagram of SWNT on a-Plane Sapphire

Calculation of Lennard-Jones Potential Calculation of Lennard-Jones Potential

sumsum⎥⎥⎥

⎦

⎤

⎢⎢⎢

⎣

⎡

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

minusminus⎟

⎟

⎠

⎞

⎜⎜

⎝

⎛

minus+

⎥⎥

⎦

⎤

⎢⎢

⎣

⎡

⎟⎟⎠

⎞⎜⎜⎝

⎛

minusminus⎟

⎟⎠

⎞⎜⎜⎝

⎛

minus=

j j

CAl

j

CAlCAl

i i

CO

i

COCO rrrrrrrr

rU

612612

44)( vvvvvvvvv σσ

εσσ

ε

a carbon atom and oxygen atoms in sapphire

a carbon atom and oxygen atoms in sapphire

a carbon atom and Al atoms in sapphire

a carbon atom and Al atoms in sapphire

Interaction between

Interaction between

C-plane C-plane a-plane a-plane

Potential wellPotential wellZhou Zhou et alet al JPCC JPCC 112 15929 (200(20088))

Synthesis of Nanotubes with Controlled Orientations and Positions

Synthesis of Nanotubes with Controlled Orientations and Positions

Catalyst

Photo Resist

QuartzSapphire

Catalyst Island

Aligned NanotubesMetal Electrode

SD

G

Dielectric Layer

3-10 nanotubes microm

Aligned Nanotubes on Quartz Using Patterned CatalystAligned Nanotubes on Quartz Using Patterned Catalystcatalyst

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

(a)

Poly Si Gate

Gate Oxide

SourceDrain Electrode

(b)

NanotubeGate Dielectric

Gate

SourceDrain Electrode

Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)

Comparison between SiliconComparison between Silicon--onon--insulator (SOI) and insulator (SOI) and NanotubeNanotube--onon--Insulator (NOI)Insulator (NOI)

SOISOISOI NOINOINOI

Common Features1 Active material (Si or SWNT) is all over the surface2 Many devices can be patterned anywhere on the substrate3 Unwanted silicon or SWNTs can be removed via etching4 SOI and NOI offer minimized parasitic capacitance faster switching speed

and lower dynamic power consumption

Common FeaturesCommon Features11 Active material (Si or SWNT) is all over the surfaceActive material (Si or SWNT) is all over the surface22 Many devices can be patterned anywhere on the substrateMany devices can be patterned anywhere on the substrate33 Unwanted silicon or Unwanted silicon or SWNTsSWNTs can be removed via etchingcan be removed via etching44 SOI and NOI offer minimized parasitic capacitance faster switchSOI and NOI offer minimized parasitic capacitance faster switching speed ing speed

and lower dynamic power consumptionand lower dynamic power consumption Zhou et al Nano Letters (2006)

a-Sapphire

Wafer-Scale Aligned Nanotube SynthesisWafer-Scale Aligned Nanotube Synthesis

1200

1000

800

600

400

200

Tem

pera

ture

200150100500

Time (min)

Growth Annealing

Key meticulous temperature control amp uniform growth

1μm

Quartz 1000

800

600

400

200Tem

pera

ture

6004002000

Time (min)

Growth Annealing

1μm

4 inch substrate

Gas in

Gas out

Quartz or Sapphire with patterned

catalyst

9 feet-long growth furnace with three-zone

Wafer-Scale CNT TransferWafer-Scale CNT TransferTransfer fullTransfer full--wafer of wafer of CNTsCNTs from quartz growth substrate to SiOfrom quartz growth substrate to SiO22Si fabrication Si fabrication

substrate substrate allows largeallows large--scale integrationscale integration

Nano Lett 9 189ndash197 20094

Wafer-Scale Aligned Nanotube Device FabricationWafer-Scale Aligned Nanotube Device Fabrication

Back-Gated Submicron TransistorsBack-Gated Submicron Transistors

Back-gated transistors

1 microm

L = 1 microm

1 microm

L = 075 microm

1 microm

L = 05 microm

I-Vg curves Channel length dependence

-120

-100

-80

-60

-40

-20

0

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

-60

-40

-20

0

I ds (μ

Α)

-1500Vds (V)

-1 V

-08 V

-06 V

-04 V

-02 V

Vg from -8V to 8V

15

10

05

I ds (m

A)

-10 -5 0 5 10Vg (V)

L = 05 microm L = 075 microm L = 1 microm L = 2 microm L = 5 microm L = 10 microm L = 20 microm

80

60

40

20

gm

(μ S

)

5 6 7 81

2 3 4 5 6 7 810

2

L(μm)

2

4

6810-6

2

4

6810-5

I DW

(mA

microm

) gm

Ion Ioff

Top-gated transistors

075 μmG

S

D

Al2O3

15

10

5

0

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

10-8

10-7

10-6

10-5

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

15

10

5

0

-5

-10

-15

I ds (μ

Α)

-10 -05 00 05 10Vds (V)

I-Vg curves I-Vds curves

Top-Gated Submicron TransistorsTop-Gated Submicron Transistors

N-type nanotube transistorsN-type nanotube transistorsHydrazine(NHydrazine(N22HH44) doping) doping

12

10

08

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds =01 V Vds =03 V Vds =05 V Vds =07 V Vds =09 V Vds =11 V

Before

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds=01 VVds=03 VVds=05VVds=07 VVds=09 VVds=11 V

After

Gain asymp54

10

08

06

04

02

00

Vou

t (V)

50454035302520

Vin (V)

6

5

4

3

2

1

0

I (nA)

Vout

I

Inverter

Gain =54

K doping

10

8

6

4

2

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

Before K doping After K doping

Gain asymp 5

p-type

n-type

15

10

05

00V

out (

V)

252015100500

Vin (V)

Gain=5

Potassium Doping and CMOS InverterPotassium Doping and CMOS Inverter

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

CMOS NAND amp NORCMOS NAND amp NORIndividual back-gated

NOR NAND

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

10 μm 10 μm10 μm

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

50 μm

2 0

1 5

1 0

5N

umbe

r

2 01 0D iam e te r (nm)500 nm

134 plusmn 030 nm

1 All nanotubes grow normal to the c axis on a-plane sapphire2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin11 All nanotubes grow normal to the c axis on aAll nanotubes grow normal to the c axis on a--plane sapphireplane sapphire2 Narrow diameter distribution of 2 Narrow diameter distribution of 134 plusmn 030 nm obtained with commercial ferrtin

c axis

Aligned Nanotubes Grown on a-Plane SapphireAligned Nanotubes Grown on a-Plane Sapphire

Zhou et al JACS 127 5294 (2005)

Zhou Zhou et alet al Nano Letters Nano Letters (2006)(2006)(Top ten hot articles in 2006)

High density SWNTsUp to 40 nanotubes μmInter-nanotube spacing ~ 25 nm

Low density SWNTs

Control of Nanotube DensityControl of Nanotube Density

Zhou et al JACS 127 5294 (2005) Zhou Zhou et alet al Nano Letters (2006) Nano Letters (2006)

a-plane

Red spheres oxygen atomsBlue spheres aluminum atomsPurple plane a-plane orientation

Hypothetic Schematic Diagram of SWNT on a-Plane SapphireHypothetic Schematic Diagram of SWNT on a-Plane Sapphire

Calculation of Lennard-Jones Potential Calculation of Lennard-Jones Potential

sumsum⎥⎥⎥

⎦

⎤

⎢⎢⎢

⎣

⎡

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

minusminus⎟

⎟

⎠

⎞

⎜⎜

⎝

⎛

minus+

⎥⎥

⎦

⎤

⎢⎢

⎣

⎡

⎟⎟⎠

⎞⎜⎜⎝

⎛

minusminus⎟

⎟⎠

⎞⎜⎜⎝

⎛

minus=

j j

CAl

j

CAlCAl

i i

CO

i

COCO rrrrrrrr

rU

612612

44)( vvvvvvvvv σσ

εσσ

ε

a carbon atom and oxygen atoms in sapphire

a carbon atom and oxygen atoms in sapphire

a carbon atom and Al atoms in sapphire

a carbon atom and Al atoms in sapphire

Interaction between

Interaction between

C-plane C-plane a-plane a-plane

Potential wellPotential wellZhou Zhou et alet al JPCC JPCC 112 15929 (200(20088))

Synthesis of Nanotubes with Controlled Orientations and Positions

Synthesis of Nanotubes with Controlled Orientations and Positions

Catalyst

Photo Resist

QuartzSapphire

Catalyst Island

Aligned NanotubesMetal Electrode

SD

G

Dielectric Layer

3-10 nanotubes microm

Aligned Nanotubes on Quartz Using Patterned CatalystAligned Nanotubes on Quartz Using Patterned Catalystcatalyst

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

(a)

Poly Si Gate

Gate Oxide

SourceDrain Electrode

(b)

NanotubeGate Dielectric

Gate

SourceDrain Electrode

Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)

Comparison between SiliconComparison between Silicon--onon--insulator (SOI) and insulator (SOI) and NanotubeNanotube--onon--Insulator (NOI)Insulator (NOI)

SOISOISOI NOINOINOI

Common Features1 Active material (Si or SWNT) is all over the surface2 Many devices can be patterned anywhere on the substrate3 Unwanted silicon or SWNTs can be removed via etching4 SOI and NOI offer minimized parasitic capacitance faster switching speed

and lower dynamic power consumption

Common FeaturesCommon Features11 Active material (Si or SWNT) is all over the surfaceActive material (Si or SWNT) is all over the surface22 Many devices can be patterned anywhere on the substrateMany devices can be patterned anywhere on the substrate33 Unwanted silicon or Unwanted silicon or SWNTsSWNTs can be removed via etchingcan be removed via etching44 SOI and NOI offer minimized parasitic capacitance faster switchSOI and NOI offer minimized parasitic capacitance faster switching speed ing speed

and lower dynamic power consumptionand lower dynamic power consumption Zhou et al Nano Letters (2006)

a-Sapphire

Wafer-Scale Aligned Nanotube SynthesisWafer-Scale Aligned Nanotube Synthesis

1200

1000

800

600

400

200

Tem

pera

ture

200150100500

Time (min)

