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Library | Item Barcode | Call Number | Material Type | Item Category 1 | Status |
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Searching... | 30000010163800 | TK7874.8 D87 2007 | Open Access Book | Book | Searching... |
Searching... | 30000003500489 | TK7874.8 D87 2007 | Open Access Book | Book | Searching... |
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Summary
Summary
This introductory text deals with how electric currents behave at the nanometer scale. The book ties together several aspects of recent research on current flow at the nanoscale, including its relevance in defects, grain boundaries, tunneling, and atomic contacts; its effects through nanostructures, particularly for transistor miniaturization; and the techniques used to probe currents and voltages at the nanoscale, focusing on scanning probe microscopy and transport measurements. It covers topics such as quantum transport, mesoscopic physics, and molecular electronics, among others.Unlike other books on this subject that are almost entirely theoretical, the introductory nature of this book strikes a balance between theory and experiment. Moreover, given the introductory nature of the book, it will not become obsolete quickly and chapters can be added at later stages as new developments inevitably arise. Based largely on MEng and MPhil courses that have been originated and taught by the author, as well as on his own research, the book is written primarily for postgraduate students, but contains elements that undergraduates can also understand and apply. The wide coverage of topics allows for a broad readership base, and serves as a good starting point for those who wish to do work on nanoscale transport.
Table of Contents
Preface | p. vii |
1 Macroscopic Current Flow | p. 1 |
1.1 The Classical (Drude) Model of Electronic Conduction and Ohm's Law | p. 2 |
1.2 The Quantum (Free-Electron) Model of Electronic Conduction | p. 4 |
1.3 The Nearly-Free Electron Model of Electronic Conduction and Band Structure | p. 13 |
1.4 Effective Mass | p. 21 |
1.5 The Origins of Electrical Resistance | p. 24 |
1.6 Size Effects on Electrical Resistance | p. 31 |
1.7 Overview of Transistors | p. 32 |
1.8 Surface Effects | p. 36 |
2 Quantum Current Flow | p. 41 |
2.1 Why Shrink Devices? | p. 44 |
2.2 Point Contacts: From Mesoscopic to Atomic | p. 46 |
2.3 Conductance from Transmission | p. 48 |
2.4 Calculation of Transmission Probability and Current Flow in Quantum Systems | p. 55 |
2.4.1 Introduction to the concept of transmission probability | p. 55 |
2.4.2 Single potential step | p. 57 |
2.4.3 Single potential barrier | p. 61 |
2.4.3.1 Symmetric barrier: No applied voltage | p. 61 |
2.4.3.2 Asymmetric barrier: Current flow due to applied bias | p. 66 |
2.4.4 Double potential barrier | p. 69 |
2.4.4.1 Symmetric barriers: No applied voltage | p. 69 |
2.4.4.2 Tunnelling through multiple barriers with no phase coherence | p. 74 |
2.4.4.3 Asymmetric barriers: Applied voltage | p. 78 |
2.4.4.4 Resonant tunnelling devices: Further details | p. 82 |
2.4.5 A more realistic calculation for a single potential barrier: The WKB approximation | p. 85 |
2.5 Techniques for the Fabrication of Quantum Nanostructures | p. 92 |
3 Mesoscopic Transport: Between the Nanoscale and the Macroscale | p. 99 |
3.1 Introduction | p. 99 |
3.2 Boltzmann Transport Equation | p. 100 |
3.3 Resistivity of Thin Films and Wires: Surface Scattering | p. 100 |
3.3.1 General principles | p. 100 |
3.3.2 1D confinement: Thin film | p. 103 |
3.3.3 2D confinement: Rectangular wire | p. 105 |
3.3.4 2D confinement: Cylindrical wires | p. 106 |
3.4 Resistivity of Thin Films and Wires: Grain-Boundary Scattering | p. 107 |
3.5 Experimental Aspects: How to Measure the Resistance of a Thin Film | p. 113 |
4 Scanning-Probe Multimeters | p. 119 |
4.1 Scanning-Probe Microscopy: An Introduction | p. 119 |
4.2 Scanning Tunnelling Microscopy | p. 121 |
4.2.1 Basic principles | p. 121 |
4.2.2 Scanning tunnelling microscopy in practise | p. 126 |
4.3 Atomic Force Microscopy | p. 134 |
4.3.1 Modes of operation of AFM | p. 135 |
4.3.2 Kelvin-probe force microscopy | p. 140 |
4.3.3 Conducting mode AFM | p. 143 |
5 Electromigration: How Currents Move Atoms, and Implications for Nanoelectronics | p. 155 |
5.1 Introduction to Electromigration, Wire Morphology | p. 155 |
5.2 Fundamentals of Electromigration - The Electron Wind | p. 156 |
5.3 Electromigration-Induced Stress in a Nanowire Device | p. 158 |
5.4 Current-Induced Heating in a Nanowire Device | p. 160 |
5.5 Diffusion of Material, Importance of Surfaces, Failure of Wires | p. 167 |
5.6 Experimental Observations of Electromigration and Heating in Nanowires | p. 169 |
5.6.1 Failure as a function of wire length | p. 170 |
5.6.2 Failure as a function of wire width | p. 170 |
5.7 Experimental Observations of Electromigration in Micron-Scale Wires | p. 173 |
5.8 Wire Heating - Additional Considerations | p. 174 |
5.9 Consequences for Nanoelectronics | p. 181 |
6 Elements of Single-Electron and Molecular Electronics | p. 185 |
6.1 Single-Electron Transport and Coulomb Blockade | p. 185 |
6.2 Molecular Electronics: Why Bother? | p. 188 |
6.3 Mechanisms of Electron Transport Through Molecules | p. 190 |
6.4 Visualising Transport Through Molecules | p. 192 |
6.5 The Contact Resistance Problem | p. 193 |
6.6 Contacting Molecules | p. 194 |
6.6.1 Nanogaps formed by electron-beam lithography | p. 195 |
6.6.2 Nanogaps formed by electromigration | p. 195 |
6.6.3 Mechanically-controlled break junctions | p. 198 |
6.6.4 Molecular sandwiches | p. 200 |
6.6.5 STM probing of molecules | p. 201 |
6.7 The Future | p. 202 |
Solutions to Problems in Chapter 2 | p. 207 |
Index | p. 209 |