Transmission Electron Microscopy (TEM) Introduction, Application and Operation

Longzhou Ma, PhD.Harry Reid Center for Environmental Studies (HRC)University of Nevada Las Vegaslma@unlv.nevada.eduPhone:702-895-2024Download: http://nstg.nevada.edu/TEM/TEMedu.htmfor section 1, 2 and operation safety document.

Place: HRC 144 Conference RoomTime and Date: ♦ 10:30-11:30 AM, Wednesday, Aug 18. 2010

♦ 1:30-2:30 PM, Thursday, Aug 19. 2010

Training Course (I)

TEM BasicsTEM Basics

TEM Image Mode TEM Image Mode

InIn--situ TEMsitu TEM

TECNAI-F30 Super-twin TEM Components, Interfaces and Operations

Sample Preparation

Outline

TEM Basics

TEM Image Mode

In-situ TEM

Part I

Microscopy is one of few methodologies applied to nearly every field of science and technology in use today.

By means of microscopy, scientists and students can explore the synergistic relationships of structure and properties of a wide variety materials in both the physical and Life Sciences.

Using which type of microscope depending what resolution you need

Optical microscope

Electron microscope

Microscopy and Science

Basic Principle of Microscope

EM usually have two condenser lenses

Current, I, in coil

Magnetic field, B

How EM Works?

( )( )Bve

BvEqdtrdmF

rr

rrr

rr

×=

×+=

= 2

2

How EM Works?

Illumination system

Objective lens and stage

Observation /imaging system

Microscope Resolution:

The minimum resolvable distance between the image of two point objects using a perfect lens.

Resolution of an imaging system ( Abbe’s equation)

λ: wavelength of the imaging radiation

η: index of refraction of the lens

α: illumination semi-angle

α

λ

( )αηλρ

sin61.0

=

Why Electron Source ?

Light vs. Electron

Light Microscope Electron Microscope

λ =0.5 µm λ =√150/Vo =0.055 Ǻ(@50 kv)

η= 1.5 (glass) η= 1.0 (vacuum)

α=70° α=1°

ρ =0.2 µm=2000 Ǻ ρ=0.00016 µm=1.6 Ǻ

Why Electron Source ?

Light vs. Electron

Why Electron Source ?

Information of EM ?

EM PrinciplesElectron-Sample Interactions

Incident e- Beam

Backscattered e-

Auger e- Secondary e-

Inelasticallyscattered e-

Unscattered e-

Elastically scattered e-

Transmitted ElectronsContrast Transfer Function

X-rays Cathodaluminescence

Sample TEM Sample Thickness = 50-100 nm

EDX

EELS

SEM

TEM

Electron Microscope

Specimen

Scanning Electron Microscope (SEM) Dealing mainly with Surface

Electron Beam

Backscattered Secondary Electron to Image Specimen Topography

Transmission Electron Microscope (TEM) Dealing mainly with Internal Structure

Transmitted and Diffracted Electron to Image Specimen Internal Structure

Tecnai-F30 Super-twin TEM

Specification300 KV Acceleration Voltage

Field Emission Gun

Magnification: 60x—1000 Kx

Resolution: 0.2 nm

Loaded with Various Detectors

Tecnai-F30 Super-twin TEM

An Example of TEM Application for Ni-based Superalloy 783: explore internal microstructure (Ma, Chang, et al: Met. Trans. 2003)

10µm

Isothermally exposure at 500°C for 3000 hours Standard Heat-treatment

Optical Micrograph with Grain Size of 35-40 µm

Information of EM ?

10µm 10µm 10µm 10µm

Isothermally exposure at 500°C for 3000 hours Standard Heat-treatment

SEM Micrograph of β phase

β phase

Isothermally exposure at 500°C for 3000 hours Standard Heat-treatmentshowing internal precipitates

TEM Micrograph of β phase

Information from TEM

Image

Structure

Chemistry

Image contrast tells information

Morphology and Dimension

Defects and Microstructures

Image

Image

CNT Crept alloy 230

Nano-particle

Structure

FFTFFT 2Th Degrees80706050403020

Sqr

t(Cou

nts)

500

450

400

350

300

250

200

150

100

50

0

-50

Si-SRM 640c 14.75 %Cryptomelane 85.25 %*

**

* * *

*

6.99

Å (1

10)

4.94

Å (0

20)

