Topics in Applied PhysicsVolume 111

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Topics in Applied Physics

Topics in Applied Physics is a well-established series of review books, each of which presents a com-prehensive survey of a selected topic within the broad area of applied physics. Edited and written byleading research scientists in the field concerned, each volume contains review contributions cover-ing the various aspects of the topic. Together these provide an overview of the state of the art in therespective field, extending from an introduction to the subject right up to the frontiers of contempo-rary research.Topics in Applied Physics is addressed to all scientists at universities and in industry who wish toobtain an overview and to keep abreast of advances in applied physics. The series also provides easybut comprehensive access to the fields for newcomers starting research.Contributions are specially commissioned. The Managing Editors are open to any suggestions fortopics coming from the community of applied physicists no matter what the field and encourageprospective editors to approach them with ideas.

Managing EditorDr. Claus E. AscheronSpringer-Verlag GmbHTiergartenstr. 1769121 HeidelbergGermanyEmail: claus.ascheron@springer.com

Assistant Editor

Adelheid H. DuhmSpringer-Verlag GmbHTiergartenstr. 1769121 HeidelbergGermanyEmail: adelheid.duhm@springer.com

Ado Jorio, Gene Dresselhaus,Mildred S. Dresselhaus (Eds.)

Carbon Nanotubes

Advanced Topics in the Synthesis, Structure,Properties and Applications

With 250 Figures

123

Ado JorioDepartamento de Física,Universidade Federal de Minas Gerais(UFMG),Belo Horizonte, MG, 30.123-970andDivisão de Metrologia de Materiais,Instituto Nacional de Metrologia,Normalização e Qualidade Industrial(INMETRO),Duque de Caxias, RJ, 25250-020,Brazil

Gene DresselhausFrancis Bitter Magnet Lab,Massachusetts Institute of Technology,Cambridge, MA, 02139-4307USA

Mildred S. DresselhausDepartment of Physics and Department ofElectrical Engineering and Computer Science,Massachusetts Institute of TechnologyCambridge, MA, 02139-4307,USA

Library of Congress Control Number: 2007930205

Physics and Astronomy Classification Scheme (PACS): 06.20.-f, 61.48.DE, 85.35.Kt,78.67.Ch, 61.48.De

ISSN print edition: 0303-4216ISSN electronic edition: 1437-0859ISBN 978-3-540-72864-1 Springer Berlin Heidelberg New Yorke-ISBN 978-3-540-72865-8 Springer Berlin Heidelberg New YorkDOI 10.1071/978-3-540-72865-8

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Foreword

The Story Behind the Nanotube Rush

Nanotubes have evolved into one of the most intensively studied materialsand are held responsible for co-triggering the Nanotechnology Revolution.Why? This foreword attempts to provide a brief answer to “why” and “how”nanotubes have kept amazing both scientists and engineers over the pastdecades.

Even though nanotubes were commonly identified as contiguous hollowtubes in the core structure of carbon fibers in the 1970s [1], their popularityrose drastically following their observation on the cathode of a carbon arcused to produce fullerenes [2], the starting point of the Nanotube Rush era.Nanotubes, especially those of carbon, excite both fundamental scientists andengineers interested in applications due to the unique combination of theirproperties.

First, these molecular systems are nanometer-sized in diameter, but upto centimeters long, yielding an unprecedented length/diameter aspect ra-tio exceeding 107. Carbon nanotubes can be thought of as narrow stripsof graphene [3] rolled up into seamless tubes. They form spontaneouslyand efficiently under well-defined conditions either as single-wall nanotubes(SWNTs) or nested multiwall nanotubes (MWNTs). Contiguous carbonnanotubes exhibit a high degree of atomic-scale perfection. This fact, alongwith their close relationship with graphene, makes nanotubes chemically in-ert. As for graphene under tension, nanotubes are two orders of magnitudestronger than steel at 1/6th of the weight. The melting point of nanotubesof about 4000 K in “ideal vacuum” [4], close to that of graphite, exceedsthat of any metal. Depending on the atomic structure of nanotubes, includ-ing diameter, single-wall nanotubes act as ballistic conductors of electrons orshow semiconducting behavior. Carbon nanotubes seem to be also excellentconductors of heat, expected to exceed the record thermal conductivity ofisotopically pure diamond. Moreover, similar to the related graphite, carbonnanotubes appear to be biocompatible in many environments.