Growth Annealing

Key meticulous temperature control amp uniform growth

1μm

Quartz 1000

800

600

400

200Tem

pera

ture

6004002000

Time (min)

Growth Annealing

1μm

4 inch substrate

Gas in

Gas out

Quartz or Sapphire with patterned

catalyst

9 feet-long growth furnace with three-zone

Wafer-Scale CNT TransferWafer-Scale CNT TransferTransfer fullTransfer full--wafer of wafer of CNTsCNTs from quartz growth substrate to SiOfrom quartz growth substrate to SiO22Si fabrication Si fabrication

substrate substrate allows largeallows large--scale integrationscale integration

Nano Lett 9 189ndash197 20094

Wafer-Scale Aligned Nanotube Device FabricationWafer-Scale Aligned Nanotube Device Fabrication

Back-Gated Submicron TransistorsBack-Gated Submicron Transistors

Back-gated transistors

1 microm

L = 1 microm

1 microm

L = 075 microm

1 microm

L = 05 microm

I-Vg curves Channel length dependence

-120

-100

-80

-60

-40

-20

0

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

-60

-40

-20

0

I ds (μ

Α)

-1500Vds (V)

-1 V

-08 V

-06 V

-04 V

-02 V

Vg from -8V to 8V

15

10

05

I ds (m

A)

-10 -5 0 5 10Vg (V)

L = 05 microm L = 075 microm L = 1 microm L = 2 microm L = 5 microm L = 10 microm L = 20 microm

80

60

40

20

gm

(μ S

)

5 6 7 81

2 3 4 5 6 7 810

2

L(μm)

2

4

6810-6

2

4

6810-5

I DW

(mA

microm

) gm

Ion Ioff

Top-gated transistors

075 μmG

S

D

Al2O3

15

10

5

0

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

10-8

10-7

10-6

10-5

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

15

10

5

0

-5

-10

-15

I ds (μ

Α)

-10 -05 00 05 10Vds (V)

I-Vg curves I-Vds curves

Top-Gated Submicron TransistorsTop-Gated Submicron Transistors

N-type nanotube transistorsN-type nanotube transistorsHydrazine(NHydrazine(N22HH44) doping) doping

12

10

08

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds =01 V Vds =03 V Vds =05 V Vds =07 V Vds =09 V Vds =11 V

Before

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds=01 VVds=03 VVds=05VVds=07 VVds=09 VVds=11 V

After

Gain asymp54

10

08

06

04

02

00

Vou

t (V)

50454035302520

Vin (V)

6

5

4

3

2

1

0

I (nA)

Vout

I

Inverter

Gain =54

K doping

10

8

6

4

2

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

Before K doping After K doping

Gain asymp 5

p-type

n-type

15

10

05

00V

out (

V)

252015100500

Vin (V)

Gain=5

Potassium Doping and CMOS InverterPotassium Doping and CMOS Inverter

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

CMOS NAND amp NORCMOS NAND amp NORIndividual back-gated

NOR NAND

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

10 μm 10 μm10 μm

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

High density SWNTsUp to 40 nanotubes μmInter-nanotube spacing ~ 25 nm

Low density SWNTs

Control of Nanotube DensityControl of Nanotube Density

Zhou et al JACS 127 5294 (2005) Zhou Zhou et alet al Nano Letters (2006) Nano Letters (2006)

a-plane

Red spheres oxygen atomsBlue spheres aluminum atomsPurple plane a-plane orientation

Hypothetic Schematic Diagram of SWNT on a-Plane SapphireHypothetic Schematic Diagram of SWNT on a-Plane Sapphire

Calculation of Lennard-Jones Potential Calculation of Lennard-Jones Potential

sumsum⎥⎥⎥

⎦

⎤

⎢⎢⎢

⎣

⎡

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

minusminus⎟

⎟

⎠

⎞

⎜⎜

⎝

⎛

minus+

⎥⎥

⎦

⎤

⎢⎢

⎣

⎡

⎟⎟⎠

⎞⎜⎜⎝

⎛

minusminus⎟

⎟⎠

⎞⎜⎜⎝

⎛

minus=

j j

CAl

j

CAlCAl

i i

CO

i

COCO rrrrrrrr

rU

612612

44)( vvvvvvvvv σσ

εσσ

ε

a carbon atom and oxygen atoms in sapphire

a carbon atom and oxygen atoms in sapphire

a carbon atom and Al atoms in sapphire

a carbon atom and Al atoms in sapphire

Interaction between

Interaction between

C-plane C-plane a-plane a-plane

Potential wellPotential wellZhou Zhou et alet al JPCC JPCC 112 15929 (200(20088))

Synthesis of Nanotubes with Controlled Orientations and Positions

Synthesis of Nanotubes with Controlled Orientations and Positions

Catalyst

Photo Resist

QuartzSapphire

Catalyst Island

Aligned NanotubesMetal Electrode

SD

G

Dielectric Layer

3-10 nanotubes microm

Aligned Nanotubes on Quartz Using Patterned CatalystAligned Nanotubes on Quartz Using Patterned Catalystcatalyst

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

(a)

Poly Si Gate

Gate Oxide

SourceDrain Electrode

(b)

NanotubeGate Dielectric

Gate

SourceDrain Electrode

Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)

Comparison between SiliconComparison between Silicon--onon--insulator (SOI) and insulator (SOI) and NanotubeNanotube--onon--Insulator (NOI)Insulator (NOI)

SOISOISOI NOINOINOI

Common Features1 Active material (Si or SWNT) is all over the surface2 Many devices can be patterned anywhere on the substrate3 Unwanted silicon or SWNTs can be removed via etching4 SOI and NOI offer minimized parasitic capacitance faster switching speed

and lower dynamic power consumption

Common FeaturesCommon Features11 Active material (Si or SWNT) is all over the surfaceActive material (Si or SWNT) is all over the surface22 Many devices can be patterned anywhere on the substrateMany devices can be patterned anywhere on the substrate33 Unwanted silicon or Unwanted silicon or SWNTsSWNTs can be removed via etchingcan be removed via etching44 SOI and NOI offer minimized parasitic capacitance faster switchSOI and NOI offer minimized parasitic capacitance faster switching speed ing speed

and lower dynamic power consumptionand lower dynamic power consumption Zhou et al Nano Letters (2006)

a-Sapphire

Wafer-Scale Aligned Nanotube SynthesisWafer-Scale Aligned Nanotube Synthesis

1200

1000

800

600

400

200

Tem

pera

ture

200150100500

Time (min)

Growth Annealing

Key meticulous temperature control amp uniform growth

1μm

Quartz 1000

800

600

400

200Tem

pera

ture

6004002000

Time (min)

Growth Annealing

1μm

4 inch substrate

Gas in

Gas out

Quartz or Sapphire with patterned

catalyst

9 feet-long growth furnace with three-zone

Wafer-Scale CNT TransferWafer-Scale CNT TransferTransfer fullTransfer full--wafer of wafer of CNTsCNTs from quartz growth substrate to SiOfrom quartz growth substrate to SiO22Si fabrication Si fabrication

substrate substrate allows largeallows large--scale integrationscale integration

Nano Lett 9 189ndash197 20094

Wafer-Scale Aligned Nanotube Device FabricationWafer-Scale Aligned Nanotube Device Fabrication

Back-Gated Submicron TransistorsBack-Gated Submicron Transistors

Back-gated transistors

1 microm

L = 1 microm

1 microm

L = 075 microm

1 microm

L = 05 microm

I-Vg curves Channel length dependence

-120

-100

-80

-60

-40

-20

0

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

-60

-40

-20

0

I ds (μ

Α)

-1500Vds (V)

-1 V

-08 V

-06 V

-04 V

-02 V

Vg from -8V to 8V

15

10

05

I ds (m

A)

-10 -5 0 5 10Vg (V)

L = 05 microm L = 075 microm L = 1 microm L = 2 microm L = 5 microm L = 10 microm L = 20 microm

80

60

40

20

gm

(μ S

)

5 6 7 81

2 3 4 5 6 7 810

2

L(μm)

2

4

6810-6

2

4

6810-5

I DW

(mA

microm

) gm

Ion Ioff

Top-gated transistors

075 μmG

S

D

Al2O3

15

10

5

0

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

10-8

10-7

10-6

10-5

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

15

10

5

0

-5

-10

-15

I ds (μ

Α)

-10 -05 00 05 10Vds (V)

I-Vg curves I-Vds curves

Top-Gated Submicron TransistorsTop-Gated Submicron Transistors

N-type nanotube transistorsN-type nanotube transistorsHydrazine(NHydrazine(N22HH44) doping) doping

12

10

08

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds =01 V Vds =03 V Vds =05 V Vds =07 V Vds =09 V Vds =11 V

Before

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds=01 VVds=03 VVds=05VVds=07 VVds=09 VVds=11 V

After

Gain asymp54

10

08

06

04

02

00

Vou

t (V)

50454035302520

Vin (V)

6

5

4

3

2

1

0

I (nA)

Vout

I

Inverter

Gain =54

K doping

10

8

6

4

2

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

Before K doping After K doping

Gain asymp 5

p-type

n-type

15

10

05

00V

out (

V)

252015100500

Vin (V)

Gain=5

Potassium Doping and CMOS InverterPotassium Doping and CMOS Inverter

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

CMOS NAND amp NORCMOS NAND amp NORIndividual back-gated

NOR NAND

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

10 μm 10 μm10 μm

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

a-plane

Red spheres oxygen atomsBlue spheres aluminum atomsPurple plane a-plane orientation

Hypothetic Schematic Diagram of SWNT on a-Plane SapphireHypothetic Schematic Diagram of SWNT on a-Plane Sapphire

