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Handbook of nanoscience, engineering technology

Handbook of

NANOSCIENCE,
ENGINEERING,
and TECHNOLOGY


Handbook of

NANOSCIENCE,
ENGINEERING,
and TECHNOLOGY
Edited by

William A. Goddard, III
California Institute of Technology
The Beckman Institute
Pasadena, California

Donald W. Brenner
North Carolina State University

Raleigh, North Carolina

Sergey Edward Lyshevski
Rochester Institute of Technology
Rochester, New York

Gerald J. Iafrate
North Carolina State University
Raleigh, North Carolina

CRC PR E S S
Boca Raton London New York Washington, D.C.


The front cover depicts a model of a gramicidin ionic channel showing the atoms forming the protein, and the conduction
pore defined by a representative potential isosurface. The back cover (left) shows a 3D simulation of a nano-arch termination/
zipping of a graphite crystal edge whose structure may serve as an element for a future nanodevice, and as a template for
nanotube growth. The back cover (right) shows five figures explained within the text.
Cover design by Benjamin Grosser, Imaging Technology Group, Beckman Institute for Advanced Science and Technology,
University of Illinois at Urbana-Champaign. Ionic channel image (front) by Grosser and Janet Sinn-Hanlon; data by Munoj
Gupta and Karl Hess. Graphite nano-arch simulation image (back left) by Grosser and Slava V. Rotkin; data by Rotkin.
Small figure images by (from top to bottom): 1) T. van der Straaten; 2) Rotkin and Grosser; 3) Rotkin and Grosser; 4) B.
Tuttle, Rotkin and Grosser; 5) Rotkin and M. Dequesnes. Background image by Glenn Fried.

Library of Congress Cataloging-in-Publication Data
Handbook of nanoscience, engineering, and technology / edited by William A. Goddard,
III … [et al.].
p. cm. — (Electrical engineering handbook series)
Includes bibliographical references and index.
ISBN 0-8493-1200-0 (alk. paper)
1. Molecular electronics. 2. Nanotechnology. I. Goddard, William A., 1937– II. Series.
TK7874.8 .H35 2002
620′.5—dc21

2002073329

This book contains information obtained from authentic and highly regarded sources. Reprinted material is quoted with
permission, and sources are indicated. A wide variety of references are listed. Reasonable efforts have been made to publish
reliable data and information, but the authors and the publisher cannot assume responsibility for the validity of all materials
or for the consequences of their use.


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Visit the CRC Press Web site at www.crcpress.com
© 2003 by CRC Press LLC
No claim to original U.S. Government works
International Standard Book Number 0-8493-1200-0
Library of Congress Card Number 2002073329
Printed in the United States of America 1 2 3 4 5 6 7 8 9 0
Printed on acid-free paper


Dedication

For my wife Karen, for her dedication and love, and for Sophie and Maxwell.
Donald W. Brenner

For my dearest wife Marina, and for my children Lydia and Alexander.
Sergey E. Lyshevski

To my wife, Kathy, and my family for their loving support and patience.
Gerald J. Iafrate

© 2003 by CRC Press LLC


Preface

In the now-famous talk given in 1959, “There’s Plenty of Room at the Bottom,” Nobel Prize laureate
Richard Feynman outlined the promise of nanotechnology. It took over two decades, but the development
of the scanning tunneling microscope by IBM researchers in the early 1980s gave scientists and engineers
the ability not only to image atoms but also to manipulate atoms and clusters with a precision equal to
that of a chemical bond. Also in the 1980s, Eric Drexler wrote several books that went beyond Feynman’s
vision to outline a fantastic technology that includes pumps, gears, and molecular assemblers consisting
of only hundreds to thousands of atoms that, if built, promised to revolutionize almost every aspect of
human endeavor. While Drexler’s vision continues to stir controversy and skepticism in the science
community, it has served to inspire a curious young generation to pursue what is perceived as the next
frontier of technological innovation. Fueled by breakthroughs such as in the production and characterization of fullerene nanotubes, self-assembled monolayers, and quantum dots — together with advances
in theory and modeling and concerted funding from the National Nanotechnology Initiative in the U.S.
and similar programs in other countries — the promise of nanotechnology is beginning to come true.
Will nanotechnology revolutionize the human condition? Only time will tell. Clearly, though, this is an
exciting era in which to be involved in science and engineering at the nanometer scale.
Research at the nanometer scale and the new technologies being developed from this research are
evolving much too rapidly for a book like this to provide a complete picture of the field. Many journals
such as Nature, Science, and Physical Review Letters report critical breakthroughs in nanometer-scale
science and technology almost weekly. Instead, the intent of this handbook is to provide a wide-angle
snapshot of the state of the field today, including basic concepts, current challenges, and advanced research
results, as well as a glimpse of the many breakthroughs that will assuredly come in the next decade and
beyond. Specifically, visionary research and developments in nanoscale and molecular electronics, biotechnology, carbon nanotubes, and nanocomputers are reported. This handbook is intended for a wide
audience, with chapters that can be understood by laymen and educate and challenge seasoned researchers. A major goal of this handbook is to further develop and promote nanotechnology by expanding its
horizon to new and exciting areas and fields in engineering, science, medicine, and technology.

© 2003 by CRC Press LLC


Acknowledgments

Dr. Brenner would like to thank his current and former colleagues for their intellectual stimulation and
personal support. Especially thanked are Dr. Brett Dunlap, Professor Barbara Garrison, Professor Judith
Harrison, Professor John Mintmire, Professor Rod Ruoff, Dr. Peter Schmidt, Professor Olga Shenderova,
Professor Susan Sinnott, Dr. Deepak Srivastava, and Dr. Carter White. Professor Brenner also wishes to
thank the Office of Naval Research, the National Science Foundation, the NASA Ames and NASA Langley
Research Centers, the Army Research Office, and the Department of Energy for supporting his research
group over the last 8 years.
Donald W. Brenner
This handbook is the product of the collaborative efforts of all contributors. Correspondingly, I would
like to acknowledge the authors’ willingness, commitment, and support of this timely project. The support
and assistance I have received from the outstanding CRC team, lead by Nora Konopka, Helena Redshaw,
and Gail Renard, are truly appreciated and deeply treasured. In advance, I would like also to thank the
readers who will provide feedback on this handbook.
Sergey Edward Lyshevski
I would like to acknowledge the career support and encouragement from my colleagues, the Department
of Defense, the University of Notre Dame, and North Carolina State University.
Gerald J. Iafrate

