Physical Principles of Electron Microscopy: An Introduction to TEM ...

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Analytical Electron Microscopy 175 Figure 6-10. Electron energy-loss spectrum of a high-temperature superconductor, showing N- and M-shell ionization edges of barium, the K-ionization edge of oxygen, and weak ionization edges from copper and yttrium. The plasmon peak represents inelastic scattering from valence electrons. A logarithmic vertical scale has been used in order to accommodate the large range of electron intensity. Courtesy of D.H. Shin (Ph.D. thesis, Cornell University).
Chapter 7 RECENT DEVELOPMENTS 7.1 Scanning Transmission Electron Microscopy In Section 1.6, we noted that a field-emission STEM was the first instrument to successfully image single atoms in the late 1960’s. Several years later, a “dedicated STEM” (operating only in scanning mode) was manufactured by the Vacuum Generators Company in the UK. A cross-sectional diagram of a substantially modified version of this instrument (at IBM Watson Research Laboratories) is shown in Fig. 7-1. Because there is no need for a viewing screen inside the lens column, its electron gun is located at the bottom of the instrument (with some advantage in terms of mechanical stability) and the electron detectors are on top (making it easier to modify the detectors or add new ones). Most STEM images are recorded in dark-field mode, using an annular dark-field (ADF) detector located just above the specimen. Its design is similar to that of a Robinson or solid-state BSE detector used in the SEM (Fig. 5-10) but it collects electrons that are transmitted through the specimen and scattered within a certain angular range (�min to �max), determined by the inner and outer diameters. By making �min large, only large-angle (mainly elastic) scattering is collected. According to Eq. (4.15), its intensity is proportional to Z 2 . Therefore the ADF image contains strong atomic-number contrast and not much diffraction contrast (most of the diffracted electrons have a scattering angle less than �min and pass through the central hole in the detector). Although the signal is weak, the annular detector design provides high collection efficiency, as all azimuthal angles of scattering are recorded (unlike the case of dark-field imaging in a conventional TEM).
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Ray F. Egerton Physical Principles
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To Maia
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viii Contents 3.3 Condenser-Lens Sy
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PREFACE The telescope transformed o
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Chapter 1 AN INTRODUCTION TO MICROS
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An Introduction to Microscopy 3 In
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An Introduction to Microscopy 23 A
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28 Chapter 2 Rule 1 states that for
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30 Chapter 2 that is curved rather
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32 Chapter 2 x 0 object principal p
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34 Chapter 2 2.3. Imaging with Elec
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36 Chapter 2 cross-product or vecto
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38 Chapter 2 important to remember
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40 Chapter 2 A cross section throug
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42 Chapter 2 As an example, we can
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44 Chapter 2 microscopes, at a time
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46 Chapter 2 When these non-paraxia
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48 Chapter 2 So far, we have said n
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50 Chapter 2 from the lens) for ele
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52 Chapter 2 P (a) P (b) y y x x +V
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54 Chapter 2 The stigmators found i
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Chapter 3 THE TRANSMISSION ELECTRON
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The Transmission Electron Microscop
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Chapter 4 TEM SPECIMENS AND IMAGES
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TEM Specimens and Images 95 v 0 m M
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TEM Specimens and Images 97 In prac
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TEM Specimens and Images 99 P e (>
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TEM Specimens and Images 101 4.4 Sc
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TEM Specimens and Images 103 Figure
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TEM Specimens and Images 107 dimens
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TEM Specimens and Images 109 (discu
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TEM Specimens and Images 111 Figure
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TEM Specimens and Images 117 underf
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TEM Specimens and Images 119 From t
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TEM Specimens and Images 121 (a) (b
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Page 163 and 164: 156 Chapter 6 where h = 6.63 � 10
Page 165 and 166: 158 Chapter 6 Many-electron atoms r
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Page 171 and 172: 164 Chapter 6 Ideally, each peak in
Page 173 and 174: 166 Chapter 6 to balance the units
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Page 179 and 180: 172 Chapter 6 different from the co
Page 181: 174 Chapter 6 A typical energy-loss
Page 185 and 186: Recent Developments 179 Figure 7-2.
Page 187 and 188: Recent Developments 181 below 0.1 n
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Page 191 and 192: Recent Developments 185 Besides hav
Page 193 and 194: Recent Developments 187 Figure 7-7.
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Page 197 and 198: 192 Appendix cathode vacuum + + + +
Page 199 and 200: 194 Appendix The variable � repre
Page 201 and 202: 196 References Neutze, R., Wouts, R
Page 203 and 204: 198 Index Bright-field image, 100 B
Page 205 and 206: 200 Index Inner-shell ionization, 1
Page 207: 202 Index Stacking fault, 114 Stage
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