Calculation of Lennard-Jones Potential Calculation of Lennard-Jones Potential

sumsum⎥⎥⎥

⎦

⎤

⎢⎢⎢

⎣

⎡

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

minusminus⎟

⎟

⎠

⎞

⎜⎜

⎝

⎛

minus+

⎥⎥

⎦

⎤

⎢⎢

⎣

⎡

⎟⎟⎠

⎞⎜⎜⎝

⎛

minusminus⎟

⎟⎠

⎞⎜⎜⎝

⎛

minus=

j j

CAl

j

CAlCAl

i i

CO

i

COCO rrrrrrrr

rU

612612

44)( vvvvvvvvv σσ

εσσ

ε

a carbon atom and oxygen atoms in sapphire

a carbon atom and oxygen atoms in sapphire

a carbon atom and Al atoms in sapphire

a carbon atom and Al atoms in sapphire

Interaction between

Interaction between

C-plane C-plane a-plane a-plane

Potential wellPotential wellZhou Zhou et alet al JPCC JPCC 112 15929 (200(20088))

Synthesis of Nanotubes with Controlled Orientations and Positions

Synthesis of Nanotubes with Controlled Orientations and Positions

Catalyst

Photo Resist

QuartzSapphire

Catalyst Island

Aligned NanotubesMetal Electrode

SD

G

Dielectric Layer

3-10 nanotubes microm

Aligned Nanotubes on Quartz Using Patterned CatalystAligned Nanotubes on Quartz Using Patterned Catalystcatalyst

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

(a)

Poly Si Gate

Gate Oxide

SourceDrain Electrode

(b)

NanotubeGate Dielectric

Gate

SourceDrain Electrode

Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)

Comparison between SiliconComparison between Silicon--onon--insulator (SOI) and insulator (SOI) and NanotubeNanotube--onon--Insulator (NOI)Insulator (NOI)

SOISOISOI NOINOINOI

Common Features1 Active material (Si or SWNT) is all over the surface2 Many devices can be patterned anywhere on the substrate3 Unwanted silicon or SWNTs can be removed via etching4 SOI and NOI offer minimized parasitic capacitance faster switching speed

and lower dynamic power consumption

Common FeaturesCommon Features11 Active material (Si or SWNT) is all over the surfaceActive material (Si or SWNT) is all over the surface22 Many devices can be patterned anywhere on the substrateMany devices can be patterned anywhere on the substrate33 Unwanted silicon or Unwanted silicon or SWNTsSWNTs can be removed via etchingcan be removed via etching44 SOI and NOI offer minimized parasitic capacitance faster switchSOI and NOI offer minimized parasitic capacitance faster switching speed ing speed

and lower dynamic power consumptionand lower dynamic power consumption Zhou et al Nano Letters (2006)

a-Sapphire

Wafer-Scale Aligned Nanotube SynthesisWafer-Scale Aligned Nanotube Synthesis

1200

1000

800

600

400

200

Tem

pera

ture

200150100500

Time (min)

Growth Annealing

Key meticulous temperature control amp uniform growth

1μm

Quartz 1000

800

600

400

200Tem

pera

ture

6004002000

Time (min)

Growth Annealing

1μm

4 inch substrate

Gas in

Gas out

Quartz or Sapphire with patterned

catalyst

9 feet-long growth furnace with three-zone

Wafer-Scale CNT TransferWafer-Scale CNT TransferTransfer fullTransfer full--wafer of wafer of CNTsCNTs from quartz growth substrate to SiOfrom quartz growth substrate to SiO22Si fabrication Si fabrication

substrate substrate allows largeallows large--scale integrationscale integration

Nano Lett 9 189ndash197 20094

Wafer-Scale Aligned Nanotube Device FabricationWafer-Scale Aligned Nanotube Device Fabrication

Back-Gated Submicron TransistorsBack-Gated Submicron Transistors

Back-gated transistors

1 microm

L = 1 microm

1 microm

L = 075 microm

1 microm

L = 05 microm

I-Vg curves Channel length dependence

-120

-100

-80

-60

-40

-20

0

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

-60

-40

-20

0

I ds (μ

Α)

-1500Vds (V)

-1 V

-08 V

-06 V

-04 V

-02 V

Vg from -8V to 8V

15

10

05

I ds (m

A)

-10 -5 0 5 10Vg (V)

L = 05 microm L = 075 microm L = 1 microm L = 2 microm L = 5 microm L = 10 microm L = 20 microm

80

60

40

20

gm

(μ S

)

5 6 7 81

2 3 4 5 6 7 810

2

L(μm)

2

4

6810-6

2

4

6810-5

I DW

(mA

microm

) gm

Ion Ioff

Top-gated transistors

075 μmG

S

D

Al2O3

15

10

5

0

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

10-8

10-7

10-6

10-5

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

15

10

5

0

-5

-10

-15

I ds (μ

Α)

-10 -05 00 05 10Vds (V)

I-Vg curves I-Vds curves

Top-Gated Submicron TransistorsTop-Gated Submicron Transistors

N-type nanotube transistorsN-type nanotube transistorsHydrazine(NHydrazine(N22HH44) doping) doping

12

10

08

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds =01 V Vds =03 V Vds =05 V Vds =07 V Vds =09 V Vds =11 V

Before

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds=01 VVds=03 VVds=05VVds=07 VVds=09 VVds=11 V

After

Gain asymp54

10

08

06

04

02

00

Vou

t (V)

50454035302520

Vin (V)

6

5

4

3

2

1

0

I (nA)

Vout

I

Inverter

Gain =54

K doping

10

8

6

4

2

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

Before K doping After K doping

Gain asymp 5

p-type

n-type

15

10

05

00V

out (

V)

252015100500

Vin (V)

Gain=5

Potassium Doping and CMOS InverterPotassium Doping and CMOS Inverter

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

CMOS NAND amp NORCMOS NAND amp NORIndividual back-gated

NOR NAND

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

10 μm 10 μm10 μm

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Calculation of Lennard-Jones Potential Calculation of Lennard-Jones Potential

sumsum⎥⎥⎥

⎦

⎤

⎢⎢⎢

⎣

⎡

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

minusminus⎟

⎟

⎠

⎞

⎜⎜

⎝

⎛

minus+

⎥⎥

⎦

⎤

⎢⎢

⎣

⎡

⎟⎟⎠

⎞⎜⎜⎝

⎛

minusminus⎟

⎟⎠

⎞⎜⎜⎝

⎛

minus=

j j

CAl

j

CAlCAl

i i

CO

i

COCO rrrrrrrr

rU

612612

44)( vvvvvvvvv σσ

εσσ

ε

a carbon atom and oxygen atoms in sapphire

a carbon atom and oxygen atoms in sapphire

a carbon atom and Al atoms in sapphire

a carbon atom and Al atoms in sapphire

Interaction between

Interaction between

C-plane C-plane a-plane a-plane

Potential wellPotential wellZhou Zhou et alet al JPCC JPCC 112 15929 (200(20088))

Synthesis of Nanotubes with Controlled Orientations and Positions

Synthesis of Nanotubes with Controlled Orientations and Positions

Catalyst

Photo Resist

QuartzSapphire

Catalyst Island

Aligned NanotubesMetal Electrode

SD

G

Dielectric Layer

3-10 nanotubes microm

Aligned Nanotubes on Quartz Using Patterned CatalystAligned Nanotubes on Quartz Using Patterned Catalystcatalyst

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

(a)

Poly Si Gate

Gate Oxide

SourceDrain Electrode

(b)

NanotubeGate Dielectric

Gate

SourceDrain Electrode

Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)

Comparison between SiliconComparison between Silicon--onon--insulator (SOI) and insulator (SOI) and NanotubeNanotube--onon--Insulator (NOI)Insulator (NOI)

SOISOISOI NOINOINOI

Common Features1 Active material (Si or SWNT) is all over the surface2 Many devices can be patterned anywhere on the substrate3 Unwanted silicon or SWNTs can be removed via etching4 SOI and NOI offer minimized parasitic capacitance faster switching speed

and lower dynamic power consumption

Common FeaturesCommon Features11 Active material (Si or SWNT) is all over the surfaceActive material (Si or SWNT) is all over the surface22 Many devices can be patterned anywhere on the substrateMany devices can be patterned anywhere on the substrate33 Unwanted silicon or Unwanted silicon or SWNTsSWNTs can be removed via etchingcan be removed via etching44 SOI and NOI offer minimized parasitic capacitance faster switchSOI and NOI offer minimized parasitic capacitance faster switching speed ing speed

and lower dynamic power consumptionand lower dynamic power consumption Zhou et al Nano Letters (2006)

a-Sapphire

Wafer-Scale Aligned Nanotube SynthesisWafer-Scale Aligned Nanotube Synthesis

1200

1000

800

600

400

200

Tem

pera

ture

200150100500

Time (min)

Growth Annealing

Key meticulous temperature control amp uniform growth

1μm

Quartz 1000

800

600

400

200Tem

pera

ture

6004002000

Time (min)

Growth Annealing

1μm

4 inch substrate

Gas in

Gas out

Quartz or Sapphire with patterned

catalyst

9 feet-long growth furnace with three-zone

Wafer-Scale CNT TransferWafer-Scale CNT TransferTransfer fullTransfer full--wafer of wafer of CNTsCNTs from quartz growth substrate to SiOfrom quartz growth substrate to SiO22Si fabrication Si fabrication

substrate substrate allows largeallows large--scale integrationscale integration

Nano Lett 9 189ndash197 20094

Wafer-Scale Aligned Nanotube Device FabricationWafer-Scale Aligned Nanotube Device Fabrication

Back-Gated Submicron TransistorsBack-Gated Submicron Transistors

Back-gated transistors

1 microm

L = 1 microm

1 microm

L = 075 microm

1 microm

L = 05 microm

I-Vg curves Channel length dependence

-120

-100

-80

-60

-40

-20

0

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

-60

-40

-20

0

I ds (μ

Α)

-1500Vds (V)

-1 V

-08 V

-06 V

-04 V

-02 V

Vg from -8V to 8V

15

10

05

I ds (m

A)

-10 -5 0 5 10Vg (V)

L = 05 microm L = 075 microm L = 1 microm L = 2 microm L = 5 microm L = 10 microm L = 20 microm