VI Foreword

Nanotube Applications Guiding the Way

Due to the amazing combination of their properties, nanotubes appear idealfor a wide range of current or future applications. Their high mechanicalstrength, combined with high electrical/thermal conductivity, allows the for-mation of strong, transparent, yet electrically and thermally conductive com-posites – including electromagnetic shielding of cables and conductive coat-ings of aircraft components – at relatively low loading levels of very few weightpercent. Nanotubes can also be spun into yarns with toughness competingwith Kevlar. Nanotube yarns can be knotted, plied, braided and woven intoconductive fabrics that remain tough even under ultraviolet radiation.

Due to the large aspect ratio, as near other “sharp” objects, the electricfield is locally enhanced by two orders of magnitude close to the tip of nano-tubes, thus significantly enhancing their field electron-emission properties.Since – unlike other cold cathodes – nanotubes have a high melting pointand maintain their high aspect ratio over time, they have a future as succes-sors of electron guns in cathode ray tube (CRT) displays with a significantadvantage: nanotube arrays attached to a substrate make bright, ultraflatdisplays, with each pixel lit by the current from several gated nanotubesbeneath it.

Due to their long electron mean-free path, single-wall carbon nanotubesare ballistic conductors of electrons and holes, which makes them appealingas building blocks of future molecular electronics circuits. Carbon-nanotube-based field-effect transistors surpass in all the relevant criteria current silicon-based devices at a small fraction of the size. Carbon nanotubes are also likelyto play a key role in future electronics applications, including spintronics andquantum computing.

Nanotubes have found a large-scale application as an additive to thegraphite component of Li-ion batteries. Forming an elastic filler, they absorbthe slack and prevent reorientation of graphite crystallites during their expan-sion/contraction associated with the intercalation/deintercalation of Li ions,thus increasing energy delivery and the number of useful charge/discharge cy-cles. High conductivity combined with a high surface-to-volume ratio opensup an application of nanotube assemblies as electrodes in supercapacitorsand fuel cells. Unusual arrangements of conductive and insulating nanotubeyarns may yield electronic fabrics with supercapacitor functionality.

Under various conditions, nanotube arrays appear to be biocompatiblewith human tissue. The combination of their nanometer-size diameter, well-defined cylindrical shape, and lack of chemical reactivity offer promise for theuse of nanotubes as efficient templates for the proliferation of neurons. Withcarbon nanotubes as an additive to nylon microcatheters used in surgery, theoccurrence of thrombus formation appears to be efficiently suppressed.

Even though no longer at the forefront of potential applications, reversiblehydrogen storage is likely to benefit from the light weight and large accessiblesurface area of nanotubes and related sp2-bonded carbon nanostructures.

Foreword VII

Reproducible measurements suggest the capability of carbon nanotubes tostore up to 2% (weight) molecular hydrogen at room temperature.

Nanotubes as a Test Ground of Fundamental Science

Even though it was the applications of nanotubes that grabbed most of themedia limelight, nanotubes themselves offer a unique possibility to explorefundamental properties of quasi-one-dimensional (1D) conductors and semi-conductors. For example, any phase transition – including the onset of su-perconductivity or magnetic ordering – should be suppressed in strictly one-dimensional systems. Furthermore, free carriers in one-dimensional conduc-tors have been postulated to behave as a Luttinger liquid rather than beingsubject to Fermi–Dirac statistics. The screening behavior of these 1D sys-tems modifies the optical properties of nanotubes significantly. An importantexample is the large binding energy of excitons that, in semiconducting nano-tubes, is two orders of magnitude larger than in 3D semiconductors and thuscomparable to their bandgap in typical semiconductors.

Problem Solution by Hand-in-Hand CollaborationBetween Experiment and Theory

Many initial problems have been solved since the beginning of the NanotubeRush era. Intensive collaboration between theory and experiment, especiallyin the field of single-wall nanotubes, became the key to rapid progress, whichcontinues until the present. Among the many examples, observed inconsis-tencies in nanotube conductivity measurements were reconciled by learninghow to make good contacts reproducibly. Also, superconducting behavior innanotubes was only observed after good contacts between nanotubes andleads were established. Still, many problems remain and await solution, in-cluding the controlled production of carbon nanotubes with a well-definedatomic (n, m) structure, which is a critical parameter in deciding whether aparticular SWNT is metallic or semiconducting, and whether it will performto the required specifications.

