Nanotechnology by Poole and Owens PDF

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INTRODUCTION TO NANOTECHNOLOGY Charles P. Poole, Jr. Frank J. Owens @z+::iCIENcE zyxwvutsrqponmlkjihgfe A JOHN WILEY 81 SONS, INC., PUBLICATION Copyright Q 2003 by John Wiley & Sons, Inc. All rights reserved Published by John Wiley & Sons, Inc., Hoboken, New Jersey. Published simultaneously...

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INTRODUCTION TO NANOTECHNOLOGY

Charles P. Poole, Jr. Frank J. Owens

@z+::iCIENcE A JOHN WILEY 81 SONS, INC., PUBLICATION

Copyright Q 2003 by John Wiley & Sons, Inc. All rights reserved Published by John Wiley & Sons, Inc., Hoboken, New Jersey. Published simultaneously in Canada. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning, or otherwise, except as permitted under Section 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, Inc.. 222 Rosewood Drive, Danvers, MA 01923. 978-750-8400, fax 978-750-4470, or on the web at www.copyright.com. Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 11 1 River Street, Hoboken, NJ 07030, (201) 748-601 1, fax (201) 748-6008, e-mail: [email protected]. Limit of Liability/Disclaimer of Warranty: While the publisher and author have used their best efforts in preparing this book, they make no representations or warranties with respect to the accuracy or completeness of the contents of this book and specifically disclaim any implied warranties of merchantability or fitness for a particular purpose. No warranty may be created or extended by sales representatives or written sales materials. The advice and strategies contained herein may not be suitable for your situation. You should consult with a professional where appropriate. Neither the publisher nor author shall be liable for any loss of profit or any other commercial damages, including but not limited to special, incidental, consequential, or other damages. For general information on our other products and services please contact our Customer Care Department within the US. at 877-762-2974, outside the US. at 3 17-572-3993 or fax 317-572-4002. Wiley also publishes its books in a variety of electronic formats. Some content that appears in print, however, may not be available in electronic format.

Library of Congress Cataloging-in-PublicationData: Poole, Charles P Introduction to nanotechnology/Charles P Poole, Jr., Frank J. Owens. p.cm. “A Wiley-Interscience publication.” Includes bibliographical references and index. ISBN 0-471 -07935-9 (cloth) 1. Nanotechnology. I. Owens, Frank J. 11. Title T174.7. P66 2003 620.54~21 Printed in the United States of America 10 9 8 7 6 5

2002191031

CONTENTS xi

Preface 1 Introduction 2

Introduction to Physics of the Solid State 2.1

Structure 8 2.1.1 Size Dependence of Properties 8 2.1.2 Crystal Structures 9 2.1.3 Face-Centered Cubic Nanoparticles 12 2.1.4 Tetrahedrally Bonded Semiconductor Structures 15 2.1.5 Lattice Vibrations 18

2.2

Energy Bands 20 2.2.1 Insulators, Semiconductors, and Conductors 20 2.2.2 Reciprocal Space 22 2.2.3 Energy Bonds and Gaps of Semiconductors 23 2.2.4 Effective Masses 28 2.2.5 Fermi Surfaces 29

2.3

Localized Particles 30 2.3.1 Donors, Acceptors, and Deep Traps 30 2.3.2 Mobility 31 2.3.3 Excitons 32

3 Methods of Measuring Properties

1

8

35

3.1 Introduction 35 3.2

Structure 36 3.2.1 Atomic Structures 36 3.2.2 Crystallography 37 V

Vi

CONTENTS

3.2.3 Particle Size Determination 42 3.2.4 Surface Structure 45 3.3

Microscopy 46 3.3.1 Transmission Electron Microscopy 46 3.3.2 Field Ion Microscopy 51 3.3.3 Scanning Microscopy 51

3.4 Spectroscopy 58 3.4.1 Infrared and Raman Spectroscopy 58 3.4.2 Photoemission and X-Ray Spectroscopy 62 3.4.3 Magnetic Resonance 68 4

Properties of Individual Nanoparticles

72

4.1 Introduction 72 4.2 Metal 4.2.1 4.2.2 4.2.3 4.2.4 4.2.5 4.2.6 4.2.7 4.2.8

Nanoclusters 74 Magic Numbers 74 Theoretical Modeling of Nanoparticles 75 Geometric Structure 78 Electronic Structure 81 Reactivity 83 Fluctuations 86 Magnetic Clusters 86 Bulk to Nanotransition 88

4.3

Semiconducting Nanoparticles 90 4.3.1 Optical Properties 90 4.3.2 Photofkagmentation 92 4.3.3 Coulombic Explosion 93

4.4

Rare Gas and Molecular Clusters 94 4.4.1 Inert-Gas Clusters 94 4.4.2 Superfluid Clusters 95 4.4.3 Molecular Clusters 96