© 2003 by CRC Press LLC


About the Editors

William A. Goddard, III, obtained his Ph.D. in Engineering Science
(minor in Physics) from the California Institute of Technology,
Pasadena, in October 1964, after which he joined the faculty of the
Chemistry Department at Caltech and became a professor of theoretical chemistry in 1975.
In November 1984, Goddard was honored as the first holder of the
Charles and Mary Ferkel Chair in Chemistry and Applied Physics.
He received the Badger Teaching Prize from the Chemistry and
Chemical Engineering Division for Fall 1995.
Goddard is a member of the National Academy of Sciences (U.S.)
and the International Academy of Quantum Molecular Science. He
was a National Science Foundation (NSF) Predoctoral Fellow
(1960–1964) and an Alfred P. Sloan Foundation Fellow (1967–69).
In 1978 he received the Buck–Whitney Medal (for major contributions to theoretical chemistry in North America). In 1988 he received
the American Chemical Society Award for Computers in Chemistry.
In 1999 he received the Feynman Prize for Nanotechnology Theory (shared with Tahir Cagin and Yue
Qi). In 2000 he received a NASA Space Sciences Award (shared with N. Vaidehi, A. Jain, and G. Rodriquez).
He is a fellow of the American Physical Society and of the American Association for the Advancement
of Science. He is also a member of the American Chemical Society, the California Society, the California
Catalysis Society (president for 1997–1998), the Materials Research Society, and the American Vacuum
Society. He is a member of Tau Beta Pi and Sigma Xi.
His activities include serving as a member of the board of trustees of the Gordon Research Conferences (1988–1994), the Computer Science and Telecommunications Board of the National Research
Council (1990–1993), and the Board on Chemical Science and Technology (1980s), and a member
and chairman of the board of advisors for the Chemistry Division of the NSF (1980s). In addition,
Goddard serves or has served on the editorial boards of several journals ( Journal of the American
Chemical Society, Journal of Physical Chemistry, Chemical Physics, Catalysis Letters, Langmuir, and
Computational Materials Science).
Goddard is director of the Materials and Process Simulation Center (MSC) of the Beckman Institute
at Caltech. He was the principal investigator of an NSF Grand Challenge Application Group
(1992–1997) for developing advanced methods for quantum mechanics and molecular dynamics
simulations optimized for massively parallel computers. He was also the principal investigator for the
NSF Materials Research Group at Caltech (1985–1991).
Goddard is a co-founder (1984) of Molecular Simulations Inc., which develops and markets stateof-the-art computer software for molecular dynamics simulations and interactive graphics for

© 2003 by CRC Press LLC


applications to chemistry, biological, and materials sciences. He is also a co-founder (1991) of
Schrödinger, Inc., which develops and markets state-of-the-art computer software using quantum
mechanical methods for applications to chemical, biological, and materials sciences. In 1998 he cofounded Materials Research Source LLC, dedicated to development of new processing techniques
for materials with an emphasis on nanoscale processing of semiconductors. In 2000 he co-founded
BionomiX Inc., dedicated to predicting the structures and functions of all molecules for all known
gene sequences.
Goddard’s research activities focus on the use of quantum mechanics and of molecular dynamics
to study reaction mechanisms in catalysis (homogeneous and heterogeneous); the chemical and electronic properties of surfaces (semiconductors, metals, ceramics, and polymers); biochemical processes;
the structural, mechanical, and thermodynamic properties of materials (semiconductors, metals,
ceramics, and polymers); mesoscale dynamics; and materials processing. He has published over 440
scientific articles.
Donald W. Brenner is currently an associate professor in the
Department of Materials Science and Engineering at North Carolina State University. He earned his B.S. from the State University
of New York College at Fredonia in 1982 and his Ph.D. from
Pennsylvania State University in 1987, both in chemistry. He
joined the Theoretical Chemistry Section at the U.S. Naval
Research Laboratory as a staff scientist in 1987 and the North
Carolina State University faculty in 1994. His research interests
focus on using atomic and mesoscale simulation and theory to
understand technologically important processes and materials.
Recent research areas include first-principles predictions of the
mechanical properties of polycrystalline ceramics; crack dynamics;
dynamics of nanotribology, tribochemistry, and nanoindentation;
simulation of the vapor deposition and surface reactivity of covalent materials; fullerene-based materials and devices; self-assembled monolayers; simulations of shock and detonation chemistry; and potential function
development. He is also involved in the development of new cost-effective virtual reality technologies
for engineering education.
Brenner’s awards include the Alcoa Foundation Engineering Research Achievement Award (2000),
the Veridian Medal Paper (co-author, 1999), an Outstanding Teacher Award from the North Carolina
State College of Engineering (1999), an NSF Faculty Early Career Development Award (1995), the
Naval Research Laboratory Chemistry Division Young Investigator Award (1991), the Naval Research
Laboratory Chemistry Division Berman Award for Technical Publication (1990), and the Xerox Award
from Penn State for the best materials-related Ph.D. thesis (1987). He was the scientific co-chair for
the Eighth (2000) and Ninth (2001) Foresight Conferences on Molecular Nanotechnology; and he is
a member of the editorial board for the journal Molecular Simulation, the Scientific Advisory Boards
of Nanotechnology Partners and of L.P. and Apex Nanotechnologies, and the North Carolina State
University Academy of Outstanding Teachers.