The entire arsenal of experimental and theoretical techniques that hadbeen developed to characterize low-dimensional systems, ranging from nano-particles to surfaces, has been applied to nanotubes. Nanotube metrology hasmatured to a well-established field affecting not only quality control, but alsoproviding guidance regarding the likely behavior of particular samples. Onthe experimental side, most direct information about the morphology of indi-vidual single- and multiwall tubes, including diameter and interlayer spacing,has been provided by high-resolution transmission electron microscopy. Ra-man spectroscopy has proven especially valuable in providing informationabout the fraction of graphitic carbon in the sample and determining the

VIII Foreword

distribution of nanotube diameters by analyzing the diameter-dependent ra-dial breathing mode. Photoluminescence spectra offer a powerful way to de-termine the chirality distribution among semiconducting nanotubes. Thesemethods are often combined with scanning probe microscopy and other spec-troscopic techniques to characterize nanotube samples in terms of uniformity,purity, chemical modifications, and defects.

Theoretical techniques used to investigate the relative stability and me-chanical properties of nanotubes range from continuum elasticity theory tobond-order potentials. Since the electronic structure in carbon nanotubes isdominated by 2pπ electronic states, the single ppπ band Huckel model hasproven very useful in understanding the electronic structure and quantumtransport in nanotubes. Ab initio density–functional theory (DFT) calcula-tions, or their parameterized tight-binding counterparts, are the methods ofchoice to determine the electronic structure and stability of pristine and func-tionalized nanotubes and related structures in the electronic ground state.Description of the excited-state dynamics of nanotubes requires calculationsbeyond DFT, including combinations of time-dependent DFT with molecu-lar dynamics, GW calculations of electronic spectra, and the Bethe–Salpeterequation to describe excitonic states.

Future of Carbon Nanotubes

In the first decade of the 21st century, almost two decades after the onsetof the Nanotube Rush, the nanotube field is as vital as ever. The rate ofpublications and patent applications in the field of nanotubes still continuesto increase. Whereas the stream of break-through discoveries has been hold-ing up until the present, other outstanding problems, identified in this book,still await solution. Cross-fertilization with emerging related fields, such asgraphene, will likely accelerate progress by providing insight from a differ-ent viewpoint. The continuing vitality of the nanotube field is unusual, whencompared to other research areas that initially appeared at least as appeal-ing, including the field of fullerenes and high-temperature superconductivity.Reasons for the unexpected evolution of the field in the recent past may bearhints about the future.

One feature that sets the field of nanotubes apart from other similarly ap-pealing areas is the wide field of promising applications, ranging from molec-ular electronics and quantum computing to materials science and medicine.Fundamental interest in the properties of this unusual material, combinedwith an apparently unlimited potential for applications, have sparked off in-ternational, interdisciplinary collaborations on a previously unprecedentedscale and demonstrated the benefits of such collaborations.

The intense need for communication among the disciplines has establishedsections dedicated to nanotube science at many conferences in different fields.The Internet offers web sites dedicated to nanotubes, linking the scientific

Foreword IX

nanotube community together and providing advice to the interested novice.Conferences dedicated to nanotubes, including the NT series initiated by theNT99 workshop in 1999, attract hundreds of scientists every year to newvenues and new countries. With their vision to provide access to informationfor all at minimum cost and to foster scientific collaboration between dif-ferent disciplines and cultures around the globe, nanotube conferences fulfillseveral worthy missions at the same time. Another appeal is their educationalmission, namely to give young aspiring scientists a fair chance for discussionwith their senior colleagues. The inspiration coming from days of intense in-formation exchange, where age differences are swept away in the heat of thediscussion, is likely to fuel the nanotube field for many more years to come.

Acknowledgements

This work was partly supported by the NSF NIRT grant ECS-0506309, theNSF NSEC grant EEC-0425826, and the Humboldt Foundation Award.

References

[1] A. Oberlin, M. Endo, T. Koyama, Filamentous growth of carbon through ben-zene decomposition, J. Cryst. Growth 32, 335 (1976).

