Low Voltage Electron Microscopy: Principles and Applications

This timely book delves into the rapidly developing, and cutting–edge field, of low–voltage electron microscopy that has only recently become available due to the rapid developments in the electron optics design and image processing. Low–voltage techniques are particularly crucial in nanotechnology and the study of surface related phenomena, allowing researchers to observe materials as never before. Contributions in this book provide an overview of the different low–voltage microscope techniques for research, essentially providing a handbook for scientists working in this field.  Low Voltage Electron Microscopy:  Principles and Applications focuses on the recent advances in this field, covering topics in TEM, SEM, and STEM, including: New developments in microscope design and improvement in operation. Developments and improvements to existing detector technologies. Novel applications of low voltage for imaging and microanalysis of nanomaterials, biological specimens as well as beam sensitive materials. A discussion dedicated to the unique electron optics designs for SEM and TEM and comparison to the emerging field of He ion microscopy. This topical book highlights the relevant applications of low–voltage microscopy to materials science, nanotechnology and biological research, covering topics such as imaging techniques and elemental microanalysis, and addressing the issues associated with sample preparation requirements for low–voltage imaging and analysis. It will serve as a guide for current and new microscopists and materials scientists who are active in the field of nanotechnology. Edited by two eminently qualified scientists, with contributions from leading researchers, this is the first book in the field to give a description of low voltage electron microscopy as a whole.  

List of Contributors ix Preface xi 1 Introduction to the Theory and Advantages of Low Voltage Electron Microscopy 1 David C. Bell and Natasha Erdman 1.1 Introduction 1 1.2 Historical Perspective 2 1.3 Beam Interaction with Specimen—Elastic and Inelastic Scattering 3 1.4 Instrument Configuration 11 1.5 Influence of Electron Optics Aberrations at Low Voltages 12 1.6 SEM Imaging at Low Voltages 16 1.7 TEM/STEM Imaging and Analysis at Low Voltages 26 1.8 Conclusion 27 References 28 2 SEM Instrumentation Developments for Low kV Imaging and Microanalysis 31 Natasha Erdman and David C. Bell 2.1 Introduction 31 2.2 The Electron Source 33 2.3 SEM Column Design Considerations 36 2.4 Beam Deceleration 41 2.5 Novel Detector Options and Energy Filters 43 2.6 Low Voltage STEM in SEM 48 2.7 Aberration Correction in SEM 50 2.8 Conclusions 53 References 53 3 Extreme High–Resolution (XHR) SEM Using a Beam Monochromator 57 Richard J. Young, Gerard N.A. van Veen, Alexander Henstra and Lubomir Tuma 3.1 Introduction 57 3.2 Limitations in Low Voltage SEM Performance 58 3.3 Beam Monochromator Design and Implementation 59 3.4 XHR Systems and Applications 63 3.5 Conclusions 69 Acknowledgements 70 References 70 4 The Application of Low–Voltage SEM—From Nanotechnology to Biological Research 73 Natasha Erdman and David C. Bell 4.1 Introduction 73 4.2 Specimen Preparation Considerations 74 4.3 Nanomaterials Applications 76 4.4 Beam Sensitive Materials 84 4.5 Semiconductor Materials 85 4.6 Biological Specimens 87 4.7 Low–Voltage Microanalysis 91 4.8 Conclusions 92 References 93 5 Low Voltage High–Resolution Transmission Electron Microscopy 97 David C. Bell 5.1 Introduction 97 5.2 So How Low is Low? 99 5.3 The Effect of Chromatic Aberration and Chromatic Aberration Correction 100 5.4 The Electron Monochromator 103 5.5 Theoretical Tradeoffs of Low kV Imaging 105 5.6 Our Experience at 40 keV LV–HREM 109 5.7 Examples of LV–HREM Imaging 110 5.8 Conclusions 114 References 116 6 Gentle STEM of Single Atoms: Low keV Imaging and Analysis at Ultimate Detection Limits 119 Ondrej L. Krivanek, Wu Zhou, Matthew F. Chisholm, Juan Carlos Idrobo, Tracy C. Lovejoy, Quentin M. Ramasse and Niklas Dellby 6.1 Introduction 119 6.2 Optimizing STEM Resolution and Probe Current at Low Primary Energies 121 6.3 STEM Image Formation 128 6.4 Gentle STEM Applications 135 6.5 Discussion 154 6.6 Conclusion 156 Acknowledgements 157 References 157 7 Low Voltage Scanning Transmission Electron Microscopy of Oxide Interfaces 163 Robert Klie 7.1 Introduction 163 7.2 Methods and Instrumentation 166 7.3 Low Voltage Imaging and Spectroscopy 168 7.4 Summary 180 Acknowledgements 180 References 180 8 What’s Next? The Future Directions in Low Voltage Electron Microscopy 185 David C. Bell and Natasha Erdman 8.1 Introduction 185 8.2 Unique Low Voltage SEM and TEM Instruments 186 8.3 Cameras, Detectors, and Other Accessories 192 8.4 Conclusions 198 References 199 Index 201