4.5

Methods of Synthesis 97 4.5.1 RF Plasma 97 4.5.2 Chemical Methods 98 4.5.3 Thermolysis 99 4.5.4 Pulsed Laser Methods 100

4.6

Conclusion 101

5 Carbon Nanostructures 5.1 Introduction 103

103

CONTENTS

Vii

5.2 Carbon Molecules 103 5.2.1 Nature of the Carbon Bond 103 5.2.2 New Carbon Structures 105 5.3 Carbon Clusters 106 5.3.1 Small Carbon Clusters 106 5.3.2 Discovery of c60 107 5.3.3 Structure of c 6 0 and Its Crystal 110 5.3.4 Alkali-Doped c 6 0 110 5.3.5 Superconductivity in c60 112 5.3.6 Larger and Smaller Fullerenes 113 5.3.7 Other Buckyballs 113 5.4 Carbon Nanotubes 114 5.4.1 Fabrication 114 5.4.2 Structure 117 5.4.3 Electrical Properties 118 5.4.4 Vibrational Properties 122 5.4.5 Mechanical Properties 123 5.5 Applications of Carbon Nanotubes 125 5.5.1 Field Emission and Shielding 125 5.5.2 Computers 126 5.5.3 Fuel Cells 127 5.5.4 Chemical Sensors 128 5.5.5 Catalysis 129 5.5.6 Mechanical Reinforcement 130 6

Bulk Nanostructured Materials 6.1 Solid Disordered Nanostructures 133 6.1.1 Methods of Synthesis 133 6.1.2 Failure Mechanisms of Conventional Grain-Sized Materials 137 6.1.3 Mechanical Properties 139 6.1.4 Nanostructured Multilayers 141 6.1.5 Electrical Properties 142 6.1.6 Other Properties 147 6.1.7 Metal Nanocluster Composite Glasses 148 6.1.8 Porous Silicon 150 6.2 Nanostructured Crystals 153 6.2.1 Natural Nanocrystals 153 6.2.2 Computational Prediction of Cluster Lattices 153 6.2.3 Arrays of Nanoparticles in Zeolites 154 6.2.4 Crystals of Metal Nanoparticles 157

133

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CONTENTS

6.2.5 Nanoparticle Lattices in Colloidal Suspensions 158 6.2.6 Photonic Crystals 159

7 Nanostructured Ferromagnetism

165

7.1 Basics of Ferromagnetism 165 7.2

Effect of Bulk Nanostructuring of Magnetic Properties 170

7.3 Dynamics of Nanomagnets 172 7.4 Nanopore Containment of Magnetic Particles 176 7.5 Nanocarbon Ferromagnets 177 7.6

Giant and Colossal Magnetoresistance 181

7.7 Ferrofluids 186

8 Optical and Vibrational Spectroscopy

194

8.1 Introduction 194 8.2 Infrared Frequency Range 196 8.2.1 Spectroscopy of Semiconductors; Excitons 196 8.2.2 Infrared Surface Spectroscopy 198 8.2.3 Raman Spectroscopy 203 8.2.4 Brillouin Spectroscopy 210 8.3 Luminescence 213 8.3.1 Photoluminescence 213 8.3.2 Surface States 215 8.3.3 Thermoluminescence 221 8.4 Nanostructures in Zeolite Cages 222

9 Quantum Wells, Wires, and Dots 9.1 Introduction 226 9.2 Preparation of Quantum Nanostructures 227 9.3

Size and Dimensionality Effects 231 9.3.1 Size Effects 231 9.3.2 Conduction Electrons and Dimensionality 233 9.3.3 Fermi Gas and Density of States 234 9.3.4 Potential Wells 236 9.3.5 Partial Confinement 241 9.3.6 Properties Dependent on Density of States 242

226

CONTENTS

9.4

Excitons 244

9.5

Single-Electron Tunneling 245

9.6

Applications 248 9.6.1 Infrared Detectors 248 9.6.2 Quantum Dot Lasers 251

9.7

Superconductivity 253

10 Self-Assembly and Catalysis 10.1

iX

257

Self-Assembly 257 10.1.1 Process of Self-Assembly 257 10.1.2 Semiconductor Islands 258 10.1.3 Monolayers 260

10.2 Catalysis 264 10.2.1 Nature of Catalysis 264 10.2.2 Surface Area of Nanoparticles 264 10.2.3 Porous Materials 268 10.2.4 Pillared Clays 273 10.2.5 Colloids 277