[2] S. Iijima, Helical microtubules of graphitic carbon, Nature 354, 56 (1991).[3] Graphitic carbon is a layered structure. Graphene is a monolayer of graphite.[4] Computer simulations suggest that the melting temperature of nanotubes

should lie close to ≈4000 K, observed in high-purity graphite. The observedreduction of the melting point to above 3000 K has been linked to defects andresidual oxygen under experimental conditions.

Michigan, December 2007 David Tomanek

Preface

Over the past 15 years, carbon nanotubes have evolved into one of the mostintensively studied materials of this decade. Now, it seems clear that the car-bon nanotube field is on the verge of approaching a “phase transition criticalpoint”, which means the field is now mature for making the transition fromnanoscience to nanotechnology. This is therefore an important time to re-view what we have learned in the past decade and, most important, to lookinto the future of carbon nanotubes and related fields. The general goal forthis book is to review research highlights for the past decade and to pointto research opportunities for the future. This book builds on the best-sellingSpringer publication of 2001 in the Topics in Applied Physics Series vol-ume 80 on Carbon Nanotubes and features reviews of many topics that haveevolved since that publication. The present book is directed to both the verylarge number of researchers now working in the field, as well as the manynew entrants looking for useful applications of the special properties of car-bon nanotubes. In the spirit of these goals, the present volume has sought tobring leaders in the field of carbon nanotube research to summarize, using atutorial style, the important advances occurring during the past decade andto point to some promising future research directions for the carbon nanotubefield. Most of the chapters are written by a collection of authors from differ-ent groups worldwide, guaranteeing a broad view of each topic, rather thanreflecting the work of specific research groups. We are thankful to the au-thors who produced excellent chapters that will greatly benefit many readersinterested in carbon nanotubes and related topics, and to Springer-Verlag forcooperating with us in implementing this project. A.J. personally acknowl-edges financial support from CNPq, Fapemig, CAPES, Rede Nacional dePesquisa em Nanotubos de Carbono and Instituto de Nanotecnologia (CNPqand MCT), Brazil, and G.D. and M.S.D. acknowledge NSF-DMR 04-05538.

Belo Horizonte, December 2007 Ado JorioGene Dresselhaus

Mildred S. Dresselhaus

Contents

Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VReferences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IX

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . XI

Introduction to the Important and Exciting Aspects ofCarbon-Nanotube Science and TechnologyDavid Tomanek, Ado Jorio, Mildred S. Dresselhaus, and GeneDresselhaus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Applications and Metrology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Synthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 Defect Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 Mechanical and Thermal Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 Electronic Structure and Atomic Arrangement . . . . . . . . . . . . . . . . . . 67 Advances in Photophysics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 Transport Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 Double-Wall Carbon Nanotubes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1010 Chemical Reactivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1011 Related Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1012 Graphene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1113 Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Potential Applications of Carbon NanotubesMorinobu Endo, Michael S. Strano, and Pulickel M. Ajayan . . . . . . . . . . 131 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132 Applications of Carbon Nanotubes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

2.1 Carbon Nanotubes in Electronics . . . . . . . . . . . . . . . . . . . . . . . . . 172.2 Carbon Nanotubes in Energy Applications . . . . . . . . . . . . . . . . . 222.3 Carbon Nanotubes for Mechanical Applications . . . . . . . . . . . . . 272.4 Carbon-Nanotube Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 312.5 Carbon Nanotubes in Field Emission

and Lighting Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 362.6 Carbon Nanotubes for Biological Applications . . . . . . . . . . . . . . 38

XIV Contents

2.7 Carbon Nanotubes in Miscellaneous Applications . . . . . . . . . . . 422.8 Environmental and Health Effects of Carbon Nanotubes . . . . . 45

3 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Carbon-Nanotube MetrologyAdo Jorio, Esko Kauppinen, and Abdou Hassanien . . . . . . . . . . . . . . . . . 631 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 632 Electronic Microscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 652.2 Sample Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 662.3 Morphology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 672.4 Atomic Structure by HRTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . 682.5 Chiral Indices Determination by Electron Diffraction . . . . . . . . 70

2.5.1 Bessel-Function Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . 702.5.2 Intrinsic Layerline Distance Analysis . . . . . . . . . . . . . . . . . 70

3 Scanning Probe Microscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 713.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 713.2 Sample Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 733.3 Imaging the Structure and Electronic Properties of SWNTs . . 733.4 Single-Electron States of SWNTs . . . . . . . . . . . . . . . . . . . . . . . . . 763.5 Defects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 773.6 Local Vibrational Spectroscopy in SWNTs . . . . . . . . . . . . . . . . . 78