© 2003 by CRC Press LLC


Sergey Edward Lyshevski earned his M.S. (1980) and Ph.D. (1987)
degrees from Kiev Polytechnic Institute, both in electrical engineering. From 1980 to 1993 Dr. Lyshevski held faculty positions at the
Department of Electrical Engineering at Kiev Polytechnic Institute
and the Academy of Sciences of Ukraine. From 1989 to 1993 he was
head of the Microelectronic and Electromechanical Systems Division
at the Academy of Sciences of Ukraine. From 1993 to 2002, he was
with Purdue University/Indianapolis. In 2002, Dr. Lyshevski joined
Rochester Institute of Technology, where he is a professor of electrical
engineering.
Lyshevski serves as the senior faculty fellow at the U.S. Surface and
Undersea Naval Warfare Centers. He is the author of eight books including Nano- and Micro-Electromechanical Systems: Fundamentals of Micro- and Nano- Engineering (for which he also acts as CRC series
editor; CRC Press, 2000); MEMS and NEMS: Systems, Devices, and Structures (CRC Press, 2002); and
author or co-author of more than 250 journal articles, handbook chapters, and regular conference papers.
His current teaching and research activities are in the areas of MEMS and NEMS (CAD, design, highfidelity modeling, data-intensive analysis, heterogeneous simulation, fabrication), intelligent large-scale
microsystems, learning configurations, novel architectures, self-organization, micro- and nanoscale
devices (actuators, sensors, logics, switches, memories, etc.), nanocomputers and their components,
reconfigurable (adaptive) defect-tolerant computer architectures, and systems informatics. Dr. Lyshevski
has been active in the design, application, verification, and implementation of advanced aerospace,
automotive, electromechanical, and naval systems.
Lyshevski has made 29 invited presentations (nationally and internationally) and has taught undergraduate and graduate courses in NEMS, MEMS, microsystems, computer architecture, motion devices,
integrated circuits, and signals and systems.
Gerald J. Iafrate joined the faculty of North Carolina State University
in August 2001. Previously, he was a professor at the University of
Notre Dame; he also served as Associate Dean for Research in the
College of Engineering, and as director of the newly established
University Center of Excellence in Nanoscience and Technology. He
has extensive experience in managing large interdisciplinary research
programs. From 1989 to 1997, Dr. Iafrate served as the Director of
the U.S. Army Research Office (ARO). As director, he was the Army’s
key executive for the conduct of extramural research in the physical
and engineering sciences in response to DoD-wide objectives. Prior
to becoming Director of ARO, Dr. Iafrate was the Director of Electronic Devices Research at the U.S. Army Electronics Technology and
Devices Laboratory (ETDL). Working with the National Science
Foundation, he played a key leadership role in establishing the firstof-its-kind Army–NSF–University consortium.
He is currently a professor of electrical and computer engineering at North Carolina State University,
Raleigh, where his research interests include quantum transport in nanostructures such as resonant
tunneling diodes and quantum dots. He is also conducting studies in the area of quantum dissipation,
with emphasis on ratchet-like transport phenomena and nonequilibrium processes in nanosystems. Dr.
Iafrate is a fellow of the IEEE, APS, and AAAS.

© 2003 by CRC Press LLC


Contributors

S. Adiga

Kwong–Kit Choi

J.A. Harrison

North Carolina State University
Department of Materials Science
and Engineering
Raleigh, NC

U.S. Army Research Laboratory
Adelphi, MD

U.S. Naval Academy
Chemistry Department
Annapolis, MD

Damian G. Allis
Syracuse University
Department of Chemistry
Syracuse, NY

Narayan R. Aluru
University of Illinois
Beckman Institute for Advanced
Science and Technology
Urbana, IL

D.A. Areshkin
North Carolina State University
Department of Materials Science
and Engineering
Raleigh, NC

Rashid Bashir
Purdue University
School of Electrical and
Computer Engineering
Department of Biomedical
Engineering
West Lafayette, IN

Donald W. Brenner
North Carolina State University
Department of Materials Science
and Engineering
Raleigh, NC

© 2003 by CRC Press LLC

Almadena Y.
Chtchelkanova

Scott A. Henderson

Strategic Analysis, Inc.
Arlington, VA

Starpharma Limited
Melbourne, Victoria, Australia

Supriyo Datta

Karl Hess

Purdue University
School of Electrical and
Computer Engineering
West Lafayette, IN

University of Illinois
Beckman Institute for Advanced
Science and Technology
Urbana, IL

James C. Ellenbogen

G. Holan

The MITRE Corporation
Nanosystems Group
McLean, VA

Starpharma Limited
Melbourne, Victoria, Australia

Michael Pycraft Hughes
R. Esfand
Central Michigan University
Dendritic Nanotechnologies Ltd.
Mt. Pleasant, MI

University of Surrey
School of Engineering
Guildford, Surrey, England

Dustin K. James
Michael Falvo
University of North Carolina
Department of Physics and
Astronomy
Chapel Hill, NC

Richard P. Feynman
California Institute of Technology
Pasadena, CA

Rice University
Department of Chemistry
Houston, TX

Jean-Pierre Leburton
University of Illinois
Beckman Institute for Advanced
Science and Technology
Urbana, IL


Wing Kam Liu

Airat A. Nazarov

Umberto Ravaioli

Northwestern University
Department of Mechanical
Engineering
Evanston, IL

Russian Academy of Science
Institute for Metals
Superplasticity Problems
Ufa, Russia

University of Illinois
Beckman Institute for Advanced
Science and Technology
Urbana, IL

J. Christopher Love

Gregory N. Parsons

Slava V. Rotkin

Harvard University
Cambridge, MA

Sergey Edward
Lyshevski
Rochester Institute of
Technology
Department of Electrical
Engineering
Rochester, NY

North Carolina State University
Department of Chemical
Engineering
Raleigh, NC

University of Illinois
Beckman Institute for Advanced
Science and Technology
Urbana, IL

Magnus Paulsson

Rodney S. Ruoff

Purdue University
School of Electrical and
Computer Engineering
West Lafayette, IN

Karen Mardel
Starpharma Limited
Melbourne, Victoria, Australia

William McMahon
University of Illinois
Beckman Institute for Advanced
Science and Technology
Urbana, IL

Meyya Meyyappan
NASA Ames Research Center
Moffett Field, CA

Vladimiro Mujica
Northwestern University
Department of Chemistry
Evanston, IL

Wolfgang Porod
University of Notre Dame
Department of Electrical
Engineering
Notre Dame, IN

Dennis W. Prather
University of Delaware
Department of Electrical and
Computer Engineering
Newark, DE

Dong Qian
Northwestern University
Department of Mechanical
Engineering
Evanston, IL

© 2003 by CRC Press LLC

J.D. Schall
North Carolina State University
Department of Materials Science
and Engineering
Raleigh, NC

Ahmed S. Sharkawy
University of Delaware
Department of Electrical and
Computer Engineering
Newark, DE

O.A. Shenderova
North Carolina State University
Department of Materials Science
and Engineering
Raleigh, NC

Shouyuan Shi

Radik R. Mulyukov
Russian Academy of Science
Institute for Metals
Superplasticity Problems
Ufa, Russia

Northwestern University
Department of Mechanical
Engineering
Evanston, IL

Mark A. Ratner
Northwestern University
Department of Chemistry
Evanston, IL

University of Delaware
Department of Electrical and
Computer Engineering
Newark, DE