11 Organic Compounds and Polymers

11.1 Introduction 28 1 11.2 Forming and Characterizing Polymers 283 11.2.1 Polymerization 283 11.2.2 Sizes of Polymers 284 11.3 Nanocrystals 285 11.3.1 Condensed Ring Types 285 11.3.2 Polydiacetylene Types 289 11.4 Polymers 292 11.4.1 Conductive Polymers 292 1 1.4.2 Block Copolymers 293 11.5 Supramolecular Structures 295 11.5.1 Transition-Metal-Mediated Types 295 11.5.2 Dendritic Molecules 296 11.5.3 Supramolecular Dendrimers 302 11.5.4 Micelles 305

281

X

CONTENTS

12 Biological Materials

310

12.1 Introduction 3 10 12.2 Biological Building Blocks 3 1 1 12.2.1 Sizes of Building Blocks and Nanostructures 3 11 12.2.2 Polypeptide Nanowire and Protein Nanoparticle 3 14 12.3 Nucleic Acids 3 16 12.3.1 DNA Double Nanowire 316 12.3.2 Genetic Code and Protein Synthesis 322 12.4 Biological Nanostructures 324 12.4.1 Examples of Proteins 324 12.4.2 Micelles and Vesicles 326 12.4.3 Multilayer Films 329

13 Nanomachines and Nanodevices

332

13.1 Microelectromechanical Systems (MEMSs) 332 13.2 Nanoelectromechanical Systems (NEMSs) 335 13.2.1 Fabrication 335 13.2.2 Nanodevices and Nanomachines 339 13.3 Molecular and Supramolecular Switches 345

A

Formulas for Dimensionality

357

A. 1 Introduction 357 A.2 Delocalization 357 A.3

Partial Confinement 358

B Tabulations of Semiconducting Material Properties

Index

361

371

PREFACE

In recent years nanotechnology has become one of the most important and exciting forefront fields in Physics, Chemistry, Engineering and Biology. It shows great promise for providing us in the near future with many breakthroughs that will change the direction of technological advances in a wide range of applications. To facilitate the timely widespread utilization of this new technology it is important to have available an overall summary and commentary on this subject which is sufficiently detailed to provide a broad coverage and insight into the area, and at the same time is sufficiently readable and thorough so that it can reach a wide audience of those who have a need to know the nature and prospects for the field. The present book hopes to achieve these two aims. The current widespread interest in nanotechnology dates back to the years 1996 to 1998 when a panel under the auspices of the World Technology Evaluation Center (WTEC), funded by the National Science Foundation and other federal agencies, undertook a world-wide study of research and development in the area of nanotechnology, with the purpose of assessing its potential for technological innovation. Nanotechnology is based on the recognition that particles less than the size of 100 nanometers (a nanometer is a billionth of a meter) impart to nanostructures built from them new properties and behavior. This happens because particles which are smaller than the characteristic lengths associated with particular phenomena often display new chemistry and physics, leading to new behavior which depends on the size. So, for example, the electronic structure, conductivity, reactivity, melting temperature, and mechanical properties have all been observed to change when particles become smaller than a critical size. The dependence of the behavior on the particle sizes can allow one to engineer their properties. The WTEC study concluded that this technology has enormous potential to contribute to significant advances over a wide and diverse range of technological areas ranging from producing stronger and lighter materials, to shortening the delivery time of nano structured pharmaceuticals to the body’s circulatory system, increasing the storage capacity of magnetic tapes, and providing faster switches for computers. Recommendations made by this and subsequent panels have led to the appropriation of very high levels of finding in recent years. The research area of nanotechnology is interdisciplinary, xi

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PREFACE

covering a wide variety of subjects ranging from the chemistry of the catalysis of nanoparticles, to the physics of the quantum dot laser. As a result researchers in any one particular area need to reach beyond their expertise in order to appreciate the broader implications of nanotechnology, and learn how to contribute to this exciting new field. Technical managers, evaluators, and those who must make funding decisions will need to understand a wide variety of disciplines. Although this book was originally intended to be an introduction to nanotechnology, due to the nature of the field it has developed into an introduction to selected topics in nanotechnology, which are thought to be representative of the overall field. Because of the rapid pace of development of the subject, and its interdisciplinary nature, a truly comprehensive coverage does not seem feasible. The topics presented here were chosen based on the maturity of understanding of the subjects, their potential for applications, or the number of already existing applications. Many of the chapters discuss present and future possibilities. General references are included for those who wish to pursue fiuther some of the areas in which this technology is moving ahead. We have attempted to provide an introduction to the subject of nanotechnology written at a level such that researchers in different areas can obtain an appreciation of developments outside their present areas of expertise, and so that technical administrators and managers can obtain an overview of the subject. It is possible that such a book could be used as a text for a graduate course on nanotechnology. Many of the chapters contain introductions to the basic physical and chemical principles of the subject area under discussion, hence the various chapters are self contained, and may be read independently of each other. Thus Chapter 2 begins with a brief overview of the properties of bulk materials that need to be understood if one is to appreciate how, and why, changes occur in these materials when their sizes approach a billionth of a meter. An important impetus that caused nanotechnology to advance so rapidly has been the development of instrumentation such as the scanning tunneling microscope that allows the visualization of the surfaces of nanometer sized materials. Hence Chapter 3 presents descriptions of important instrumentation systems, and provides illustrations of measurements on nano materials. The remaining chapters cover various aspects of the field. One of us (CPP) would like to thank his son Michael for drawing several dozen of the figures that appear throughout the book, and his grandson Jude Jackson for helping with several of these figures. We appreciate the comments of Prof. Austin Hughes on the biology chapter. We have greatly benefited from the information found in the five volume Handbook of Nanostructured Materials and Nanotechnology edited by H. S. Nalwa, and in the book Advanced Catalysis and Nanostructured Materials edited by W. R. Moser, both from Academic Press.

