lecture: tuesday/thursday 9:30 – 10:45 mueunjae memorial hall,...

AMSE 609Advanced Electron MicroscopyAdvanced Electron Microscopy

Spring 2010

•　Lecture: Tuesday/Thursday 9:30 – 10:45Mueunjae Memorial Hall, Room 305

•　Instructor: Prof. Sang Ho Oh, Room 319, Bldg #1Tel: 279-2144, E-mail: [email protected]

AMSE 609 Spring 2010

Course Objectivej• Goals:

- In depth understanding of fundamentals of scattering, diffraction and imaging.

- Understand three major TEM image forming principles, i.e. diffraction/phase/STEM Z-contrast imaging

- Introduce electron spectroscopy and spectroscopic imaging- Introduce electron spectroscopy and spectroscopic imaging

- Get specialized with TEM technique(s) that you use most

- Keep up with current progress in TEM instrumentation and Keep up with current progress in TEM instrumentation and advances in TEM characterization


Course Mechanisms• Prerequisite:

MUST l t AMSE 608 b f h d

• Grading policy:

- MUST complete AMSE 608 beforehand

- Attendance and class activity 20%- Reading assignments and homework 30%

TEM Laboratories and term paper 50%- TEM Laboratories and term paper 50%

Term project: Chose TEM technique(s) (not limited to those covered in this course) and a material system (you may want to work on your own ) y (y y ysample) that you wish to study more deeply. Submit 1 page abstract by April 8 and term paper by June 1. The writing guideline for term paper will be given later in class. Self-operation of TEM is highly recommended. will be given later in class. Self operation of TEM is highly recommended. Extra points will be added for those accompanied by quantitative interpretation based on simulations. All submission and presentation should be given in English


should be given in English.

Course ContentsI. ELASTIC ELECTRON SCATTERING: IMAGING

1. Diffraction contrast1 1 Kinematical diffraction theory1.1. Kinematical diffraction theory1.2. Dynamical diffraction theory1.3. Defect analysis: Dislocations and twins

2. Phase contrast2. Phase contrast2.1. Image formation theory of HRTEM2.2. Simulation of HRTEM images2.3. Aberration function and practical correctionp2.4. Phase retrieval by exit-wave reconstruction of HRTEM2.5. Other phase contrast techniques

3. STEM Z-contrast3.1. Image formation theory of HADDF Z-contrast3.2. Simulation of HAADF Z-contrast image

II. INELASTIC ELECTRON SCATTERING: SPECTROSCOPY1. EELS and EDS2. Spectroscopic imaging

AMSE 609 Spring 2010III. TERM PRESENTATION

Text book• Lecture note:

Will be uploaded at e-class a day advance

1 D id B Willi C B C t “T i i El t

• References:

Will be uploaded at e class a day advance

1. David B. Williams, C. Barry Carter, “Transmission Electron Microscopy”, 2nd edition, Springer (2009).

2. Brent Fultz, James M. Howe, “Transmission Electron Microscopy and Diffractometry of Materials”, 3rd edition, Springer (2008).

3. Peter R. Buseck, John M. Cowley, Leory Eyring, “High-Resolution Transmission Electron Microscopy and Associated Techniques” Transmission Electron Microscopy and Associated Techniques , Oxford University Press (1998).

4. Ludwig Reimer, Helmut Kohl, “Transmission Electron Microscopy: Physics of Image Formation”, 5th edition, Springer (2008).

5. John C. H. Spence, “High-Resolution Electron Microscopy”, 3rd

edition, Oxford Science Publications (2003).


edition, Oxford Science Publications (2003).

About me…• Education:

- B. S. – Han Yang University (1996)- M. S. – POSTECH (1998)- Ph.D. – POSTECH (2002)

• Professional Experiences:- Post doctoral research – Max-Planck Institute @ Stuttgart, Germany

Senior Researcher KRISS @ Daejeon Korea- Senior Researcher – KRISS @ Daejeon, Korea- Researcher – Erich Schmid Institute @ Leoben, Austria- Researcher – Oak Ridge National Lab @ Oak Ridge, TN, US- Senior Researcher – KBSI @ Daejeon, Korea- Assistant Prof @ POSTECH since July 2009

• Research Expertise:- Crystalline defects, crystal growth, thin films, perovskite oxides, electron

microscopy size effects mechanical behavior nanostructured materials


microscopy, size effects, mechanical behavior, nanostructured materials

What can you do with a TEM?


