Introduction to Nanoelectronic Single-Electron Circuit Design

Jaap Hoekstra

• Publisher: Jenny Stanford Publishing
• Year: 2016
• Print ISBN: 9789814745567
• eBook ISBN: 9781315340814
• Edition: 2
• Topic: Physical Sciences
• Subtopic: Biology

Today, the concepts of single-electron tunneling (SET) are used to understand and model single-atom and single-molecule nanoelectronics. The characteristics of nanoelectronic devices, especially SET transistors, can be understood on the basis of the physics of nanoelectronic devices and circuit models. A circuit theory approach is necessary for considering possible integration with current microelectronic circuitry. To explain the properties and possibilities of SET devices, this book follows an approach to modeling these devices using electronic circuit theory. All models and equivalent circuits are derived from the first principles of circuit theory. Based on energy conservation, the circuit model of SET is an impulsive current source, and modeling distinguishes between bounded and unbounded currents. The Coulomb blockade is explained as a property of a single junction. In addition, this edition differs from the previous one by elaborating on the section on spice simulations and providing a spice simulation on the SET electron box circuit, including the spice netlist. Also, a complete, new proof of the two-capacitor problem in circuit theory is presented; the importance of this proof in understanding energy conservation in SET circuits cannot be underestimated. This book will be very useful for advanced undergraduate- and graduate-level students of electrical engineering and nanoelectronics and researchers in nanotechnology, nanoelectronic device physics, and computer science.

Only book modeling both single-electron tunneling and many electron tunneling from the points of view of electronics; starting from experiments, via a physics description, working towards a circuit description; and based on energy conservation, in electrical circuits, developing the impulse circuit model for single-electron tunneling.

Chapter 1

Introduction

In this chapter the topic of nanoelectronics is introduced and a bird’s eye view is presented to familiarize the reader with the kind of possibilities and challenges this book is dealing with. Successively, the general scope, electron tunneling, tunneling capacitors, island charges, bounded and unbounded currents, and energy in simple capacitor circuits are introduced briefly.

Introduction to Nanoelectronic Single-Electron Circuit Design (2nd Edition)

Jaap Hoekstra

Copyright © 2016 Pan Stanford Publishing Pte. Ltd.

ISBN 978-981-4745-56-7 (Hardcover), 978-981-4745-57-4 (eBook)

www.panstanford.com

1.1 Scope

Due to the ongoing downsizing of microelectronic circuit components, many nanoelectronic devices have been proposed and manufactured in the past years. These nanoelectronic devices have critical dimensions of several nanometers and take advantage of quantum mechanical phenomena that appear at the nanometer scale.

Using these criteria, the tunnel diode or Esaki diode (Section 2.1) can be seen as the first nanoelectronic device. Its operation differs from the diffusion of electrons and holes across the potential barrier in ordinary p–n junctions in that electrons also tunnel through the potential barrier because the barrier of the tunnel diode is extremely narrow.

Another nanoelectronic device is formed when a capacitor is scaled down. If the insulating layer is thin enough, again, tunneling of electrons through the dielectric from the negative to the positive side may occur (Section 5.3). Consequently, not only a displacement current but also a conductive tunnel current can flow through the capacitor. Combining both currents, the nanoelectronic capacitor may be described as a tunnel diode parallel to a normal capacitor in the first instance. The model is a suitable circuit model when we consider currents; the modeling in this case is sometimes called macromodeling.

For individual electrons, however, the model is not correct. Due to the quantization of charge, tunneling of single electrons can be observed. Chapter 2 deals with experiments showing the effects of tunneling of single electrons: Coulomb blockade and Coulomb oscillations. To include the possible tunneling of single electrons the model of the capacitor and the parallel tunnel diode cannot be used; instead of this a circuit model is developed depending on the elementary charge of the electron.

Because of the capacitor part in the equivalent circuit models, basic capacitor circuits are discussed throughout the text. Special attention is paid to the energy balance in those circuits. It will turn out that this issue is of great importance to both the equivalent circuit of the tunneling capacitor and the condition for tunneling of single electrons.

1.1.1 Nanoelectronic Circuit Design Issues

To understand the possible utilization of nanoelectronic devices, useful and competitive circuits have to be designed. New circuit ideas must be developed, exploiting the quantum character, the small feature size, and the low-power operation of new nanoelectronic devices.

There are a couple of different definitions of nanoelectronics around today. From the physics point of view, nanoelectronics often deals with small circuits, including nanoelectronic devices in whi...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Contents
• Preface
• Preface to the Second Edition
• 1 Introduction
• 2 Tunneling Experiments in Nanoelectronics
• 3 Current in Electrodynamics and Circuit Theory
• 4 Free Electrons in Quantum Mechanics
• 5 Current and Tunnel Current in Quantum Physics
• 6 Energy in Circuit Theory
• 7 Energy in the Switched Two-Capacitor Circuit
• 8 Impulse Circuit Model for Single-Electron Tunneling: Zero Tunneling Time
• 9 Impulse Circuit Model for Single-Electron Tunneling: Nonzero Tunneling Times
• 10 Generalizing the Theory to Multijunction Circuits
• 11 Single-Electron Tunneling Circuit Examples
• 12 Circuit Design Methodologies
• 13 More Potential Applications and Challenges
• Epilogue to the First Edition
• References
• Index