80

60

40

20

gm

(μ S

)

5 6 7 81

2 3 4 5 6 7 810

2

L(μm)

2

4

6810-6

2

4

6810-5

I DW

(mA

microm

) gm

Ion Ioff

Top-gated transistors

075 μmG

S

D

Al2O3

15

10

5

0

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

10-8

10-7

10-6

10-5

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

15

10

5

0

-5

-10

-15

I ds (μ

Α)

-10 -05 00 05 10Vds (V)

I-Vg curves I-Vds curves

Top-Gated Submicron TransistorsTop-Gated Submicron Transistors

N-type nanotube transistorsN-type nanotube transistorsHydrazine(NHydrazine(N22HH44) doping) doping

12

10

08

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds =01 V Vds =03 V Vds =05 V Vds =07 V Vds =09 V Vds =11 V

Before

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds=01 VVds=03 VVds=05VVds=07 VVds=09 VVds=11 V

After

Gain asymp54

10

08

06

04

02

00

Vou

t (V)

50454035302520

Vin (V)

6

5

4

3

2

1

0

I (nA)

Vout

I

Inverter

Gain =54

K doping

10

8

6

4

2

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

Before K doping After K doping

Gain asymp 5

p-type

n-type

15

10

05

00V

out (

V)

252015100500

Vin (V)

Gain=5

Potassium Doping and CMOS InverterPotassium Doping and CMOS Inverter

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

CMOS NAND amp NORCMOS NAND amp NORIndividual back-gated

NOR NAND

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

10 μm 10 μm10 μm

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Synthesis of Nanotubes with Controlled Orientations and Positions

Synthesis of Nanotubes with Controlled Orientations and Positions

Catalyst

Photo Resist

QuartzSapphire

Catalyst Island

Aligned NanotubesMetal Electrode

SD

G

Dielectric Layer

3-10 nanotubes microm

Aligned Nanotubes on Quartz Using Patterned CatalystAligned Nanotubes on Quartz Using Patterned Catalystcatalyst

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

(a)

Poly Si Gate

Gate Oxide

SourceDrain Electrode

(b)

NanotubeGate Dielectric

Gate

SourceDrain Electrode

Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)

Comparison between SiliconComparison between Silicon--onon--insulator (SOI) and insulator (SOI) and NanotubeNanotube--onon--Insulator (NOI)Insulator (NOI)

SOISOISOI NOINOINOI

Common Features1 Active material (Si or SWNT) is all over the surface2 Many devices can be patterned anywhere on the substrate3 Unwanted silicon or SWNTs can be removed via etching4 SOI and NOI offer minimized parasitic capacitance faster switching speed

and lower dynamic power consumption

Common FeaturesCommon Features11 Active material (Si or SWNT) is all over the surfaceActive material (Si or SWNT) is all over the surface22 Many devices can be patterned anywhere on the substrateMany devices can be patterned anywhere on the substrate33 Unwanted silicon or Unwanted silicon or SWNTsSWNTs can be removed via etchingcan be removed via etching44 SOI and NOI offer minimized parasitic capacitance faster switchSOI and NOI offer minimized parasitic capacitance faster switching speed ing speed

and lower dynamic power consumptionand lower dynamic power consumption Zhou et al Nano Letters (2006)

a-Sapphire

Wafer-Scale Aligned Nanotube SynthesisWafer-Scale Aligned Nanotube Synthesis

1200

1000

800

600

400

200

Tem

pera

ture

200150100500

Time (min)

Growth Annealing

Key meticulous temperature control amp uniform growth

1μm

Quartz 1000

800

600

400

200Tem

pera

ture

6004002000

Time (min)

Growth Annealing

1μm

4 inch substrate

Gas in

Gas out

Quartz or Sapphire with patterned

catalyst

9 feet-long growth furnace with three-zone

Wafer-Scale CNT TransferWafer-Scale CNT TransferTransfer fullTransfer full--wafer of wafer of CNTsCNTs from quartz growth substrate to SiOfrom quartz growth substrate to SiO22Si fabrication Si fabrication

substrate substrate allows largeallows large--scale integrationscale integration

Nano Lett 9 189ndash197 20094

Wafer-Scale Aligned Nanotube Device FabricationWafer-Scale Aligned Nanotube Device Fabrication

Back-Gated Submicron TransistorsBack-Gated Submicron Transistors

Back-gated transistors

1 microm

L = 1 microm

1 microm

L = 075 microm

1 microm

L = 05 microm

I-Vg curves Channel length dependence

-120

-100

-80

-60

-40

-20

0

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

-60

-40

-20

0

I ds (μ

Α)

-1500Vds (V)

-1 V

-08 V

-06 V

-04 V

-02 V

Vg from -8V to 8V

15

10

05

I ds (m

A)

-10 -5 0 5 10Vg (V)

L = 05 microm L = 075 microm L = 1 microm L = 2 microm L = 5 microm L = 10 microm L = 20 microm

80

60

40

20

gm

(μ S

)

5 6 7 81

2 3 4 5 6 7 810

2

L(μm)

2

4

6810-6

2

4

6810-5

I DW

(mA

microm

) gm

Ion Ioff

Top-gated transistors

075 μmG

S

D

Al2O3

15

10

5

0

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

10-8

10-7

10-6

10-5

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

15

10

5

0

-5

-10

-15

I ds (μ

Α)

-10 -05 00 05 10Vds (V)

I-Vg curves I-Vds curves

Top-Gated Submicron TransistorsTop-Gated Submicron Transistors

N-type nanotube transistorsN-type nanotube transistorsHydrazine(NHydrazine(N22HH44) doping) doping

12

10

08

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds =01 V Vds =03 V Vds =05 V Vds =07 V Vds =09 V Vds =11 V

Before

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds=01 VVds=03 VVds=05VVds=07 VVds=09 VVds=11 V

After

Gain asymp54

10

08

06

04

02

00

Vou

t (V)

50454035302520

Vin (V)

6

5

4

3

2

1

0

I (nA)

Vout

I

Inverter

Gain =54

K doping

10

8

6

4

2

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

Before K doping After K doping

Gain asymp 5

p-type

n-type

15

10

05

00V

out (

V)

252015100500

Vin (V)

Gain=5

Potassium Doping and CMOS InverterPotassium Doping and CMOS Inverter

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

CMOS NAND amp NORCMOS NAND amp NORIndividual back-gated

NOR NAND

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

10 μm 10 μm10 μm

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

3-10 nanotubes microm

Aligned Nanotubes on Quartz Using Patterned CatalystAligned Nanotubes on Quartz Using Patterned Catalystcatalyst

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

(a)

Poly Si Gate

Gate Oxide

SourceDrain Electrode

(b)

NanotubeGate Dielectric

Gate

SourceDrain Electrode

Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)

Comparison between SiliconComparison between Silicon--onon--insulator (SOI) and insulator (SOI) and NanotubeNanotube--onon--Insulator (NOI)Insulator (NOI)

SOISOISOI NOINOINOI

Common Features1 Active material (Si or SWNT) is all over the surface2 Many devices can be patterned anywhere on the substrate3 Unwanted silicon or SWNTs can be removed via etching4 SOI and NOI offer minimized parasitic capacitance faster switching speed

and lower dynamic power consumption

Common FeaturesCommon Features11 Active material (Si or SWNT) is all over the surfaceActive material (Si or SWNT) is all over the surface22 Many devices can be patterned anywhere on the substrateMany devices can be patterned anywhere on the substrate33 Unwanted silicon or Unwanted silicon or SWNTsSWNTs can be removed via etchingcan be removed via etching44 SOI and NOI offer minimized parasitic capacitance faster switchSOI and NOI offer minimized parasitic capacitance faster switching speed ing speed

and lower dynamic power consumptionand lower dynamic power consumption Zhou et al Nano Letters (2006)

a-Sapphire

Wafer-Scale Aligned Nanotube SynthesisWafer-Scale Aligned Nanotube Synthesis

1200

1000

800

600

400

200

Tem

pera

ture

200150100500

Time (min)

Growth Annealing

Key meticulous temperature control amp uniform growth

1μm

Quartz 1000

800

600

400

200Tem

pera

ture

6004002000

Time (min)

Growth Annealing

1μm

4 inch substrate

Gas in

Gas out

Quartz or Sapphire with patterned

catalyst

9 feet-long growth furnace with three-zone

Wafer-Scale CNT TransferWafer-Scale CNT TransferTransfer fullTransfer full--wafer of wafer of CNTsCNTs from quartz growth substrate to SiOfrom quartz growth substrate to SiO22Si fabrication Si fabrication

substrate substrate allows largeallows large--scale integrationscale integration

Nano Lett 9 189ndash197 20094

Wafer-Scale Aligned Nanotube Device FabricationWafer-Scale Aligned Nanotube Device Fabrication

Back-Gated Submicron TransistorsBack-Gated Submicron Transistors

Back-gated transistors

1 microm

L = 1 microm

1 microm

L = 075 microm

1 microm

L = 05 microm

I-Vg curves Channel length dependence

-120

-100

-80

-60

-40

-20

0

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

-60

-40

-20

0

I ds (μ

Α)

-1500Vds (V)

-1 V

-08 V

-06 V

-04 V

-02 V

Vg from -8V to 8V

15

10

05

I ds (m

A)

-10 -5 0 5 10Vg (V)

L = 05 microm L = 075 microm L = 1 microm L = 2 microm L = 5 microm L = 10 microm L = 20 microm

80

60

40

20

gm

(μ S

)

5 6 7 81

2 3 4 5 6 7 810

2

L(μm)

2

4

6810-6

2

4

6810-5

I DW

(mA

microm

) gm

Ion Ioff

Top-gated transistors

075 μmG

S

D

Al2O3

15

10

5

0

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

10-8

10-7

10-6

10-5

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

15

10

5

0

-5

-10

-15

I ds (μ

Α)

-10 -05 00 05 10Vds (V)