4 Optics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 794.1 Basic Principles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 794.2 Optical Absorption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 824.3 Resonance Raman Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . . . . 83

4.3.1 The Radial Breathing Mode (RBM) . . . . . . . . . . . . . . . . . 854.3.2 The Tangential Modes (G Band) . . . . . . . . . . . . . . . . . . . . 874.3.3 The Disorder-Induced Feature (D Band) . . . . . . . . . . . . . 894.3.4 Other Raman Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

4.4 Photoluminescence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 905 Summary and Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

Carbon Nanotube Synthesis and OrganizationErnesto Joselevich, Hongjie Dai, Jie Liu, Kenji Hata,and Alan H. Windle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1011 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1022 Bulk Production Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

2.1 Arc Discharge and Laser Vaporization . . . . . . . . . . . . . . . . . . . . . 1032.2 Chemical Vapor Deposition (CVD). . . . . . . . . . . . . . . . . . . . . . . . 1032.3 Mass Production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

Contents XV

2.4 Toward Selective Synthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1063 Purification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

3.1 Dry Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1073.2 Wet Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

4 Sorting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1094.1 Classification of Sorting Methods and Selective Processes . . . . 1094.2 Nondestructive Sorting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1104.3 Selective Elimination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1144.4 General Principles and Perspectives of Sorting . . . . . . . . . . . . . . 115

5 Organization into Fibers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1165.1 Processing Principles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1175.2 Liquid Suspensions of Carbon Nanotubes . . . . . . . . . . . . . . . . . . 1185.3 Spinning Carbon Nanotube Fibers from Liquid-

Crystalline Suspensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1195.4 Wet Spinning of CNT Composite Fibers . . . . . . . . . . . . . . . . . . . 1205.5 Dry Spinning from Carbon Nanotube Forests . . . . . . . . . . . . . . . 1225.6 Direct Spinning from Carbon Nanotube Fibers

from the CVD Reaction Zone . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1236 Organization on Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

6.1 Vertically Aligned Growth and Supergrowth . . . . . . . . . . . . . . . . 1266.1.1 Supergrowth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1266.1.2 SWNT-Solid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

6.2 Organized Assembly of Preformed Nanotubes . . . . . . . . . . . . . . 1336.3 Horizontally Aligned Growth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137

6.3.1 Field-Directed Growth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1376.3.2 Flow-Directed Growth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1396.3.3 Surface-Directed Growth: “Nanotube Epitaxy” . . . . . . . . 1416.3.4 Patterned Growth on Surfaces . . . . . . . . . . . . . . . . . . . . . . 147

7 Summary and Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163

Mechanical Properties, Thermal Stability and HeatTransport in Carbon NanotubesTakahiro Yamamoto, Kazuyuki Watanabe, and Eduardo R. Hernandez 1651 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1652 Mechanical Properties and Thermal Stability of Nanotubes . . . . . . . 167

2.1 Elasticity at the Nanoscale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1672.2 Mechanical Properties of Nanotubes: Elastic Regime . . . . . . . . 1672.3 Beyond the Elastic Regime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1722.4 Thermal Stability of Nanotubes . . . . . . . . . . . . . . . . . . . . . . . . . . 1752.5 Summary of Mechanical Properties and Thermal Stability . . . 177

3 Heat-Transport Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1783.1 Ballistic Heat Transport in SWNTs . . . . . . . . . . . . . . . . . . . . . . . 178

3.1.1 Landauer Theory for Phonon Transport . . . . . . . . . . . . . . 178

XVI Contents

3.1.2 Quantization of Thermal Conductance . . . . . . . . . . . . . . . 1803.1.3 Electron Contribution to the Thermal Conductance . . . . 181

3.2 Quasiballistic Heat Transport in SWNTs . . . . . . . . . . . . . . . . . . 1823.2.1 Length Effect of the Thermal Conductivity . . . . . . . . . . . 1823.2.2 Influence of Defects on the Thermal Conductivity . . . . . 184

3.3 Diffusive Heat Transport in SWNTs . . . . . . . . . . . . . . . . . . . . . . . 1853.4 Heat Transport in MWNTs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1863.5 Summary of Heat Transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188