James T. Spencer

Donald A. Tomalia

Sean Washburn

Syracuse University
Department of Chemistry
Syracuse, NY

Central Michigan University
Dendritic Nanotechnologies Ltd.
Mt. Pleasant, MI

University of North Carolina
Department of Physics and
Astronomy
Chapel Hill, NC

Deepak Srivastava

James M. Tour

NASA Ames Research Center
Moffett Field, CA

Rice University
Center for Nanoscale Science
and Technology
Houston, TX

Martin Staedele
Infineon Technologies AG
Corporate Research ND
Munich, Germany

Richard Superfine
University of North Carolina
Department of Physics and
Astronomy
Chapel Hill, NC

Russell M. Taylor, II
University of North Carolina
Department of Computer
Science, Physics, and
Astronomy
Chapel Hill, NC

© 2003 by CRC Press LLC

DARPA/DSO, NRL
Arlington, VA

Boris I. Yakobson
Daryl Treger
Strategic Analysis, Inc.
Arlington, VA

S.J. Stuart
Clemson University
Department of Chemistry
Clemson, SC

Stuart A. Wolf

Rice University
Center for Nanoscale Science
and Technology
Houston, TX

Blair R. Tuttle
Pennsylvania State University
Behrend College
School of Science
Erie, PA

Min–Feng Yu
University of Illinois
Department of Mechanical and
Industrial Engineering
Urbana, IL

Trudy van der Straaten
University of Illinois
Beckman Institute for Advanced
Science and Technology
Urbana, IL

Gregory J. Wagner
Northwestern University
Department of Mechanical
Engineering
Evanston, IL

Ferdows Zahid
Purdue University
School of Electrical and
Computer Engineering
West Lafayette, IN


Contents

Section 1 The Promise of Nanotechnology and Nanoscience

1

There’s Plenty of Room at the Bottom: An Invitation to Enter a New
Field of Physics Richard P. Feynman
1.1

2

Transcript

Room at the Bottom, Plenty of Tyranny at the Top
2.1
2.2
2.3
2.4
2.5

Karl Hess

Rising to the Feynman Challenge
Tyranny at the Top
New Forms of Switching and Storage
New Architectures
How Does Nature Do It?

Section 2 Molecular and Nano-Electronics: Concepts,
Challenges, and Designs

3

Engineering Challenges in Molecular Electronics

4

Molecular Electronic Computing Architectures

Gregory N. Parsons

Abstract
3.1 Introduction
3.2 Silicon-Based Electrical Devices and Logic Circuits
3.3 CMOS Device Parameters and Scaling
3.4 Memory Devices
3.5 Opportunities and Challenges for Molecular Circuits
3.6 Summary and Conclusions
Acknowledgments
References

4.1
4.2
4.3

James M. Tour
and Dustin K. James
Present Microelectronic Technology
Fundamental Physical Limitations of Present Technology
Molecular Electronics

© 2003 by CRC Press LLC


4.4 Computer Architectures Based on Molecular Electronics
4.5 Characterization of Switches and Complex Molecular Devices
4.6 Conclusion
Acknowledgments
References

5

Nanoelectronic Circuit Architectures

6

Nanocomputer Architectronics and Nanotechnology

7

Architectures for Molecular Electronic Computers

Wolfgang Porod

Abstract
5.1 Introduction
5.2 Quantum-Dot Cellular Automata (QCA)
5.3 Single-Electron Circuits
5.4 Molecular Circuits
5.5 Summary
Acknowledgments
References

Sergey Edward Lyshevski
Abstract
6.1 Introduction
6.2 Brief History of Computers: Retrospects and Prospects
6.3 Nanocomputer Architecture and Nanocomputer Architectronics
6.4 Nanocomputer Architectronics and Neuroscience
6.5 Nanocomputer Architecture
6.6 Hierarchical Finite-State Machines and Their Use in Hardware and Software Design
6.7 Adaptive (Reconfigurable) Defect-Tolerant Nanocomputer Architectures,
Redundancy, and Robust Synthesis
6.8 Information Theory, Entropy Analysis, and Optimization
6.9 Some Problems in Nanocomputer Hardware–Software Modeling
References

James C. Ellenbogen
and J. Christopher Love
Abstract
7.1 Introduction
7.2 Background
7.3 Approach and Objectives
7.4 Polyphenylene-Based Molecular Rectifying Diode Switches: Design and
Theoretical Characterization
7.5 Novel Designs for Diode-Based Molecular Electronic Digital Circuits
7.6 Discussion
7.7 Summary and Conclusions
Acknowledgments

© 2003 by CRC Press LLC


References
Appendix 7.A
Appendix 7.B
Appendix 7.C

8

Spintronics — Spin-Based Electronics

9

QWIP: A Quantum Device Success

Stuart A. Wolf, Almadena Y. Chtchelkanova,
and Daryl Treger
Abstract
8.1 Spin Transport Electronics in Metallic Systems
8.2 Issues in Spin Electronics
8.3 Potential Spintronics Devices
8.4 Quantum Computation and Spintronics
8.5 Conclusion
Acknowledgments
References

Kwong-Kit Choi
Abstract
9.1 Introduction
9.2 QWIP Focal Plane Array Technology
9.3 Optical Properties of Semiconductor Nanostructures
9.4 Transport Properties of Semiconductor Nanostructures
9.5 Noise in Semiconductor Nanostructures
9.6 Voltage-Tunable QWIPs
9.7 Quantum Grid Infrared Photodetectors
9.8 Conclusion
Acknowledgments
References

Section 3 Molecular Electronics: Fundamental Processes

10

Molecular Conductance Junctions: A Theory and Modeling
Progress Report Vladimiro Mujica and Mark A. Ratner
Abstract
10.1 Introduction
10.2 Experimental Techniques for Molecular Junction Transport
10.3 Coherent Transport: The Generalized Landauer Formula
10.4 Gating and Control of Junctions: Diodes and Triodes
10.5 The Onset of Inelasticity
10.6 Molecular Junction Conductance and Nonadiabatic Electron Transfer
10.7 Onset of Incoherence and Hopping Transport

© 2003 by CRC Press LLC


10.8 Advanced Theoretical Challenges
10.9 Remarks
Acknowledgments
References

11

Modeling Electronics at the Nanoscale

12

Resistance of a Molecule

Narayan R. Aluru, Jean-Pierre Leburton,
William McMahon, Umberto Ravaioli, Slava V. Rotkin, Martin Staedele, Trudy van der
Straaten, Blair R. Tuttle, and Karl Hess
11.1 Introduction
11.2 Nanostructure Studies of the Si-SiO2 Interface
11.3 Modeling of Quantum Dots and Artificial Atoms
11.4 Carbon Nanotubes and Nanotechnology
11.5 Simulation of Ionic Channels
11.6 Conclusions
Acknowledgments
References