I-Vg curves I-Vds curves

Top-Gated Submicron TransistorsTop-Gated Submicron Transistors

N-type nanotube transistorsN-type nanotube transistorsHydrazine(NHydrazine(N22HH44) doping) doping

12

10

08

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds =01 V Vds =03 V Vds =05 V Vds =07 V Vds =09 V Vds =11 V

Before

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds=01 VVds=03 VVds=05VVds=07 VVds=09 VVds=11 V

After

Gain asymp54

10

08

06

04

02

00

Vou

t (V)

50454035302520

Vin (V)

6

5

4

3

2

1

0

I (nA)

Vout

I

Inverter

Gain =54

K doping

10

8

6

4

2

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

Before K doping After K doping

Gain asymp 5

p-type

n-type

15

10

05

00V

out (

V)

252015100500

Vin (V)

Gain=5

Potassium Doping and CMOS InverterPotassium Doping and CMOS Inverter

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

CMOS NAND amp NORCMOS NAND amp NORIndividual back-gated

NOR NAND

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

10 μm 10 μm10 μm

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesTraditional Nanotube SynthesisTraditional Nanotube SynthesisAligned Nanotube SynthesisAligned Nanotube SynthesisFullFull--wafer Processing of Aligned Nanotube Electronicswafer Processing of Aligned Nanotube Electronics

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

(a)

Poly Si Gate

Gate Oxide

SourceDrain Electrode

(b)

NanotubeGate Dielectric

Gate

SourceDrain Electrode

Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)

Comparison between SiliconComparison between Silicon--onon--insulator (SOI) and insulator (SOI) and NanotubeNanotube--onon--Insulator (NOI)Insulator (NOI)

SOISOISOI NOINOINOI

Common Features1 Active material (Si or SWNT) is all over the surface2 Many devices can be patterned anywhere on the substrate3 Unwanted silicon or SWNTs can be removed via etching4 SOI and NOI offer minimized parasitic capacitance faster switching speed

and lower dynamic power consumption

Common FeaturesCommon Features11 Active material (Si or SWNT) is all over the surfaceActive material (Si or SWNT) is all over the surface22 Many devices can be patterned anywhere on the substrateMany devices can be patterned anywhere on the substrate33 Unwanted silicon or Unwanted silicon or SWNTsSWNTs can be removed via etchingcan be removed via etching44 SOI and NOI offer minimized parasitic capacitance faster switchSOI and NOI offer minimized parasitic capacitance faster switching speed ing speed

and lower dynamic power consumptionand lower dynamic power consumption Zhou et al Nano Letters (2006)

a-Sapphire

Wafer-Scale Aligned Nanotube SynthesisWafer-Scale Aligned Nanotube Synthesis

1200

1000

800

600

400

200

Tem

pera

ture

200150100500

Time (min)

Growth Annealing

Key meticulous temperature control amp uniform growth

1μm

Quartz 1000

800

600

400

200Tem

pera

ture

6004002000

Time (min)

Growth Annealing

1μm

4 inch substrate

Gas in

Gas out

Quartz or Sapphire with patterned

catalyst

9 feet-long growth furnace with three-zone

Wafer-Scale CNT TransferWafer-Scale CNT TransferTransfer fullTransfer full--wafer of wafer of CNTsCNTs from quartz growth substrate to SiOfrom quartz growth substrate to SiO22Si fabrication Si fabrication

substrate substrate allows largeallows large--scale integrationscale integration

Nano Lett 9 189ndash197 20094

Wafer-Scale Aligned Nanotube Device FabricationWafer-Scale Aligned Nanotube Device Fabrication

Back-Gated Submicron TransistorsBack-Gated Submicron Transistors

Back-gated transistors

1 microm

L = 1 microm

1 microm

L = 075 microm

1 microm

L = 05 microm

I-Vg curves Channel length dependence

-120

-100

-80

-60

-40

-20

0

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

-60

-40

-20

0

I ds (μ

Α)

-1500Vds (V)

-1 V

-08 V

-06 V

-04 V

-02 V

Vg from -8V to 8V

15

10

05

I ds (m

A)

-10 -5 0 5 10Vg (V)

L = 05 microm L = 075 microm L = 1 microm L = 2 microm L = 5 microm L = 10 microm L = 20 microm

80

60

40

20

gm

(μ S

)

5 6 7 81

2 3 4 5 6 7 810

2

L(μm)

2

4

6810-6

2

4

6810-5

I DW

(mA

microm

) gm

Ion Ioff

Top-gated transistors

075 μmG

S

D

Al2O3

15

10

5

0

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

10-8

10-7

10-6

10-5

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

15

10

5

0

-5

-10

-15

I ds (μ

Α)

-10 -05 00 05 10Vds (V)

I-Vg curves I-Vds curves

Top-Gated Submicron TransistorsTop-Gated Submicron Transistors

N-type nanotube transistorsN-type nanotube transistorsHydrazine(NHydrazine(N22HH44) doping) doping

12

10

08

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds =01 V Vds =03 V Vds =05 V Vds =07 V Vds =09 V Vds =11 V

Before

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds=01 VVds=03 VVds=05VVds=07 VVds=09 VVds=11 V

After

Gain asymp54

10

08

06

04

02

00

Vou

t (V)

50454035302520

Vin (V)

6

5

4

3

2

1

0

I (nA)

Vout

I

Inverter

Gain =54

K doping

10

8

6

4

2

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

Before K doping After K doping

Gain asymp 5

p-type

n-type

15

10

05

00V

out (

V)

252015100500

Vin (V)

Gain=5

Potassium Doping and CMOS InverterPotassium Doping and CMOS Inverter

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

CMOS NAND amp NORCMOS NAND amp NORIndividual back-gated

NOR NAND

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

10 μm 10 μm10 μm

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

(a)

Poly Si Gate

Gate Oxide

SourceDrain Electrode

(b)

NanotubeGate Dielectric

Gate

SourceDrain Electrode

Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)

Comparison between SiliconComparison between Silicon--onon--insulator (SOI) and insulator (SOI) and NanotubeNanotube--onon--Insulator (NOI)Insulator (NOI)

SOISOISOI NOINOINOI

Common Features1 Active material (Si or SWNT) is all over the surface2 Many devices can be patterned anywhere on the substrate3 Unwanted silicon or SWNTs can be removed via etching4 SOI and NOI offer minimized parasitic capacitance faster switching speed

and lower dynamic power consumption

Common FeaturesCommon Features11 Active material (Si or SWNT) is all over the surfaceActive material (Si or SWNT) is all over the surface22 Many devices can be patterned anywhere on the substrateMany devices can be patterned anywhere on the substrate33 Unwanted silicon or Unwanted silicon or SWNTsSWNTs can be removed via etchingcan be removed via etching44 SOI and NOI offer minimized parasitic capacitance faster switchSOI and NOI offer minimized parasitic capacitance faster switching speed ing speed

and lower dynamic power consumptionand lower dynamic power consumption Zhou et al Nano Letters (2006)

a-Sapphire

Wafer-Scale Aligned Nanotube SynthesisWafer-Scale Aligned Nanotube Synthesis

1200

1000

800

600

400

200

Tem

pera

ture

200150100500

Time (min)

Growth Annealing

Key meticulous temperature control amp uniform growth

1μm

Quartz 1000

800

600

400

200Tem

pera

ture

6004002000

Time (min)

Growth Annealing

1μm

4 inch substrate

Gas in

Gas out

Quartz or Sapphire with patterned

catalyst

9 feet-long growth furnace with three-zone

Wafer-Scale CNT TransferWafer-Scale CNT TransferTransfer fullTransfer full--wafer of wafer of CNTsCNTs from quartz growth substrate to SiOfrom quartz growth substrate to SiO22Si fabrication Si fabrication

substrate substrate allows largeallows large--scale integrationscale integration

Nano Lett 9 189ndash197 20094

Wafer-Scale Aligned Nanotube Device FabricationWafer-Scale Aligned Nanotube Device Fabrication

Back-Gated Submicron TransistorsBack-Gated Submicron Transistors

Back-gated transistors

1 microm

L = 1 microm

1 microm

L = 075 microm

1 microm

L = 05 microm

I-Vg curves Channel length dependence

-120

-100

-80

-60

-40

-20

0

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

-60

-40

-20

0

I ds (μ

Α)

-1500Vds (V)

-1 V

-08 V

-06 V

-04 V

-02 V

Vg from -8V to 8V

15

10

05

I ds (m

A)

-10 -5 0 5 10Vg (V)

L = 05 microm L = 075 microm L = 1 microm L = 2 microm L = 5 microm L = 10 microm L = 20 microm

80

60

40

20

gm

(μ S

)

5 6 7 81

2 3 4 5 6 7 810

2

L(μm)

2

4

6810-6

2

4

6810-5

I DW

(mA

microm

) gm

Ion Ioff

Top-gated transistors

075 μmG

S

D

Al2O3

15

10

5

0

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

10-8

10-7

10-6

10-5

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

15

10

5

0

-5

-10

-15

I ds (μ

Α)

-10 -05 00 05 10Vds (V)

I-Vg curves I-Vds curves

Top-Gated Submicron TransistorsTop-Gated Submicron Transistors

N-type nanotube transistorsN-type nanotube transistorsHydrazine(NHydrazine(N22HH44) doping) doping

12

10

08

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds =01 V Vds =03 V Vds =05 V Vds =07 V Vds =09 V Vds =11 V

Before

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds=01 VVds=03 VVds=05VVds=07 VVds=09 VVds=11 V

After

Gain asymp54

10

08

06

04

02

00

Vou

t (V)

50454035302520

Vin (V)

6

5

4

3

2

1

0

I (nA)

Vout

I

Inverter

Gain =54

K doping

10

8

6

4

2

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

Before K doping After K doping

Gain asymp 5

p-type

n-type

15

10

05

00V

out (

V)

252015100500

Vin (V)

