Carbon Nanotube Synthesis By Thermal CVD method- M.G.Moinuddin

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CNT Synthesis by Thermal CVD method & its’ Characterization Jamia Millia Islamia Central University India Presentad by- Mohd.Ghulam.Moinuddin M.Sc Electronics(2015)

Transcript of Carbon Nanotube Synthesis By Thermal CVD method- M.G.Moinuddin

Page 1: Carbon Nanotube Synthesis By Thermal CVD method- M.G.Moinuddin

CNT Synthesis by Thermal CVD method

&

its’ Characterization

Jamia Millia IslamiaCentral University India

Presentad by-Mohd.Ghulam.Moinuddin

M.Sc Electronics(2015)

Page 2: Carbon Nanotube Synthesis By Thermal CVD method- M.G.Moinuddin

Points aimed in this presentation

• Physics of CNT.

• Synthesis of Carbon nanotubes.

• Role of catalyst in growth.

• Catalyst and their role for synthesis

• Result analysis

Page 3: Carbon Nanotube Synthesis By Thermal CVD method- M.G.Moinuddin

Carbon nanotubesA 1D structures

• Carbon nanotubes (CNTs) are allotropes of carbon.

• CNT can be described as a sheet of graphite rolled into a cylinder

• Constructed from hexagonal rings of carbon.

• Can have one layer or multiple layers-

SINGLE WALL NANOTUBE(SWNT), MULTIWALL NANOTUBE(MWNT)

Great applications in nanotechnology, electronics, optics.

Page 4: Carbon Nanotube Synthesis By Thermal CVD method- M.G.Moinuddin

Physical structure of CNT

Armchair (n,m) = (5,5)

= 30

Zig Zag (n,m) = (9,0)

= 0

Chiral (n,m) = (10,5)

0 < < 30

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Physical properties of CNTs-

Conductivity and strength

- “current-carrying capacity is 1000 times higher than that of copper...” due to more electron than and metallic surface

- As hard as the diamond in fact twice harder than pure diamond.

100 times stronger than stainless steel and six times lighter.

Thermal stability & reliability

CNT is thermally stable up to 4000K.

Smart Sensors

Sensitive to make – sensor

Chemically active, highly sensitive towards light

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Chemical Vapour Deposition

Page 7: Carbon Nanotube Synthesis By Thermal CVD method- M.G.Moinuddin

• Commercial method for production of carbon nanotubes

• Substrate is prepared with a layer of metal catalyst particles(mostly

nickel, cobalt, iron, or a combination)

• Diameters of the nanotubes depends on the size of the metal particles

• Two gases are flown into the reactor:

– a process gas (such as ammonia, argon nitrogen or hydrogen) and

– a precursor gas (such as acetylene, e thylene, ethanol or methane)

• Substrate is now heated to ~ 800°C

which initiate the growth of nanotubes

Chemical Vapour Deposition

Page 8: Carbon Nanotube Synthesis By Thermal CVD method- M.G.Moinuddin

Growth mechanism of CNT

Tip growth

Bottom growth

Page 9: Carbon Nanotube Synthesis By Thermal CVD method- M.G.Moinuddin

Growth Duration-

Page 10: Carbon Nanotube Synthesis By Thermal CVD method- M.G.Moinuddin

Experimental ApproachTo control the growth density of

cnt at constant temperature we

change the catalytic ratio for best

output. Ratio of catalysts-

Fe: Co 2:1

1:1

2:3

3:2

Page 11: Carbon Nanotube Synthesis By Thermal CVD method- M.G.Moinuddin

Role of catayst

• Surface to volume ratio

- A 30 nm particle only 5% on the surface

- A 10 nm particle 20% on the surface

- A 3 nm iron particle has 50% atoms on the surface

Redius of the range of 1.2 Ao

Crystalline arrangement With 30nm range

Page 12: Carbon Nanotube Synthesis By Thermal CVD method- M.G.Moinuddin

Chemical and physical structure of

CATALYST

Page 13: Carbon Nanotube Synthesis By Thermal CVD method- M.G.Moinuddin

Growth approach of CNT

MWCNTs grown at low temperatures and atmospheric pressure

, M. Kumar and Y. Ando, Carbon 43, 533

High quality TEM analysis at the time of experiment occur reported by –

reference cited

Page 14: Carbon Nanotube Synthesis By Thermal CVD method- M.G.Moinuddin

Solubility of catalyst with precursors-

Annealing

Oxidisation

at 600 oC

After C2H2

Ref - J. Phys. Chem. C 2009, 113, 1648–1656

• Formation of cnt depends over

temp as well as catalytic

solubility .