Magnus Paulsson, Ferdows Zahid, and Supriyo Datta
12.1 Introduction
12.2 Qualitative Discussion
12.3 Coulomb Blockade?
12.4 Nonequilibrium Green’s Function (NEGF) Formalism
12.5 An Example: Quantum Point Contact (QPC)
12.6 Concluding Remarks
Acknowledgments
12.A MATLAB® Codes
References

Section 4 Manipulation and Assembly

13

Nanomanipulation: Buckling, Transport, and Rolling at the Nanoscale
Richard Superfine, Michael Falvo, Russell M. Taylor, II, and Sean Washburn
13.1 Introduction
13.2 Instrumentation Systems: The Nanomanipulator and Combined Microscopy Tools
13.3 Nanomanipulation for Mechanical Properties
13.4 Conclusion
Acknowledgments
References

© 2003 by CRC Press LLC


14

Nanoparticle Manipulation by Electrostatic Forces

15

Biologically Mediated Assembly of Artificial Nanostructures
and Microstructures Rashid Bashir

Michael Pycraft Hughes

14.1 Introduction
14.2 Theoretical Aspects of AC Electrokinetics
14.3 Applications of Dielectrophoresis on the Nanoscale
14.4 Limitations of Nanoscale Dielectrophoresis
14.5 Conclusion
References

Abstract
15.1 Introduction
15.2 Bio-Inspired Self-Assembly
15.3 The Forces and Interactions of Self-Assembly
15.4 Biological Linkers
15.5 State of the Art in Bio-Inspired Self-Assembly
15.6 Future Directions
15.7 Conclusions
Acknowledgments
References

16

Nanostructural Architectures from Molecular Building Blocks
Damian G. Allis and James T. Spencer
16.1 Introduction
16.2 Bonding and Connectivity
16.3 Molecular Building Block Approaches
References

Section 5 Functional Structures and Mechanics

17

Nanomechanics

Boris I. Yakobson
Abstract
17.1 Introduction
17.2 Linear Elastic Properties
17.3 Nonlinear Elasticity and Shell Model
17.4 Atomic Relaxation and Failure Mechanisms
17.5 Kinetic Theory of Strength
17.6 Coalescence of Nanotubes as a Reversed Failure
17.7 Persistence Length, Coils, and Random FuzzBalls of CNTS

© 2003 by CRC Press LLC


Acknowledgments
References

18

Carbon Nanotubes

19

Mechanics of Carbon Nanotubes

20

Dendrimers — An Enabling Synthetic Science to Controlled Organic
Nanostructures Donald A. Tomalia, Karen Mardel, Scott A. Henderson, G. Holan, and

Meyya Meyyappan and Deepak Srivastava
18.1 Introduction
18.2 Structure and Properties of Carbon Nanotubes
18.3 Computational Modeling and Simulation
18.4 Nanotube Growth
18.5 Material Development
18.6 Application Development
18.7 Concluding Remarks
Acknowledgments
References
Dong Qian, Gregory J. Wagner, Wing Kam Liu,
Min-Feng Yu, and Rodney S. Ruoff
Abstract
19.1 Introduction
19.2 Mechanical Properties of Nanotubes
19.3 Experimental Techniques
19.4 Simulation Methods
19.5 Mechanical Applications of Nanotubes
19.6 Conclusions
Acknowledgments
References

R. Esfand
Introduction
The Dendritic State
Unique Dendrimer Properties
Dendrimers as Nanopharmaceuticals and Nanomedical Devices
Dendrimers as Reactive Modules for the Synthesis of More Complex Nanoscale
Architectures
20.6 Conclusions
Acknowledgments
References
20.1
20.2
20.3
20.4
20.5

21

Design and Applications of Photonic Crystals

Dennis W. Prather,
Ahmed S. Sharkawy, and Shouyuan Shi
21.1 Introduction
21.2 Photonic Crystals — How They Work
21.3 Analogy between Photonic and Semiconductor Crystals

© 2003 by CRC Press LLC


21.4 Analyzing Photonic Bandgap Structures
21.5 Electromagnetic Localization in Photonic Crystals
21.6 Doping of Photonic Crystals
21.7 Microcavities in Photonic Crystals
21.8 Photonic Crystal Applications
References

22

Nanostructured Materials

23

Nano- and Micromachines in NEMS and MEMS

24

Contributions of Molecular Modeling to Nanometer-Scale Science and
Technology Donald W. Brenner, O.A. Shenderova, J.D. Schall, D.A. Areshkin, S. Adiga,

Airat A. Nazarov and Radik R. Mulyukov
22.1 Introduction
22.2 Preparation of Nanostructured Materials
22.3 Structure
22.4 Properties
22.5 Concluding Remarks
Acknowledgments
References
Sergey Edward Lyshevski
Abstract
23.1 Introduction to Nano- and Micromachines
23.2 Biomimetics and Its Application to Nano- and Micromachines: Directions
toward Nanoarchitectronics
23.3 Controlled Nano- and Micromachines
23.4 Synthesis of Nano- and Micromachines: Synthesis and Classification Solver
23.5 Fabrication Aspects
23.6 Introduction to Modeling and Computer-Aided Design: Preliminaries
23.7 High-Fidelity Mathematical Modeling of Nano- and Micromachines:
Energy-Based Quantum and Classical Mechanics and Electromagnetics
23.8 Density Functional Theory
23.9 Electromagnetics and Quantization
23.10 Conclusions
References

J.A. Harrison, and S.J. Stuart
Opening Remarks
24.1 Molecular Simulations
24.2 First-Principles Approaches: Forces on the Fly
24.3 Applications
24.4 Concluding Remarks
Acknowledgments
References

© 2003 by CRC Press LLC


1

There’s Plenty of Room
at the Bottom: An
Invitation to Enter a
New Field of Physics
CONTENTS
1.1

Richard P. Feynman
California Institute of Technology

Transcript
How Do We Write Small? • Information on a Small Scale •
Better Electron Microscopes • The Marvelous Biological
System • Miniaturizing the Computer • Miniaturization by
Evaporation • Problems of Lubrication • A Hundred Tiny
Hands • Rearranging the Atoms • Atoms in a Small World •
High School Competition

This transcript of the classic talk that Richard Feynman gave on December 29, 1959, at the annual meeting
of the American Physical Society at the California Institute of Technology (Caltech) was first published
in the February 1960 issue (Volume XXIII, No. 5, pp. 22–36) of Caltech’s Engineering and Science, which
owns the copyright. It has been made available on the web at http://www.zyvex.com/nanotech/feynman.html with their kind permission.
For an account of the talk and how people reacted to it, see Chapter 4 of Nano! by Ed Regis. An
excellent technical introduction to nanotechnology is Nanosystems: Molecular Machinery, Manufacturing,
and Computation by K. Eric Drexler.