Gain=5

Potassium Doping and CMOS InverterPotassium Doping and CMOS Inverter

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

CMOS NAND amp NORCMOS NAND amp NORIndividual back-gated

NOR NAND

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

10 μm 10 μm10 μm

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

a-Sapphire

Wafer-Scale Aligned Nanotube SynthesisWafer-Scale Aligned Nanotube Synthesis

1200

1000

800

600

400

200

Tem

pera

ture

200150100500

Time (min)

Growth Annealing

Key meticulous temperature control amp uniform growth

1μm

Quartz 1000

800

600

400

200Tem

pera

ture

6004002000

Time (min)

Growth Annealing

1μm

4 inch substrate

Gas in

Gas out

Quartz or Sapphire with patterned

catalyst

9 feet-long growth furnace with three-zone

Wafer-Scale CNT TransferWafer-Scale CNT TransferTransfer fullTransfer full--wafer of wafer of CNTsCNTs from quartz growth substrate to SiOfrom quartz growth substrate to SiO22Si fabrication Si fabrication

substrate substrate allows largeallows large--scale integrationscale integration

Nano Lett 9 189ndash197 20094

Wafer-Scale Aligned Nanotube Device FabricationWafer-Scale Aligned Nanotube Device Fabrication

Back-Gated Submicron TransistorsBack-Gated Submicron Transistors

Back-gated transistors

1 microm

L = 1 microm

1 microm

L = 075 microm

1 microm

L = 05 microm

I-Vg curves Channel length dependence

-120

-100

-80

-60

-40

-20

0

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

-60

-40

-20

0

I ds (μ

Α)

-1500Vds (V)

-1 V

-08 V

-06 V

-04 V

-02 V

Vg from -8V to 8V

15

10

05

I ds (m

A)

-10 -5 0 5 10Vg (V)

L = 05 microm L = 075 microm L = 1 microm L = 2 microm L = 5 microm L = 10 microm L = 20 microm

80

60

40

20

gm

(μ S

)

5 6 7 81

2 3 4 5 6 7 810

2

L(μm)

2

4

6810-6

2

4

6810-5

I DW

(mA

microm

) gm

Ion Ioff

Top-gated transistors

075 μmG

S

D

Al2O3

15

10

5

0

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

10-8

10-7

10-6

10-5

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

15

10

5

0

-5

-10

-15

I ds (μ

Α)

-10 -05 00 05 10Vds (V)

I-Vg curves I-Vds curves

Top-Gated Submicron TransistorsTop-Gated Submicron Transistors

N-type nanotube transistorsN-type nanotube transistorsHydrazine(NHydrazine(N22HH44) doping) doping

12

10

08

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds =01 V Vds =03 V Vds =05 V Vds =07 V Vds =09 V Vds =11 V

Before

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds=01 VVds=03 VVds=05VVds=07 VVds=09 VVds=11 V

After

Gain asymp54

10

08

06

04

02

00

Vou

t (V)

50454035302520

Vin (V)

6

5

4

3

2

1

0

I (nA)

Vout

I

Inverter

Gain =54

K doping

10

8

6

4

2

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

Before K doping After K doping

Gain asymp 5

p-type

n-type

15

10

05

00V

out (

V)

252015100500

Vin (V)

Gain=5

Potassium Doping and CMOS InverterPotassium Doping and CMOS Inverter

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

CMOS NAND amp NORCMOS NAND amp NORIndividual back-gated

NOR NAND

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

10 μm 10 μm10 μm

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Wafer-Scale CNT TransferWafer-Scale CNT TransferTransfer fullTransfer full--wafer of wafer of CNTsCNTs from quartz growth substrate to SiOfrom quartz growth substrate to SiO22Si fabrication Si fabrication

substrate substrate allows largeallows large--scale integrationscale integration

Nano Lett 9 189ndash197 20094

Wafer-Scale Aligned Nanotube Device FabricationWafer-Scale Aligned Nanotube Device Fabrication

Back-Gated Submicron TransistorsBack-Gated Submicron Transistors

Back-gated transistors

1 microm

L = 1 microm

1 microm

L = 075 microm

1 microm

L = 05 microm

I-Vg curves Channel length dependence

-120

-100

-80

-60

-40

-20

0

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

-60

-40

-20

0

I ds (μ

Α)

-1500Vds (V)

-1 V

-08 V

-06 V

-04 V

-02 V

Vg from -8V to 8V

15

10

05

I ds (m

A)

-10 -5 0 5 10Vg (V)

L = 05 microm L = 075 microm L = 1 microm L = 2 microm L = 5 microm L = 10 microm L = 20 microm

80

60

40

20

gm

(μ S

)

5 6 7 81

2 3 4 5 6 7 810

2

L(μm)

2

4

6810-6

2

4

6810-5

I DW

(mA

microm

) gm

Ion Ioff

Top-gated transistors

075 μmG

S

D

Al2O3

15

10

5

0

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

10-8

10-7

10-6

10-5

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

15

10

5

0

-5

-10

-15

I ds (μ

Α)

-10 -05 00 05 10Vds (V)

I-Vg curves I-Vds curves

Top-Gated Submicron TransistorsTop-Gated Submicron Transistors

N-type nanotube transistorsN-type nanotube transistorsHydrazine(NHydrazine(N22HH44) doping) doping

12

10

08

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds =01 V Vds =03 V Vds =05 V Vds =07 V Vds =09 V Vds =11 V

Before

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds=01 VVds=03 VVds=05VVds=07 VVds=09 VVds=11 V

After

Gain asymp54

10

08

06

04

02

00

Vou

t (V)

50454035302520

Vin (V)

6

5

4

3

2

1

0

I (nA)

Vout

I

Inverter

Gain =54

K doping

10

8

6

4

2

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

Before K doping After K doping

Gain asymp 5

p-type

n-type

15

10

05

00V

out (

V)

252015100500

Vin (V)

Gain=5

Potassium Doping and CMOS InverterPotassium Doping and CMOS Inverter

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

CMOS NAND amp NORCMOS NAND amp NORIndividual back-gated

NOR NAND

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

10 μm 10 μm10 μm

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Wafer-Scale Aligned Nanotube Device FabricationWafer-Scale Aligned Nanotube Device Fabrication

Back-Gated Submicron TransistorsBack-Gated Submicron Transistors

Back-gated transistors

1 microm

L = 1 microm

1 microm

L = 075 microm

1 microm

L = 05 microm

I-Vg curves Channel length dependence

-120

-100

-80

-60

-40

-20

0

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

-60

-40

-20

0

I ds (μ

Α)

-1500Vds (V)

-1 V

-08 V

-06 V

-04 V

-02 V

Vg from -8V to 8V

15

10

05

I ds (m

A)

-10 -5 0 5 10Vg (V)

L = 05 microm L = 075 microm L = 1 microm L = 2 microm L = 5 microm L = 10 microm L = 20 microm

80

60

40

20

gm

(μ S

)

5 6 7 81

2 3 4 5 6 7 810

2

L(μm)

2

4

6810-6

2

4

6810-5

I DW

(mA

microm

) gm

Ion Ioff

Top-gated transistors

075 μmG

S

D

Al2O3

15

10

5

0

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

10-8

10-7

10-6

10-5

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

15

10

5

0

-5

-10

-15

I ds (μ

Α)

-10 -05 00 05 10Vds (V)

I-Vg curves I-Vds curves

Top-Gated Submicron TransistorsTop-Gated Submicron Transistors

N-type nanotube transistorsN-type nanotube transistorsHydrazine(NHydrazine(N22HH44) doping) doping

12

10

08

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds =01 V Vds =03 V Vds =05 V Vds =07 V Vds =09 V Vds =11 V

Before

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds=01 VVds=03 VVds=05VVds=07 VVds=09 VVds=11 V

After

Gain asymp54

10

08

06

04

02

00

Vou

t (V)

50454035302520

Vin (V)

6

5

4

3

2

1

0

I (nA)

Vout

I

Inverter

Gain =54

K doping

10

8

6

4

2

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

Before K doping After K doping

Gain asymp 5

p-type

n-type

15

10

05

00V

out (

V)

252015100500

Vin (V)

Gain=5

Potassium Doping and CMOS InverterPotassium Doping and CMOS Inverter

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

CMOS NAND amp NORCMOS NAND amp NORIndividual back-gated

NOR NAND

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

10 μm 10 μm10 μm

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Back-Gated Submicron TransistorsBack-Gated Submicron Transistors

Back-gated transistors

1 microm

L = 1 microm

1 microm

L = 075 microm

1 microm

L = 05 microm

I-Vg curves Channel length dependence

-120

-100

-80

-60

-40

-20

0

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

-60

-40

-20

0

I ds (μ

Α)

-1500Vds (V)

-1 V

-08 V

-06 V

-04 V

-02 V

Vg from -8V to 8V

15

10

05

I ds (m

A)

-10 -5 0 5 10Vg (V)

L = 05 microm L = 075 microm L = 1 microm L = 2 microm L = 5 microm L = 10 microm L = 20 microm

80

60

40

20

gm

(μ S

)

5 6 7 81

2 3 4 5 6 7 810

2

L(μm)

2

4

6810-6

2

4

6810-5

I DW

(mA

microm

) gm

Ion Ioff

Top-gated transistors

075 μmG

S

D

Al2O3

15

10

5

0

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

10-8

10-7

10-6

10-5

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

15

10

5

0

-5

-10

-15

I ds (μ

Α)

-10 -05 00 05 10Vds (V)

I-Vg curves I-Vds curves

Top-Gated Submicron TransistorsTop-Gated Submicron Transistors

N-type nanotube transistorsN-type nanotube transistorsHydrazine(NHydrazine(N22HH44) doping) doping

12

10

08

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds =01 V Vds =03 V Vds =05 V Vds =07 V Vds =09 V Vds =11 V

Before

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds=01 VVds=03 VVds=05VVds=07 VVds=09 VVds=11 V

After

Gain asymp54

10

08

06

04

02

00

Vou

t (V)

50454035302520

Vin (V)

6

5

4

3

2

1

0

I (nA)

Vout

I

Inverter

Gain =54

K doping

10

8

6

4

2

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

Before K doping After K doping

Gain asymp 5

p-type

n-type

15

10

05

00V

out (

V)