INTRODUCTION

The prefix nano in the word nanotechnology means a billionth (1 x lop9). Nanotechnology deals with various structures of matter having dimensions of the order of a billionth of a meter. While the word nanotechnology is relatively new, the existence of functional devices and structures of nanometer dimensions is not new, and in fact such structures have existed on Earth as long as life itself. The abalone, a mollusk, constructs very strong shells having iridescent inner surfaces by organizing calcium carbonate into strong nanostructured bricks held together by a glue made of a carbohydrate-protein mix. Cracks initiated on the outside are unable to move through the shell because of the nanostructured bricks. The shells represent a natural demonstration that a structure fabricated from nanoparticles can be much stronger. We will discuss how and why nanostructuring leads to stronger materials in Chapter 6. It is not clear when humans first began to take advantage of nanosized materials. It is known that in the fourth-century A.D. Roman glassmakers were fabricating glasses containing nanosized metals. An artifact from this period called the Lycurgus cup resides in the British Museum in London. The cup, which depicts the death of King Lycurgus, is made from soda lime glass containing sliver and gold nanoparticles. The color of the cup changes from green to a deep red when a light source is placed inside it. The great varieties of beautiful colors of the windows of medieval cathedrals are due to the presence of metal nanoparticles in the glass.

Introduction to Nunotechnology, by Charles P. Poole Jr. and Frank J. Owens. ISBN 0471-07935-9. Copyright 0 2003 John Wiley & Sons, Inc.

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INTRODUCTION

The potential importance of clusters was recognized by the Irish-born chemist Robert Boyle in his Sceptical Chyrnist published in 1661. In it Boyle criticizes Aristotle’s belief that matter is composed of four elements: earth, fire, water, and air. Instead, he suggests that tiny particles of matter combine in various ways to form what he calls corpuscles. He refers to “minute masses or clusters that were not easily dissipable into such particles that composed them.” Photography is an advanced and mature technology, developed in the eighteenth and nineteenth centuries, which depends on production of silver nanoparticles sensitive to light. Photographic film is an emulsion, a thin layer of gelatin containing silver halides, such as silver bromide, and a base of transparent cellulose acetate. The light decomposes the silver halides, producing nanoparticles of silver, which are the pixels of the image. In the late eighteenth century the British scientists Thomas Wedgewood and Sir Humprey Davy were able to produce images using silver nitrate and chloride, but their images were not permanent. A number of French and British researchers worked on the problem in the nineteenth century. Such names as Daguerre, Niecpce, Talbot, Archer, and Kennet were involved. Interestingly James Clark Maxwell, whose major contributions were to electromagnetic theory, produced the first color photograph in 1861. Around 1883 the American inventor George Eastman, who would later found the Kodak Corporation, produced a film consisting of a long paper strip coated with an emulsion containing silver halides. He later developed this into a flexible film that could be rolled, which made photography accessible to many. So technology based on nanosized materials is really not that new. In 1857 Michael Faraday published a paper in the Philosophical Transactions of the Royal SocieQ, which attempted to explain how metal particles affect the color of church windows. Gustav Mie was the first to provide an explanation of the dependence of the color of the glasses on metal size and kind. His paper was published in the German Journal Annalen der Physik (Leipzig) in 1908. Richard Feynman was awarded the Nobel Prize in physics in 1965 for his contributions to quantum electrodynamics, a subject far removed from nanotechnology. Feynman was also a very gifted and flamboyant teacher and lecturer on science, and is regarded as one of the great theoretical physicists of his time. He had a wide range of interests beyond science from playing bongo drums to attempting to interpret Mayan hieroglyphics. The range of his interests and wit can be appreciated by reading his lighthearted autobiographical book Surely You ’re Joking, Mr. Fqnman. In 1960 he presented a visionary and prophetic lecture at a meeting of the American Physical Society, entitled “There is Plenty of Room at the Bottom,” where he speculated on the possibility and potential of nanosized materials. He envisioned etching lines a few atoms wide with beams of electrons, effectively predicting the existence of electron-beam lithography, which is u...