1.1 Transcript
I imagine experimental physicists must often look with envy at men like Kamerlingh Onnes, who
discovered a field like low temperature, which seems to be bottomless and in which one can go down
and down. Such a man is then a leader and has some temporary monopoly in a scientific adventure.
Percy Bridgman, in designing a way to obtain higher pressures, opened up another new field and was
able to move into it and to lead us all along. The development of ever-higher vacuum was a continuing
development of the same kind.
I would like to describe a field in which little has been done but in which an enormous amount can
be done in principle. This field is not quite the same as the others in that it will not tell us much of
fundamental physics (in the sense of “what are the strange particles?”); but it is more like solid-state
physics in the sense that it might tell us much of great interest about the strange phenomena that occur
in complex situations. Furthermore, a point that is most important is that it would have an enormous
number of technical applications.

© 2003 by CRC Press LLC


1-2

Handbook of Nanoscience, Engineering, and Technology

What I want to talk about is the problem of manipulating and controlling things on a small scale.
As soon as I mention this, people tell me about miniaturization, and how far it has progressed today.
They tell me about electric motors that are the size of the nail on your small finger. And there is a device
on the market, they tell me, by which you can write the Lord’s Prayer on the head of a pin. But that’s
nothing; that’s the most primitive, halting step in the direction I intend to discuss. It is a staggeringly
small world that is below. In the year 2000, when they look back at this age, they will wonder why it was
not until the year 1960 that anybody began seriously to move in this direction.
Why cannot we write the entire 24 volumes of the Encyclopaedia Britannica on the head of a pin?
Let’s see what would be involved. The head of a pin is a sixteenth of an inch across. If you magnify it by
25,000 diameters, the area of the head of the pin is then equal to the area of all the pages of the Encyclopaedia
Britannica. Therefore, all it is necessary to do is to reduce in size all the writing in the encyclopedia by
25,000 times. Is that possible? The resolving power of the eye is about 1/120 of an inch — that is roughly
the diameter of one of the little dots on the fine half-tone reproductions in the encyclopedia. This, when
you demagnify it by 25,000 times, is still 80 angstroms in diameter — 32 atoms across, in an ordinary metal.
In other words, one of those dots still would contain in its area 1000 atoms. So, each dot can easily be
adjusted in size as required by the photoengraving, and there is no question that there is enough room on
the head of a pin to put all of the Encyclopaedia Britannica. Furthermore, it can be read if it is so written.
Let’s imagine that it is written in raised letters of metal; that is, where the black is in the encyclopedia, we
have raised letters of metal that are actually 1/25,000 of their ordinary size. How would we read it?
If we had something written in such a way, we could read it using techniques in common use today.
(They will undoubtedly find a better way when we do actually have it written, but to make my point
conservatively I shall just take techniques we know today.) We would press the metal into a plastic
material and make a mold of it, then peel the plastic off very carefully, evaporate silica into the plastic
to get a very thin film, then shadow it by evaporating gold at an angle against the silica so that all the
little letters will appear clearly, dissolve the plastic away from the silica film, and then look through it
with an electron microscope!
There is no question that if the thing were reduced by 25,000 times in the form of raised letters on
the pin, it would be easy for us to read it today. Furthermore, there is no question that we would find it
easy to make copies of the master; we would just need to press the same metal plate again into plastic
and we would have another copy.

How Do We Write Small?
The next question is, how do we write it? We have no standard technique to do this now. But let me
argue that it is not as difficult as it first appears to be. We can reverse the lenses of the electron microscope
in order to demagnify as well as magnify. A source of ions, sent through the microscope lenses in reverse,
could be focused to a very small spot. We could write with that spot like we write in a TV cathode ray
oscilloscope, by going across in lines and having an adjustment that determines the amount of material
which is going to be deposited as we scan in lines.
This method might be very slow because of space charge limitations. There will be more rapid methods.
We could first make, perhaps by some photo process, a screen that has holes in it in the form of the
letters. Then we would strike an arc behind the holes and draw metallic ions through the holes; then we
could again use our system of lenses and make a small image in the form of ions, which would deposit
the metal on the pin.
A simpler way might be this (though I am not sure it would work): we take light and, through an
optical microscope running backwards, we focus it onto a very small photoelectric screen. Then electrons
come away from the screen where the light is shining. These electrons are focused down in size by the
electron microscope lenses to impinge directly upon the surface of the metal. Will such a beam etch away
the metal if it is run long enough? I don’t know. If it doesn’t work for a metal surface, it must be possible
to find some surface with which to coat the original pin so that, where the electrons bombard, a change
is made which we could recognize later.

© 2003 by CRC Press LLC


There’s Plenty of Room at the Bottom: An Invitation to Enter a New Field of Physics

1-3

There is no intensity problem in these devices — not what you are used to in magnification, where
you have to take a few electrons and spread them over a bigger and bigger screen; it is just the opposite.
The light which we get from a page is concentrated onto a very small area so it is very intense. The few
electrons which come from the photoelectric screen are demagnified down to a very tiny area so that,
again, they are very intense. I don’t know why this hasn’t been done yet!
That’s the Encyclopedia Britannica on the head of a pin, but let’s consider all the books in the world.
The Library of Congress has approximately 9 million volumes; the British Museum Library has 5 million
volumes; there are also 5 million volumes in the National Library in France. Undoubtedly there are
duplications, so let us say that there are some 24 million volumes of interest in the world.
What would happen if I print all this down at the scale we have been discussing? How much space
would it take? It would take, of course, the area of about a million pinheads because, instead of there
being just the 24 volumes of the encyclopedia, there are 24 million volumes. The million pinheads can
be put in a square of a thousand pins on a side, or an area of about 3 square yards. That is to say, the
silica replica with the paper-thin backing of plastic, with which we have made the copies, with all this
information, is on an area approximately the size of 35 pages of the encyclopedia. That is about half
as many pages as there are in this magazine. All of the information which all of mankind has ever
recorded in books can be carried around in a pamphlet in your hand — and not written in code, but
a simple reproduction of the original pictures, engravings, and everything else on a small scale without
loss of resolution.
What would our librarian at Caltech say, as she runs all over from one building to another, if I tell
her that, 10 years from now, all of the information that she is struggling to keep track of — 120,000
volumes, stacked from the floor to the ceiling, drawers full of cards, storage rooms full of the older books
— can be kept on just one library card! When the University of Brazil, for example, finds that their
library is burned, we can send them a copy of every book in our library by striking off a copy from the
master plate in a few hours and mailing it in an envelope no bigger or heavier than any other ordinary
airmail letter. Now, the name of this talk is “There Is Plenty of Room at the Bottom” — not just “There
Is Room at the Bottom.” What I have demonstrated is that there is room — that you can decrease the
size of things in a practical way. I now want to show that there is plenty of room. I will not now discuss
how we are going to do it, but only what is possible in principle — in other words, what is possible
according to the laws of physics. I am not inventing antigravity, which is possible someday only if the
laws are not what we think. I am telling you what could be done if the laws are what we think; we are
not doing it simply because we haven’t yet gotten around to it.