252015100500

Vin (V)

Gain=5

Potassium Doping and CMOS InverterPotassium Doping and CMOS Inverter

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

CMOS NAND amp NORCMOS NAND amp NORIndividual back-gated

NOR NAND

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

10 μm 10 μm10 μm

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Top-gated transistors

075 μmG

S

D

Al2O3

15

10

5

0

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

10-8

10-7

10-6

10-5

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

15

10

5

0

-5

-10

-15

I ds (μ

Α)

-10 -05 00 05 10Vds (V)

I-Vg curves I-Vds curves

Top-Gated Submicron TransistorsTop-Gated Submicron Transistors

N-type nanotube transistorsN-type nanotube transistorsHydrazine(NHydrazine(N22HH44) doping) doping

12

10

08

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds =01 V Vds =03 V Vds =05 V Vds =07 V Vds =09 V Vds =11 V

Before

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds=01 VVds=03 VVds=05VVds=07 VVds=09 VVds=11 V

After

Gain asymp54

10

08

06

04

02

00

Vou

t (V)

50454035302520

Vin (V)

6

5

4

3

2

1

0

I (nA)

Vout

I

Inverter

Gain =54

K doping

10

8

6

4

2

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

Before K doping After K doping

Gain asymp 5

p-type

n-type

15

10

05

00V

out (

V)

252015100500

Vin (V)

Gain=5

Potassium Doping and CMOS InverterPotassium Doping and CMOS Inverter

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

CMOS NAND amp NORCMOS NAND amp NORIndividual back-gated

NOR NAND

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

10 μm 10 μm10 μm

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

N-type nanotube transistorsN-type nanotube transistorsHydrazine(NHydrazine(N22HH44) doping) doping

12

10

08

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds =01 V Vds =03 V Vds =05 V Vds =07 V Vds =09 V Vds =11 V

Before

06

04

02

00

I ds (μ

Α)

-10 -5 0 5 10Vg (V)

Vds=01 VVds=03 VVds=05VVds=07 VVds=09 VVds=11 V

After

Gain asymp54

10

08

06

04

02

00

Vou

t (V)

50454035302520

Vin (V)

6

5

4

3

2

1

0

I (nA)

Vout

I

Inverter

Gain =54

K doping

10

8

6

4

2

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

Before K doping After K doping

Gain asymp 5

p-type

n-type

15

10

05

00V

out (

V)

252015100500

Vin (V)

Gain=5

Potassium Doping and CMOS InverterPotassium Doping and CMOS Inverter

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

CMOS NAND amp NORCMOS NAND amp NORIndividual back-gated

NOR NAND

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

10 μm 10 μm10 μm

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

K doping

10

8

6

4

2

I ds (μ

Α)

-4 -2 0 2 4Vg (V)

Before K doping After K doping

Gain asymp 5

p-type

n-type

15

10

05

00V

out (

V)

252015100500

Vin (V)

Gain=5

Potassium Doping and CMOS InverterPotassium Doping and CMOS Inverter

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

CMOS NAND amp NORCMOS NAND amp NORIndividual back-gated

NOR NAND

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

10 μm 10 μm10 μm

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

CMOS NAND amp NORCMOS NAND amp NORIndividual back-gated

NOR NAND

10

08

06

04

02

00

Vou

t (V

)

Gate AGate B

11

10

01

00

10 μm 10 μm10 μm

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

httpwwwfibre2fashioncom Defense Science Journal Vol 55 No 2

Flexible electronics and smart textiles

Flexible electronics and smart textiles for ubiquitous computing and sensing for daily life and battle field applications

Carbon nanotubes due to their high flexibility and superior chemical sensing performances

Nature news

Robot with sensitive skin

Soldier in the future

Oak Ridge National Laboratory

Artificial muscle

11

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

1 Au layer deposition

2 Peeling off nanotubes

3 Transferring nanotubes

4 Etch away Au layer

Nanotube Transfer for Wearable ElectronicsNanotube Transfer for Wearable Electronics

Transferring yield of nanotubes Transferring yield of nanotubes congcong 100 100

Quartz

NanotubeThermal tape

Gold film

Target substrate

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

a Perpendicular transfer on SiSiO2

1st transferred layer

2st transferred layer

b 60 degree transfer

Carbon Nanotube ldquoFabricrdquoCarbon Nanotube ldquoFabricrdquo

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

On PETOn glass rod On Fabric

SEM image of transferred aligned SWNT

On glass slide

Nanotubes can be transferred on all kinds of substrates

Transferred nanotubes

Transferred nanotubes on various subTransferred nanotubes on various sub

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Wearable Transistors Transistor on FabricWearable Transistors Transistor on Fabric-20nm Ti back gate-TiAu as SD electrode-1microm SU8 as a dielectric

-onoff ratio cong 104

-Subthreshold swing(S) cong 500mVdecade

-14

-12

-10

-8

-6

-4

-2

0

I (μ

Α)

-5 -4 -3 -2 -1 0Vds (V)

5

4

3

2

1

625

20

15

10

05

00

I (μ

Α)

-20 -10 0 10 20Vg (V)

5

4

32

1

10-11

10-9

10-7

I (μ

Α)

-20 -10 0 10 20Vg (V)

10-9

10-8

10-7

10-6

10-5

I (μ

Α)

-20 -10 0 10 20Vg (V)

Before After

Electrical breakdown I ndashVg curves I ndashVds curves

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Wearable Transistors Chemical sensingWearable Transistors Chemical sensingTNT (Trinitrotoluene) sensing

-06

-04

-02

00

ΔG

G0

14x103121086420

time(s)

015 ppm02 ppm

04 ppm

06 ppm

11 ppm

23 ppb60 ppb

8ppb

Introduce gas

UV off

UV on

Detection limit asymp below ppb

TNTBenzene NO

+lightTiPd

Fabric coated withPolyethylene

NO2 sensing

025

020

015

010

005

000Δ

GG

0160012008004000

Time (sec)

80 ppb 150 ppb 125 ppm 25 ppm 5 ppm

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire TransistorsNanowire Transistors

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

SnO2

InP

Fe3O4

2 μm

InN

GaN

ZnO In2O3

CdO

Si

Adv Mat 15 143 (2003)Adv Mat 15 1754 (2003)APL 82 1950 (2003)

APL 88 133109 (2006) Nature Nanotech 2 378 (2007)Nano Letters 8 997 (2008)

Synthesis of Novel Nanowires

Nano Letters 4 1241 (2004)Nano Letters 4 2151 (2004)Adv Mat 17 1548 (2005)JACS 127 6 (2005)

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Evolution of Display technologies

1st

CRTInorganic ELElectron-Gun

PDP LCD

PlasmaColor FilterBack light

OLEDOrganic EL

Self-emitting

4th

FTNDFlexible amp Transparent

Display

Cutting-Edge Technology RequiredGenerations of Display Technologies

2nd 3rd

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Flexible Electronics

Portable and flexibleRigid heavy and breakable -gt Light unbreakable and flexible

Applications

WristbandDisplays

RollableNewspapers

Transparent Electronics

TransparentNontransparent -gt Transparent Easy-to-read

Applications

Head-up Displays

Transparent Monitors

Transparent Televisions

Windshields of cars

W i N d O W S

Paper Computers

Rollable Displays

Why Transparent and Flexible

Need New Materials to Achieve This Goal

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

α-Si TFTs - High Reliability- Presently used in LCDs- High Reliability- Presently used in LCDs

Poly-Si TFTs - High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs- High mobilities (~ gt150 cm2Vsec)- Presently used in AMOLEDs

Nanowires Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Overcome from (a) to (e)- High mobilities (~500-4000 cm2Vsec)- Low temperature processing can use on plastic substrate

Displays Advantage

- Low temperature processingcan use on plastic substrates

- Low temperature processingcan use on plastic substrates

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(a) High temperature processingdifficult to use on plastic

(b) Low mobilities (μ le 1 cm2Vsec)

(c) High temperature processingdifficult to use on plastic substrates

(c) High temperature processingdifficult to use on plastic substrates

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

No Current Development (High Risk)- Nanowire alignmentassembly- Uniformity- Yield

ChallengeRequired Solution

(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity(d) Low mobilities (μ le 1 cm2Vsec)(e) Temperature and moisture sensitivity

ldquoNew Display Concepts using Hybrid Organic-Nanowire Structuresrdquo

Includes all advantages of current flat panel displays (LCD PDP AMOLED) and overcomes conventional displayrsquos limitations

Why Nanowires

OTFTs

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Synthesis of In2O3 Nanowires Laser AblationSynthesis of In2O3 Nanowires Laser Ablation

AFM image of Au clusters on SiSiO2

2 μm

InAs Target

In2O3 nanowires

Length 3 ndash 5 μm

Zhou et al Adv Mat 15 143 (2003)

Growth conditionT 770 oC

Pressure 100 ndash 700 Torr

Gas Ar + O2

LaserGas

Substrate with Au clusters

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

In2O3 Nanowires Material AnalysisIn2O3 Nanowires Material Analysis

XRD TEM highXRD TEM high--resolution TEMresolution TEM

Cubic crystal structure a = 101 nmGrowth direction [110]Advantage no amorphous coating reliable electrical contacts and operation

072nm

[110]

100 nm

[110]

AuIn Particle

Inte

nsity

(a u

)

60504030202 theta (degree)

In2O3 (222)

In2O3 (400)

In2O3 (440)

Au (111) Au (200)

In2O3 (622)

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

In2O3 Nanowire TransistorIn2O3 Nanowire Transistor

1 N-type semiconductor due to oxygen vacancies and In interstitials2 On off ratio 11 times 105

1000

500

0

-500

-1000

I (nA

)

-10 -05 00 05 10Vds (V)

10 V

V g = 15 V

7 V 0 V

-7 V

-10 V

600

400

200

0I (

nA)

1050-5-10Vg (V)

Vds = 032 V300 K

APL 82 112 (2003)

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Fully transparent transistor using oxide nanowiresFully transparent transistor using oxide nanowires