• A binding energy analysis xps

is shown here

Fe3C

Page 15: Carbon Nanotube Synthesis By Thermal CVD method- M.G.Moinuddin

Experimental approach during synthesis -

We analysed different parameter like ratio

and concentration of catalyst solution.

Independent catalytic conc.

i) Fe:Co 6:1 .12 : .02 gram/100ml.14g/100ml

ii) Fe:Co 3:1 .12:.04 gram/100ml .16g/100ml

iii) Fe:Co 2:1 .12:.06 gram/100ml .18g/100ml

iv) Fe:Co 2:3 .12:.08 gram/100ml .20g/100ml

v) Fe:Co 1:1 .

12:.12 gram/100ml .24g/100ml

Constant catalytic

i) Fe:Co 6:1

.1350 :026gram/100ml.16g/100ml

ii) Fe:Co 3:1 .12:04gram/100ml.16g/100ml

iii) Fe:Co 1:2..10:06gram/100ml.16g/100ml

iv) Fe:Co 1:1 .08:08gram/100ml.16g/100ml

v) Fe:Co 1:2

.05 :10gram/100ml.16g/100ml

Ratio of catalyst Fe:Co concentration

Page 16: Carbon Nanotube Synthesis By Thermal CVD method- M.G.Moinuddin

Experimental Result analysis

FeSEM (Field effect

scan electron microscopy)Raman Spectroscopy

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Sem Result experiment 1-

Fig1Fe:Co: 3:1: Fig2Fe:Co: :2:1:

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Fig3 Fe:Co 3:2

SEM images of CNT grown at .16/100 g/ml

catalytic concentration. a) 1um b) 500nm

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Fig3 Fe:Co 3:2

sem image of highly dense

MWCNT from Sigma

Aldrich China

SEM images of CNT grown at .16/100 g/ml

catalytic concentration. a) 1um b) 500nm

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Experiment 2-

Fig4 SEM image taken at a) 10um b) 2um resolutions CNT growth Fe:Co 1:1 with

.016/100 g/ml

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.32mm

Analysis the length of differently grown CNT

-Reported as 0.32 mm

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Raman analysis of catalytic environment CNT

growth.

Raman spectra of CNT

grown by exp. 1Raman spectra of CNT

grown by exp. 2

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Result

• A complete SEM and Raman analysis show that the with

changing the concentration the diameter as well as quality

changes its.

• For prior concentration the diameter dicreses till a idealized

value (.16g/100) then due to diffusion hindrance the dia meter

of CNT drastically increase and quality goes down .

• SEM Analysis is used

for morphological analysis

and Raman is used for

Qualitative analysis (G and

D band.

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Conclusion-

By the physical characterization of grown CNT

we can conclude that- CNT Synthesis not only depends upon catalyst, but orientation

of catalyst promoter also.

The quality of CNT (density, alignment , length, diameter ) are

better in condition with catalyst promoter.

This is only myth that catalyst are unaffected after reaction .

Post synthesis report shows that the iron particle reacts with

carbon and a certain part of carbon is made as Fe3C.

The high temperature converts metal oxide to metal which are

best for high quality CNT synthesis.

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References• Topics in Applied Physics-

Carbon Nanotubes: Synthesis, Structure, Properties and Applications

M.S. Dresselhaus, G. Dresselhaus, Ph. Avouris

• Iijima S 1991- Nature 354-

• Effect of catalyst film thickness on carbon nanotube growth by

selective area chemical vapor deposition; Y. Y. Wei, Gyula Eres, V. I.

Merkulov, and D. H. Lowndes Citation: Applied Physics Letters 78, 1394

(2001); doi:10.1063/1.135465.

• N. Tripathi, P. Mishra, Harsh and S.S Islam, Physics of Semiconductor

Devices (Environmental Science and Engineering ), ;645 (2014).

• N. Tripathi, P. Mishra, Harsh and S.S Islam, Applied Nanoscience,; DOI

10.1007/s13204-013-0288-8(2014)

• review paper -Carbon Nanotube Synthesis and Growth Mechanism , Mukul

Kumar

Special thanks to fppt.com for ppt temples.

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Question please…