CHAPTER 1 The Modern Microscope Today 1
1 Introduction 1
2 Microscope Development 2
3 The Modern Microscope 3
3.1 Introduction 3
3.2 Electron optics: Lenses 5
3.3 Electron Optics: Microscope 12
3.4 Vacuum System 21
3.5 Image Acquisition 25
3.6 Energy Filtering 32
4 Microscopes in the Future 36
4.1 Monochromators: Improving the Energy Spread 36
4.2 Cs Correctors: Improving the Spherical Aberration Coefficient 38
4.3 Computer Control: Automated and Remote Operation 39
References 41
CHAPTER 2 The Quest for Ultra-High Resolution 43
1 introduction 43
2 Imaging Concepts 48
3 TEM, STEM and Diffraction Modes 58
3.1 TEM Mode 58
3.2 STEM Mode 59
3.3 Diffraction Modes 64
4 The Use of Ultra-High Voltages 65
5 The Correction of Aberrations 67
6 Electron Holography 70
6.1 In-Line STEM and TEM Electron Holography 70
6.2 Off-axis Electron Holography 75
7 Combinations of Electron Diffraction and Imaging: Ptychography 79
8 Atomic Focusers 83
9 Discussion 89
References 93
CHAPTER 3 Z-Contrast Imaging in the Scanning Transmission Electron Microscope 97
1 Introduction 97
2 Principles of the Method 100
2.1 Formation of an Incoherent Image 100
2.2 Probe Formation 103
2.3 Incoherent Scattering 105
2.4 Dynamical diffraction 109
3 Advantages of Z-Contrast Imaging 114
3.1 Improved Resolution 114
3.2 Directly Interpretable Image 117
3.3 High Compositional Sensitivity 119
3.4 Simultaneous Conventional HREM Image 122
3.5 Atomic Resolution Spectroscopy 125
4 Problems 127
Appendix: Incoherent Imaging of Weakly Scattering Objects 128
References 129
CHAPTER 4 Inelastic Scattering in Electron Microscopy-Effects, Spectrometry and Imaging 133
1 Inelastic Excitation Processes in Electron Scattering 133
2 Phonon Scattering 137
3 Effects of Inelastic Excitations on Elastic Wave 140
3.1 The Debye-Waller Factor 140
3.2 The Absorption Potential 141
4 Signal from Thermal Diffuse Scattering 141
4.1 Formation of Z-contrast Imaging 141
4.2 The Frozen Lattice Model for Phonon Scattering 144
4.3 Effects on Electron Holography 146
4.4 Effect on Atomic-Resolution Lattice Imaging 149
5 Signal from Plasmon Excitation 152
5.1 Volume Plasmon Excitation 153
5.2 Surface Excitation in Nanoparticles 154
6 Atomic Inner Shell Excitation 157
6.1 Composition Microanalysis 157
6.2 Near Edge Fine Structure and Bonding in Crystals 158
6.3 White Lines and the Occupation Number of the D-Band Electrons 160
6.4 Quantifying Oxygen Deficiency in Oxides 162
7 Energy Filtered Electron Imaging 164
7.1 Composition-Sensitive Imaging Using Valence-Loss Electrons 166
7.2 Composition-Sensitive Imaging Using Inner-Shell Ionization Edges 169
7.3 Mapping the Bonding and Valence State Using Fine Edge Structures 170
8 Dynamic Diffraction Theory of Diffusely Scattered Electrons 173
8.1 The First Order Diffuse Scattering Theory 175
8.2 High Order Diffuse Scattering Theory 176
8.3 What is Missing in Conventional Calculation? 180
9 Summary 182
References 182
CHAPTER 5 Quantitative Analysis of High-Resolution Atomic Image 187
1 Introduction 187
2 Quantitative Geometry Analyses of HREM Images 191
2.1 Atomic Image Segmentation 192
2.2 Methods for Bright Spots Localization in Atomic Image 196
2.3 Lattice Displacement Measurement 198
3 Quantitative Contrast Analysis of HREM Images 199
3.1 R-Factor 199
3.2 Correlation Coefficient 200
3.3 Normalized Euclidean Distance (NED) 200
3.4 Cross-Correlation Factor (XCF) 201
3.5 Normalized Inner Product (NIP) 201
3.6 Normalized Quadratic Difference (NQD) 201
3.7 Normalized Image Cross Correlation Function 201
3.8 Vector Pattern Correlation 202
3.9 X~2-Criterion 202
4 Defect Structure Determination by Quantitative Analysis of Atomic Images 203
4.1 Introduction 203
4.2 Non-Linear Least-Square Algorithm 204
4.3 The X~2 Fitting Algorithm 205
4.4 General Strategies 205
5 Detecting Change of Chemical Composition by Quantitative Atomic Image Analysis 207
5.1 Chemical Lattice Imaging of Materials 207
5.2 Vector Pattern Correlation Method 209
5.3 The De-Convolution and Difference-Convolution Methods 210
5.4 T-C Method 212
5.5 Fourier Coefficient Method 213
5.6 QUANTITEM Method 215
6 Limitation and Future Development 218
References 220