15 um

ITO S

ITO D

IZO G

In2O3 NWDiameter ~20 nm

In2O3 nanowire as transparent transistor active channel

bull Highly transparent (intrinsic transparency amp small dimension)

bull Low temperature processbull High mobility (single crystal)

In2O3 NWALD Al2O3ltDevice structuregt

Nature Nanotechnology 2007

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

High performance transistorHigh performance transistor

Mobility 514 to 300 cm2VsSubthreshold 160 mVdecOnoff ratio 106

Transmittance ~82 (including substrate)

Nature Nanotechnology 2007

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Transparent amp flexible transistorsTransparent amp flexible transistors

Device on PET

Mobility 120 to 167 cm2VsSubthreshold 900 mVdecOnoff ratio 105

Nature Nanotechnology 2007

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Application of transparent transistors for AMOLED circuitApplication of transparent transistors for AMOLED circuit

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

Scan

T1T3

Data (Vg2)

Cst

(Vg1)

T2

Vdd

OLED

(a) (b) (c)

Highlights of Recent Results Initial Circuit Demonstration (Green AM OLED Display)

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Chemical Sensing Based on In2O3 NanowiresChemical Sensing Based on In2O3 Nanowires

ON

In

In2O3nanowire

SiSiO2 back gate

TiAu electrodes

Advantage of In2O3 nanowires1 Single crystal 2 No amorphous coating (as compared to Si NWs with amorphous SiO2)3 High surface-to-volume ratio

Operation principle NO2 molecules withdraw electrons from In2O3Operation principle NO2 molecules withdraw electrons from In2O3

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

A UV light illumination to recover the deviceB turn off UV C 20ppb NO2Ar

20ppb NO2 in air can be detectableDetect limit can be pushed to 5ppb NO2 in Ar

NO2 Sensing Based on In2O3 NanowiresNO2 Sensing Based on In2O3 NanowiresReal time detection and recovery using UV illumination

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

In2O3 Nanowire Sensors with Integrated HeatersIn2O3 Nanowire Sensors with Integrated Heaters

80

60

40

20

0

Nor

mal

ized

Con

duct

ance

()

4003002001000Time (s)

50 ppm20 ppm10 ppm1 ppm

Advantages

Ethanol Alcohol

Sensitive to hydrocarbonsFaster recoveryPotential to achieve good selectivity

heater

SiN membrane

sensor

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

OUTLINEOUTLINEIntroductionIntroduction

Carbon NanotubesCarbon NanotubesCarbon Nanotube InverterCarbon Nanotube InverterAligned Growth and NanotubeAligned Growth and Nanotube--onon--Insulator (NOI) Insulator (NOI) ApproachApproach

NanowiresNanowiresNanowire SynthesisNanowire SynthesisNanowire Transistors and MemoriesNanowire Transistors and Memories

ApplicationsApplicationsBiosensingBiosensingEnergy ConversionEnergy Conversion

ConclusionConclusion

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Nano-Biosensor and Nano-DiagnosisNano-Biosensor and Nano-Diagnosis

AdvantagesSmall nanoscale in-vivoSelectiveSensitive No amplification neededCheap disposableVersatileintegratable

ElectrodeNanowire Nanotube

Si Substrate

SiO2

Antigen

Antibody

Linker

Structure and PrincipleNanowire nanotube functionalized with linking moleculesProbe molecules (ss-DNA antibody) anchored to the surface via linkersSelective attachment of target molecules leads to a chemical gating effectResistance of the nanowire nanotube used as read-out

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Detection of Prostate Specific Antigen (PSA)Detection of Prostate Specific Antigen (PSA)

Si

AuTi

SiO2

PSA

PSAantibody

Linker

PSA

NWSWNT

(a)

NO O

OP

O O

O O

OP

O O

H O O

OP

O O

H N O

In2O3 NWi iiiii

(b)

O

O

NO

O

O

H N

SWNT iv v

(c)

PSA is a bio marker for the presence of prostate cancer which is the most frequently diagnosed cancer among

men in the US

Standard PSA

Probability of cancer

0-2 ngmL 12-4 ngmL 154-10 ngmL 25gt10 ngmL gt50

In2O3 Nanowire functionalization

Carbon Nanotube functionalization

In collaboration with Richard Cote of USC Center for Cancer ResearchIn collaboration with Richard Cote of USC Center for Cancer Research

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Selective Detection of Selective Detection of PSA PSA in PBS Bufferin PBS Buffer

Buffer BSA PSA

(a)

390

385

380

I (n

A)

5004003002001000Time (s)

252

248

244

240

I (μΑ

)

3000200010000Time (s)

BSA PSABuffer

(b)

Carbon Nanotube Mat Carbon Nanotube Mat Reduced ConductionReduced Conduction

Individual InIndividual In22OO33 Nanowire Nanowire Enhanced ConductionEnhanced Conduction

11 No response when BSA was addedNo response when BSA was added22 Detection of PSA down to 5 Detection of PSA down to 5 ngmLngmL achieved in PBS bufferachieved in PBS buffer

RealReal--time detection of PSA in aqueous environmenttime detection of PSA in aqueous environment

J Am Chem Soc 2005 127(36) 12484

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Integration of nanobiosensor and advanced microfluidics toward multiplexed sensingIntegration of nanobiosensor and advanced microfluidics toward multiplexed sensing

Microfabricatedvalves

Device region

functionalize nanobiosensor selectively using microfluidics system

Ab 1 Ab 2 Ab 3

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Integrated sensor and microfluidicsIntegrated sensor and microfluidics

source

drain

valves

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

-Higher Flexibility than ITO

-Transparent

-Most abundant element in nature

-Tunable eletronic properties

using Chemical treatment and enhanced carrier injection

CNT films as transparent conductive electrodes for Solar cell

Carbon Carbon NNanotubes for anotubes for EEnergy nergy CConversion onversion ((Solar cellSolar cell))

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Fabrication of CNT films

On Glass On Plastic Sub

CNT films on Filter membrane

Filter

PDMS

New Sub

PDMS

Dissolve arc discharge nanotubes In 1 SDS DI water (1mgml) using probesonicatorbullDilute by 30times with DI waterbullFiltration of this solution

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Application in Solar cell

AbsorptionExciton DiffusionCharge Separation

Exciton DissociationCharge Transport

Charge CollectionCathode (Electron)Anode (Hole) E

(eV

)

Evac = 0 eV

TCE CuPc C60 BCP

Al

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Plastic

CNT films

CuPc(donor)

C60 (acceptor)

BCP(Buffer)

Al

Application in Solar cell

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Device Structure Jsc (mAcm-2) Voc (V) FFEfficiency

()

PlasticITOOrganicAl 20 0410 051 037

PlasticSWNTHigh TransOrganicAl 22 0397 044 032

PlasticSWNTLow TransOrganicAl 14 0365 043 019

PEDOTPSSCuPcC60BCP

-04 -02 00 02 04 06

-2

-1

0

1

2 SWNTHigh Trans Dark SWNTHigh Trans Light SWNTLow Trans Dark SWNTLow Trans Light ITO Dark ITO Light

Voltage (V)

Cur

rent

den

sity

(mA

cm-2)

400 500 600 700 800 900 1000 1100

0

10

20

30

40

50

60

70

80

90Tr

ansm

ittan

ce (

)

Wavelength (nm)

PlasticSWNTHigh Trans

PlasticSWNTLow Trans

PlasticITO

In spite of the low SWNT transmittance this is comparable to the 20 mAcm-2 Jsc and 037 efficiency obtained from an identical device based on a 71 transmissive plasticIn2O3Sn electrode which underscores the prospect for improving OPVs by utilizing SWNT electrodes

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

Summary

1 Built one of the first integrated carbon nanotube inverter

2 Demonstrated growth of aligned single-walled carbon nanotubes and developed a nanotube-on-insulator approach

3 Developed a laser ablation approach for the synthesis of metal oxide nanowires

4 Demonstrated In2O3 nanowire transistor multilevel memory and chemical sensors

5 Nanotubes and nanowires have been used for complementary sensing of PSA

6 Nanotubes have been used as transparent conductive electrodes for solar cell

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU

THANK YOU THANK YOU

httphttpnanolabuscedunanolabuscedu

• Carbon Nanotubes and Oxide Nanowires Synthesis Properties and Applications
• OUTLINE
• Original MotivationMoorersquos Law
• MOLECULAR STRUCTURE
• Benchmarking CNT FETs
• Nanotube Transistor Research
• OUTLINE
• Traditional approach On-Site Synthesis of Single-Walled Carbon Nanotubes
• Integrated Nanotube SystemsComplementary Carbon Nanotube Inverter
• Aligned Nanotubes for Devices and Circuits
• Synthesis of Aligned Nanotubes on Sapphire Quartz
• Aligned Nanotubes Grown on a-Plane Sapphire
• Control of Nanotube Density
• Hypothetic Schematic Diagram of SWNT on a-Plane Sapphire
• Calculation of Lennard-Jones Potential
• OUTLINE
• Comparison between Silicon-on-insulator (SOI) and Nanotube-on-Insulator (NOI)
• Wafer-Scale CNT Transfer
• Wafer-Scale Aligned Nanotube Device Fabrication
• Back-Gated Submicron Transistors
• Top-Gated Submicron Transistors
• N-type nanotube transistors
• Potassium Doping and CMOS Inverter
• CMOS NAND amp NOR
• OUTLINE
• Synthesis of In2O3 Nanowires Laser Ablation
• In2O3 Nanowires Material Analysis
• In2O3 Nanowire Transistor
• Fully transparent transistor using oxide nanowires
• High performance transistor
• Transparent amp flexible transistors
• Application of transparent transistors for AMOLED circuit
• Chemical Sensing Based on In2O3 Nanowires
• OUTLINE
• Nano-Biosensor and Nano-Diagnosis
• Detection of Prostate Specific Antigen (PSA)
• Integration of nanobiosensor and advanced microfluidics toward multiplexed sensing
• Integrated sensor and microfluidics
• THANK YOU