Current at the nanoscale : an introduction to nanoelectronics / Colm Durkan.

Format:

Book

Author/Creator:

Durkan, Colm.

Language:

English

Subjects (All):

Nanoelectronics.

Physical Description:

xii, 211 pages : illustrations ; 24 cm

Place of Publication:

London : Imperial College Press ; Hackensack, NJ : Distributed by World Scientific Pub., [2007]

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.

Contents:

1 Macroscopic Current Flow 1

1.1 The Classical (Drude) Model of Electronic Conduction and Ohm's Law 2

1.2 The Quantum (Free-Electron) Model of Electronic Conduction 4

1.3 The Nearly-Free Electron Model of Electronic Conduction and Band Structure 13

1.4 Effective Mass 21

1.5 The Origins of Electrical Resistance 24

1.6 Size Effects on Electrical Resistance 31

1.7 Overview of Transistors 32

1.8 Surface Effects 36

2 Quantum Current Flow 41

2.1 Why Shrink Devices? 44

2.2 Point Contacts: From Mesoscopic to Atomic 46

2.3 Conductance from Transmission 48

2.4 Calculation of Transmission Probability and Current Flow in Quantum Systems 55

2.4.1 Introduction to the concept of transmission probability 55

2.4.2 Single potential step 57

2.4.3 Single potential barrier 61

2.4.3.1 Symmetric barrier: No applied voltage 61

2.4.3.2 Asymmetric barrier: Current flow due to applied bias 66

2.4.4 Double potential barrier 69

2.4.4.1 Symmetric barriers: No applied voltage 69

2.4.4.2 Tunnelling through multiple barriers with no phase coherence 74

2.4.4.3 Asymmetric barriers: Applied voltage 78

2.4.4.4 Resonant tunnelling devices: Further details 82

2.4.5 A more realistic calculation for a single potential barrier: The WKB approximation 85

2.5 Techniques for the Fabrication of Quantum Nanostructures 92

3 Mesoscopic Transport: Between the Nanoscale and the Macroscale 99

3.2 Boltzmann Transport Equation 100

3.3 Resistivity of Thin Films and Wires: Surface Scattering 100

3.3.2 1D confinement: Thin film 103

3.3.3 2D confinement: Rectangular wire 105

3.3.4 2D confinement: Cylindrical wires 106

3.4 Resistivity of Thin Films and Wires: Grain-Boundary Scattering 107

3.5 Experimental Aspects: How to Measure the Resistance of a Thin Film 113

4 Scanning-Probe Multimeters 119

4.1 Scanning-Probe Microscopy: An Introduction 119

4.2 Scanning Tunnelling Microscopy 121

4.2.2 Scanning tunnelling microscopy in practise 126

4.3 Atomic Force Microscopy 134

4.3.1 Modes of operation of AFM 135

4.3.2 Kelvin-probe force microscopy 140

4.3.3 Conducting mode AFM 143

5 Electromigration: How Currents Move Atoms, and Implications for Nanoelectronics 155

5.1 Introduction to Electromigration, Wire Morphology 155

5.2 Fundamentals of Electromigration - The Electron Wind 156

5.3 Electromigration-Induced Stress in a Nanowire Device 158

5.4 Current-Induced Heating in a Nanowire Device 160

5.5 Diffusion of Material, Importance of Surfaces, Failure of Wires 167

5.6 Experimental Observations of Electromigration and Heating in Nanowires 169

5.6.1 Failure as a function of wire length 170

5.6.2 Failure as a function of wire width 170

5.7 Experimental Observations of Electromigration in Micron-Scale Wires 173

5.8 Wire Heating - Additional Considerations 174

5.9 Consequences for Nanoelectronics 181

6 Elements of Single-Electron and Molecular Electronics 185

6.1 Single-Electron Transport and Coulomb Blockade 185

6.2 Molecular Electronics: Why Bother? 188

6.3 Mechanisms of Electron Transport Through Molecules 190

6.4 Visualising Transport Through Molecules 192

6.5 The Contact Resistance Problem 193

6.6 Contacting Molecules 194

6.6.1 Nanogaps formed by electron-beam lithography 195

6.6.2 Nanogaps formed by electromigration 195

6.6.3 Mechanically-controlled break junctions 198

6.6.4 Molecular sandwiches 200

6.6.5 STM probing of molecules 201

6.7 The Future 202.

Notes:

Includes bibliographical references and index.

ISBN:

9781860948237

1860948235

OCLC:

171560859