3.13

Å (3

10)

2.40

Å (2

11)

2.16

Å (0

31)

1.84

Å (4

11)

1.54

Å (2

51)

2 Theta (°)2Th Degrees80706050403020

Sqr

t(Cou

nts)

500

450

400

350

300

250

200

150

100

50

0

-50

Si-SRM 640c 14.75 %Cryptomelane 85.25 %*

**

* * *

*

6.99

Å (1

10)

4.94

Å (0

20)

3.13

Å (3

10)

2.40

Å (2

11)

2.16

Å (0

31)

1.84

Å (4

11)

1.54

Å (2

51)

2 Theta (°)

Crystal Structure MnO2 Cryptomelane, L. Ma, T. Hartmann, etal Microscopy and Microanalysis, Aug. 2008

Dough-like structure and Double-Helices-type Modification

O2

Tetragonal space group I4/m witha=9.897(1) Å and c=2.852(1) Å

Simulated image showing helix structure due to multi-layer contrast

Structure

HRSTEM image showing Si dumbbell structure along [110]

d (110)

Chemistry

Energy (keV)

Cou

nts

151050

200

150

100

50

0

Al

Si

Co

Co

Co

Ni

Ni

Ni

TiTi

Fe

Fe

EDX HAADF Detector Point 3

Energy (keV)

Cou

nts

151050

300

200

100

0Al Cr

Cr

Fe

Fe

Ni

Ni Nb NbNbNbNb

Co

CoCo

EDX HAADF Detector Point 1

Energy (keV)

Cou

nts

15105

300

200

100

0

AlFe

Fe

Ni

Ni

Ni

TiTiCrCr

Co

Co

EDX HAADF Detector Point 2

Energy (keV)

Cou

nts

15105

150

100

50

0

Al

Fe

Fe

Ni

Ni

Ni

TiTiCrCr

Co

Co

EDX HAADF Detector Point 4

EDX Analysis for Alloy 783 Showing that β phase Contains Al

2 um1

2

3

4

Chemistry

EEL at 190 eV

Boron K

EEL at 285 eV

Carbon K

EEL at 418eV

Nitrogen K

Electron Energy Loss Spectrum (EELS) of B-N-C Film

Chemistry and Structure

EELS Mapping image: IBM R & D center, 2004

Chemistry and Structure

EELS Mapping image: IBM R & D center, 2004

50 nm

TEM Image Mode

TEM Modes

Bright Field Image Mode

Dark Field Image Mode

Diffraction Mode

HRTEM Mode

STEM and Analysis Mode

In-situ TEM

Illumination system:

Objective lens and stage

Observation /imaging system

Beam condition determines TEM mode

TEM Ray Diagram

• Illumination system

• Imaging system

BF Mode (diffraction contrast image)

Parallel beam

Most often used mode

Parallel beam

Imaging with the diffracted beam

DF Mode (diffraction contrast image)

Diffraction Mode

Parallel beam

Only use intermediate lens

Change focal strength

Summary

Example ZrO2 micro-crystalline

BF DFSAD

HRTEM Mode (Phase contrast image)

Alumunisilicate Waste Form

G. Cerefice and L. Ma, Met. Trans. 2009

• Parallel Beam

• Many beams imaging

STEM Mode (Z-contrast image)

• Convergent Beam

Convergent Beam

CBED (Convergent Beam Electron Diffraction)

STEM and Analytical Mode

In-situ TEM

In-situ Nano-indentation system

• Provided by Nanofactory Instruments, Sweden

• Single Tilt Nano-indenter holder with heating stage for µN force-displacement probing and TEM imaging

• AFM-TEM holder for nN force, electrical probing and AFM imaging

• STM-TEM indenter holder for electrical probing, manipulation and STM imaging

In-situ TEM

In-situ TEM

In-situ TEMDiamond tip

Layered specimen

50 nm

In situ TEM nano-indentation

In-situ TEM: nano-indentation

In-situ TEM: nano-particle transportation

W-assisted joining two DWNTs in “ plumbing double wall carbon tube), by 3-D manipulation mode of STM-TEM holder, C. Jin, et al. Nature Nanotech. 2008

10 nm

In-situ TEM: CNT welding and Pressing

In-situ TEM: CNT Bias Measurement

In-situ TEM: Tensile

Courtesy : Oleg. Nanofactory

Questions?