Information on a Small Scale
Suppose that, instead of trying to reproduce the pictures and all the information directly in its present
form, we write only the information content in a code of dots and dashes, or something like that, to
represent the various letters. Each letter represents six or seven “bits” of information; that is, you need
only about six or seven dots or dashes for each letter. Now, instead of writing everything, as I did before,
on the surface of the head of a pin, I am going to use the interior of the material as well.
Let us represent a dot by a small spot of one metal, the next dash by an adjacent spot of another metal,
and so on. Suppose, to be conservative, that a bit of information is going to require a little cube of atoms
5 × 5 × 5 — that is 125 atoms. Perhaps we need a hundred and some odd atoms to make sure that the
information is not lost through diffusion or through some other process.
I have estimated how many letters there are in the encyclopedia, and I have assumed that each of my
24 million books is as big as an encyclopedia volume, and have calculated, then, how many bits of
information there are (1015). For each bit I allow 100 atoms. And it turns out that all of the information
that man has carefully accumulated in all the books in the world can be written in this form in a cube
of material 1/200 of an inch wide — which is the barest piece of dust that can be made out by the human
eye. So there is plenty of room at the bottom! Don’t tell me about microfilm! This fact — that enormous
amounts of information can be carried in an exceedingly small space — is, of course, well known to the

© 2003 by CRC Press LLC


1-4

Handbook of Nanoscience, Engineering, and Technology

biologists and resolves the mystery that existed before we understood all this clearly — of how it could
be that, in the tiniest cell, all of the information for the organization of a complex creature such as
ourselves can be stored. All this information — whether we have brown eyes, or whether we think at all,
or that in the embryo the jawbone should first develop with a little hole in the side so that later a nerve
can grow through it — all this information is contained in a very tiny fraction of the cell in the form of
long-chain DNA molecules in which approximately 50 atoms are used for one bit of information about
the cell.

Better Electron Microscopes
If I have written in a code with 5 × 5 × 5 atoms to a bit, the question is, how could I read it today? The
electron microscope is not quite good enough — with the greatest care and effort, it can only resolve
about 10 angstroms. I would like to try and impress upon you, while I am talking about all of these
things on a small scale, the importance of improving the electron microscope by a hundred times. It is
not impossible; it is not against the laws of diffraction of the electron. The wavelength of the electron in
such a microscope is only 1/20 of an angstrom. So it should be possible to see the individual atoms. What
good would it be to see individual atoms distinctly? We have friends in other fields — in biology, for
instance. We physicists often look at them and say, “You know the reason you fellows are making so little
progress?” (Actually I don’t know any field where they are making more rapid progress than they are in
biology today.) “You should use more mathematics, like we do.” They could answer us — but they’re
polite, so I’ll answer for them: “What you should do in order for us to make more rapid progress is to
make the electron microscope 100 times better.”
What are the most central and fundamental problems of biology today? They are questions like, what
is the sequence of bases in the DNA? What happens when you have a mutation? How is the base order
in the DNA connected to the order of amino acids in the protein? What is the structure of the RNA; is
it single-chain or double-chain, and how is it related in its order of bases to the DNA? What is the
organization of the microsomes? How are proteins synthesized? Where does the RNA go? How does it
sit? Where do the proteins sit? Where do the amino acids go in? In photosynthesis, where is the chlorophyll;
how is it arranged; where are the carotenoids involved in this thing? What is the system of the conversion
of light into chemical energy?
It is very easy to answer many of these fundamental biological questions; you just look at the thing!
You will see the order of bases in the chain; you will see the structure of the microsome. Unfortunately,
the present microscope sees at a scale which is just a bit too crude. Make the microscope one hundred
times more powerful, and many problems of biology would be made very much easier. I exaggerate, of
course, but the biologists would surely be very thankful to you — and they would prefer that to the
criticism that they should use more mathematics.
The theory of chemical processes today is based on theoretical physics. In this sense, physics supplies
the foundation of chemistry. But chemistry also has analysis. If you have a strange substance and you
want to know what it is, you go through a long and complicated process of chemical analysis. You can
analyze almost anything today, so I am a little late with my idea. But if the physicists wanted to, they
could also dig under the chemists in the problem of chemical analysis. It would be very easy to make an
analysis of any complicated chemical substance; all one would have to do would be to look at it and see
where the atoms are. The only trouble is that the electron microscope is 100 times too poor. (Later, I
would like to ask the question: can the physicists do something about the third problem of chemistry —
namely, synthesis? Is there a physical way to synthesize any chemical substance?)
The reason the electron microscope is so poor is that the f-value of the lenses is only 1 part to 1000;
you don’t have a big enough numerical aperture. And I know that there are theorems which prove that
it is impossible, with axially symmetrical stationary field lenses, to produce an f-value any bigger than
so and so; and therefore the resolving power at the present time is at its theoretical maximum. But in
every theorem there are assumptions. Why must the field be symmetrical? I put this out as a challenge:
is there no way to make the electron microscope more powerful?

© 2003 by CRC Press LLC


There’s Plenty of Room at the Bottom: An Invitation to Enter a New Field of Physics

1-5

The Marvelous Biological System
The biological example of writing information on a small scale has inspired me to think of something
that should be possible. Biology is not simply writing information; it is doing something about it. A
biological system can be exceedingly small. Many of the cells are very tiny, but they are very active;
they manufacture various substances; they walk around; they wiggle; and they do all kinds of marvelous
things — all on a very small scale. Also, they store information. Consider the possibility that we too
can make a thing very small which does what we want — that we can manufacture an object that
maneuvers at that level!
There may even be an economic point to this business of making things very small. Let me remind
you of some of the problems of computing machines. In computers we have to store an enormous
amount of information. The kind of writing that I was mentioning before, in which I had everything
down as a distribution of metal, is permanent. Much more interesting to a computer is a way of
writing, erasing, and writing something else. (This is usually because we don’t want to waste the
material on which we have just written. Yet if we could write it in a very small space, it wouldn’t
make any difference; it could just be thrown away after it was read. It doesn’t cost very much for
the material).