What can you do with a TEM?y

• Selected Area Selected Area Diffraction (SAD)

C t ll hi t t - Crystallographic structure from particular areas of a sample.p

- Used to distinguish and identify crystalline (and amorphous) phases in a material.

Selected area diffraction pattern110 Zone axis pattern of a f.c.c. Au film

P tt l d bl t i i i th A fil

- Wave description of diffraction


Pattern reveals double twining in the Au film

What can you do with a TEM?y• Convergent Beam El t Diff ti Electron Diffraction (CBED)

- Point and Space Group determination

- Local strain

- Nanoscale diffraction

Convergent beam electron diffraction pattern

111 Z i tt f ili


111 Zone axis pattern of silicon

Note detailed structure in the central disck


• Large-angle • Large-angle Convergent Beam Electron Diffraction Electron Diffraction (LACBED)

- Misorientation across grain boundaries

- Dislocation Burgers vector

- Crystalline symmetry



• Diffraction Contrast Imaging

• Strain fieldsStrain fields- Dislocations

- Stacking faults- Stacking faults

- Grain boundaries

- PrecipitatesPrecipitates

- Second phases

Typical bright field imageDislocation configuration at the interface between a SiGe heteroepitaxial layer and a Si (100) substrate

- Dynamical diffraction theory- Intensity of diffracted beam

D f t l i


p y ( )viewed in plan view (along [100])- Defect analysis


• Diffraction Contrast Imaging

• One beam selected One beam selected for imaging

T itt d “b i ht fi ld”- Transmitted – “bright field”

- Diffracted – “dark field”



Bright field image Dark field image ‘Weak beam’ dark field image


dark field image

What can you do with a TEM?y• High-resolution imagingimaging

• Atomic column i t l ti images at resolutions from 0.7Å and above

- Interference of transmitted and diffracted electron diffracted electron waves

High resolution micrograph of a copper-sapphire interface- Contrast Transfer Function

- Image simulation (Thickness-defocus map)- Contrast delocalization

Aberration (Cs) correction


- Aberration (Cs) correction- Exit wave reconstruction


Electron • Electron holographyM th • Map the mean inner potential

f t i lof a material



• High angle annular g gdark field (HADDF) imaging

Au nanoparticles in a Al2O3 film

g g

- Accomplished in a dedicated Scanning

Au

gTEM (STEM)

- Collects incoherent Al2O3

Siscatter, yields atomic resolution

Au

Si

Au nanoparticleson a Si nanowire

- Image forming theory

I i l ti ( / h )


- Image simulation (w/ phonon)


Electron energy loss • Electron energy loss spectroscopy

- Measures the amount of energy lost by the incident electrons.

- Similar spatial l ti resolution, energy

resolution of ≈ 1 eV.

- Probes density of state Probes density of state (DOS) locally.

EELS spectrum from CaCO


EELS spectrum from CaCO3


Energy Filtered • Energy Filtered Imaging

- Zero loss imaging removes inelastically scattered electrons from image La M edge Ti L edgeelectrons from image

- Selective imaging of electrons that have lost a electrons that have lost a particular energy

- Most commonly used to

LaSrMnO3/SrTiO3 thin film

Mn L edge A+B+Ccreate a map of local (≈ 1 nm) chemistry


3 3


• Dynamical behavior- Possible to apply many type of

stimuli to samples during simultaneous imagingsimultaneous imaging

- Probe interrelationships between structure-properties between structure properties and processing

- Stimuli include:• Temperatures to 1300 oC• Temperature to LN2• Chemical flux

N i l ti

Dissociation of ZnO crystal at 360 oC under high energy (1 25 MeV) electron beam

• Nanomanipulation• Nanoindentation• Electrical bias in combination with

heating


high energy (1.25 MeV) electron beamheating• Uniaxial strain

A Way to organize our thoughtsy g g• In AMES 609, we will cover:

- Elastic & inelastic scattering

- Diffraction• Single scattering

(kinematical)• Multiple scattering

(dynamical)(dynamical)

- Image formation:• Diffraction contrast• Phase contrast• Incoherent imaging

- Spectroscopy:p py• Energy Dispersive X-ray Spectroscopy• Electron Energy Loss Spectroscopy


Coming up in next classg p• Basic properties of electrons: A quick reminder…

- Wave-particle duality- Wave-particle duality

h hp mv

Every particle with mass m and momentum p (velocity v ) can be described by a wave with wavelength λ.　

p mv

• Elastic scattering- Particle perspective - Wave perspectiveParticle perspective Wave perspective


lecture: tuesday/thursday 9:30 – 10:45 mueunjae memorial hall,...

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