CHAPTER 6 Electron Crystallography-Structure determination by combining HREM, Crystallographic image processing and electron diffraction 223
1 Introduction 223
2 Fundamental Electron Crystallography 225
2.1 Crystal Structure, Crystal Potential and Structure Factors 225
2.2 Crystallographic Structure Factor Phases=Atom Positions 229
3 Solving Crystal Structures from HREM Images by Crystallographic Image Processing 233
3.1 Relation Between HREM Images and the Projected Crystal Potential for Weak-Phase-Objects 234
3.2 Recording and Quantifying HREM Images for Structure Determination 236
3.3 Extracting Crystallographic Amplitudes and Phases 237
3.4 Determining and Compensating for Defocus-and Astigmatism 239
3.5 Determining the Projected Symmetry 243
3.6 Compensating for Crystal Tilt 245
4 Solving Crystal Structures from SAED Patterns by Direct Methods 247
4.1 Introduction to Direct Methods 247
4.2 Recording and Digitizing SAED Patterns for Structure Determination 249
4.3 Application of Direct Methods on Electron Diffraction Data 250
5 Refining Crystal Structures 252
5.1 Introduction to Structure Refinement 252
5.2 Refining Structure Against SAED Intensities 252
5.3 Refining Structure Against X-ray Powder Diffraction Intensities 255
6 3D Electron Crystallography 256
7 Conclusions 257
References 257
CHAPTER 7 Electron Amorphography 261
1 Introduction 261
2 Theoretical Background 264
2.1 Radial Distribution Functions 264
2.2 Debye Formula 266
2.3 Experimental RDFs 267
2.4 Modification Functions 270
3 Examples of Application 272
3.1 Short-Range Order in Aperiodic silicas 273
3.2 First Sharp Diffraction Peak and Medium-Range Order 277
4 Discussion 280
4.1 Partial RDFs 280
4.2 Truncation Effect 281
5 Concluding Remarks 283
References 284
CHAPTER 8 Weak-Beam Electron Microscopy 287
1 Introduction 287
2 Principles of the Weak-Beam Technique 288
2.1 Pendollosung 290
2.2 The Amplitude-Phase Diagram 292
2.3 Weak-Beam Image of a Dislocation 292
2.4 The Coupled-Pendulum as an Analogue of Weak-Beam Imaging 293
2.5 The Amplitude-Phase Diagram for Weak-Beam Imaging 294
3 Practical Weak-Beam Microscopy 298
3.1 Conditions Imposed by Theory 298
3.2 Experimental Procedures 300
4 Applications 302
4.1 Dislocation Dissociation 302
4.2 Determination of stacking Fault Energies 305
4.3 Invisibility Criteria 308
4.4 Weak-Beam Microscopy as the Preferred Tool for Studying Complex Defect Geometries 309
4.5 Stacking Faults 311
4.6 Superlattice Dislocations-a Trap for the Unwary 314
5 Other Weak-Beam Studies 315
6 Conclusions 316
References 316
CHAPTER 9 Point Group and Space Group Identification by Convergent Beam Electron Diffraction 319
1 Introduction 319
1.1 Why Poing Group and Space Group Identification 319
1.2 Why Use CBED 320
1.3 How to Obtain CBED Patterns 321
2 Point Group Identification 324
3 Space Group Identification 335
4 Examples of Point Group and Space Group Identification 343
5 Special Techniques and Other Applications 348
6 Epilogue 349
References 350
CHAPTER 10 Advanced Techniques in TEM Specimen Preparation 353
1 Abstract 353
2 Initial Preparation 355
2.1 Diamond Wheel Sawing 355
2.2 Wire Sawing 357
2.3 Spark Machining 358
3 Prethinning 358
4 Disc Cutting 359
4.1 Discs from Sheet 359
5 Final Thinning 360
5.1 Dimpling 362
5.2 Electropolishing 364
6 Ion Beam Milling 367
6.1 Ion Milling Parameters 368
6.2 Special Preparation Techniques 373
7 Tripod Polishing 376
7.1 Preparation of Specimens 377
7.2 Irregular Specimens 380
8 Small Angle Cleavage Technique 381
8.1 Cleaving Considerations 382
8.2 Preparation of Specimens 384
8.3 Other Applications 388
9 UItramicrotomy 389
10 Direct Preparation Methods 392
11 Focused Ion Beam 394
11.1 The Focused Ion Beam (FIB) Instrument 395
11.2 Conventional FIB TEM Specimen Preparation 397
11.3 The "Lift-Out" Technique 398
11.4 FIB Preparation Tricks of the Trade 399
11.5 Specimen Preparation Induced Damage 400
11.6 Advantages and Disadvantages of the FIB Method 401
11.7 Advances in FIB Instrumentation 402
11.8 Final Comments 402
12 Plasma Cleaning 403
12.1 Background 404
12.2 Plasma Basics 405
12.3 Plasma Processing: Volatilization of Hydrocarbons 407
12.4 Experimental Details 409
12.5 Plasma Conditions and the Effects on the Specimen/Stage 411
13 Conclusion 412
References 412
SUBJECT INDEX 425