Miniaturizing the Computer
I don’t know how to do this on a small scale in a practical way, but I do know that computing machines
are very large; they fill rooms. Why can’t we make them very small, make them of little wires, little
elements — and by little, I mean little. For instance, the wires should be 10 or 100 atoms in diameter,
and the circuits should be a few thousand angstroms across. Everybody who has analyzed the logical
theory of computers has come to the conclusion that the possibilities of computers are very interesting
— if they could be made to be more complicated by several orders of magnitude. If they had millions
of times as many elements, they could make judgments. They would have time to calculate what is the
best way to make the calculation that they are about to make. They could select the method of analysis
which, from their experience, is better than the one that we would give to them. And in many other
ways, they would have new qualitative features.
If I look at your face I immediately recognize that I have seen it before. (Actually, my friends will say
I have chosen an unfortunate example here for the subject of this illustration. At least I recognize that it
is a man and not an apple.) Yet there is no machine which, with that speed, can take a picture of a face
and say even that it is a man; and much less that it is the same man that you showed it before — unless
it is exactly the same picture. If the face is changed; if I am closer to the face; if I am further from the
face; if the light changes — I recognize it anyway. Now, this little computer I carry in my head is easily
able to do that. The computers that we build are not able to do that. The number of elements in this
bone box of mine are enormously greater than the number of elements in our “wonderful” computers.
But our mechanical computers are too big; the elements in this box are microscopic. I want to make
some that are submicroscopic.
If we wanted to make a computer that had all these marvelous extra qualitative abilities, we would
have to make it, perhaps, the size of the Pentagon. This has several disadvantages. First, it requires too
much material; there may not be enough germanium in the world for all the transistors which would
have to be put into this enormous thing. There is also the problem of heat generation and power
consumption; TVA would be needed to run the computer. But an even more practical difficulty is that
the computer would be limited to a certain speed. Because of its large size, there is finite time required
to get the information from one place to another. The information cannot go any faster than the speed
of light — so, ultimately, when our computers get faster and faster and more and more elaborate, we
will have to make them smaller and smaller. But there is plenty of room to make them smaller. There is
nothing that I can see in the physical laws that says the computer elements cannot be made enormously
smaller than they are now. In fact, there may be certain advantages.

© 2003 by CRC Press LLC


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Handbook of Nanoscience, Engineering, and Technology

Miniaturization by Evaporation
How can we make such a device? What kind of manufacturing processes would we use? One possibility
we might consider, since we have talked about writing by putting atoms down in a certain arrangement,
would be to evaporate the material, then evaporate the insulator next to it. Then, for the next layer,
evaporate another position of a wire, another insulator, and so on. So, you simply evaporate until you
have a block of stuff which has the elements — coils and condensers, transistors and so on — of
exceedingly fine dimensions.
But I would like to discuss, just for amusement, that there are other possibilities. Why can’t we
manufacture these small computers somewhat like we manufacture the big ones? Why can’t we drill
holes, cut things, solder things, stamp things out, mold different shapes all at an infinitesimal level? What
are the limitations as to how small a thing has to be before you can no longer mold it? How many times
when you are working on something frustratingly tiny, like your wife’s wristwatch, have you said to
yourself, “If I could only train an ant to do this!” What I would like to suggest is the possibility of training
an ant to train a mite to do this. What are the possibilities of small but movable machines? They may
or may not be useful, but they surely would be fun to make.
Consider any machine — for example, an automobile — and ask about the problems of making an
infinitesimal machine like it. Suppose, in the particular design of the automobile, we need a certain
precision of the parts; we need an accuracy, let’s suppose, of 4/10,000 of an inch. If things are more
inaccurate than that in the shape of the cylinder and so on, it isn’t going to work very well. If I make the
thing too small, I have to worry about the size of the atoms; I can’t make a circle of “balls” so to speak,
if the circle is too small. So if I make the error — corresponding to 4/10,000 of an inch — correspond
to an error of 10 atoms, it turns out that I can reduce the dimensions of an automobile 4000 times,
approximately, so that it is 1 mm across. Obviously, if you redesign the car so that it would work with
a much larger tolerance, which is not at all impossible, then you could make a much smaller device.
It is interesting to consider what the problems are in such small machines. Firstly, with parts stressed
to the same degree, the forces go as the area you are reducing, so that things like weight and inertia are
of relatively no importance. The strength of material, in other words, is very much greater in proportion.
The stresses and expansion of the flywheel from centrifugal force, for example, would be the same
proportion only if the rotational speed is increased in the same proportion as we decrease the size. On
the other hand, the metals that we use have a grain structure, and this would be very annoying at small
scale because the material is not homogeneous. Plastics and glass and things of this amorphous nature
are very much more homogeneous, and so we would have to make our machines out of such materials.
There are problems associated with the electrical part of the system — with the copper wires and the
magnetic parts. The magnetic properties on a very small scale are not the same as on a large scale; there
is the “domain” problem involved. A big magnet made of millions of domains can only be made on a
small scale with one domain. The electrical equipment won’t simply be scaled down; it has to be
redesigned. But I can see no reason why it can’t be redesigned to work again.

Problems of Lubrication
Lubrication involves some interesting points. The effective viscosity of oil would be higher and higher
in proportion as we went down (and if we increase the speed as much as we can). If we don’t increase
the speed so much, and change from oil to kerosene or some other fluid, the problem is not so bad. But
actually we may not have to lubricate at all! We have a lot of extra force. Let the bearings run dry; they
won’t run hot because the heat escapes away from such a small device very, very rapidly.
This rapid heat loss would prevent the gasoline from exploding, so an internal combustion engine is
impossible. Other chemical reactions, liberating energy when cold, can be used. Probably an external
supply of electrical power would be most convenient for such small machines.
What would be the utility of such machines? Who knows? Of course, a small automobile would only
be useful for the mites to drive around in, and I suppose our Christian interests don’t go that far. However,
we did note the possibility of the manufacture of small elements for computers in completely automatic
© 2003 by CRC Press LLC


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