4 Summary and Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194

Quasiparticle and Excitonic Effects in the Optical Responseof Nanotubes and NanoribbonsCatalin D. Spataru, Sohrab Ismail-Beigi, Rodrigo B. Capaz, andSteven G. Louie . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1951 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1962 Methodology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1973 First-Principles Studies of the Optical Spectra of SWNTs . . . . . . . . 1994 Diameter and Chirality Dependence of Exciton Properties . . . . . . . . 2045 Symmetries and Selection Rules of Excitons . . . . . . . . . . . . . . . . . . . . 2066 Radiative Lifetime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2107 Pressure, Strain and Temperature Effects . . . . . . . . . . . . . . . . . . . . . . . 2148 Related Structures: Boron-Nitride Nanotubes

and Graphene Nanoribbons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2169 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227

Role of the Aharonov–Bohm Phase in the Optical Propertiesof Carbon NanotubesTsuneya Ando . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2291 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2292 Effective-Mass Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2293 Excitons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2334 Exciton Fine Structure and Aharonov–Bohm Effect . . . . . . . . . . . . . . 2365 Exciton Absorption for Crosspolarized Light . . . . . . . . . . . . . . . . . . . . 2406 Optical Phonons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249

Excitonic States and Resonance Raman Spectroscopyof Single-Wall Carbon NanotubesRiichiro Saito, Cristiano Fantini, and Jie Jiang . . . . . . . . . . . . . . . . . . . . . 2511 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251

1.1 Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251

Contents XVII

1.2 Overview of Resonance Raman Measurements . . . . . . . . . . . . . . 2521.3 Overview of the Raman Intensity Calculation . . . . . . . . . . . . . . 253

2 Measurement of Raman Spectra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2552.1 Raman Spectra of SWNTs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2552.2 The Radial Breathing Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2552.3 G-Band . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2572.4 D-Band . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2602.5 G′-Band . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2612.6 Intermediate-Frequency Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . 2622.7 Other Two-Phonon Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264

3 Resonance Raman Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2643.1 Experimental Optical Transition Energies . . . . . . . . . . . . . . . . . . 264

4 Electron–Phonon and Electron–Photon Matrix Elements . . . . . . . . . 2674.1 Extended Tight-Binding Method for Electrons and Phonons . . 2674.2 Dipole Approximation for the Optical Matrix Element . . . . . . . 2694.3 Electron–Phonon Matrix Element Calculation . . . . . . . . . . . . . . 2704.4 Extension to the Exciton Matrix Element Calculation . . . . . . . 2724.5 Raman Intensity Calculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2754.6 RBM and G-Band: Length, Type, Chirality,

and Diameter Dependence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2765 Future Directions, Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285

Photoluminescence: Science and ApplicationsJacques Lefebvre, Shigeo Maruyama, and Paul Finnie . . . . . . . . . . . . . . . 2871 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2872 Basic Photoluminescence Spectroscopy of Isolated Nanotubes . . . . . 288

2.1 Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2882.2 Absorption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2902.3 Photoluminescence from Isolated SWNTs . . . . . . . . . . . . . . . . . . 2912.4 Photoluminescence Excitation Map . . . . . . . . . . . . . . . . . . . . . . . 2932.5 Exciton Picture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296

3 Spectroscopic Properties of Nanotube Photoluminescence . . . . . . . . . 2983.1 Lineshape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2983.2 Polarization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2993.3 Quantum Efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3003.4 Photoluminescence Imaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3033.5 Time Dependence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3043.6 Phonons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305

4 Physical and Chemical Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3064.1 External Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3064.2 External Physical Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308

5 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3105.1 Nanotube Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 310

XVIII Contents

5.2 Wider Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3126 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318

Ultrafast Spectroscopy of Carbon NanotubesYing-Zhong Ma, Tobias Hertel, Zeev Valy Vardeny,Graham R. Fleming, and Leonas Valkunas . . . . . . . . . . . . . . . . . . . . . . . . . 3211 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3212 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 322

2.1 Instrumentation for Ultrafast Spectroscopy . . . . . . . . . . . . . . . . . 3222.2 Basics of Nonlinear Optics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324

3 Metallic Tubes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3274 Semiconducting Tubes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 328

4.1 Exciton Dynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3294.2 Low Excitation Densities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 330

4.2.1 Intersubband Relaxation . . . . . . . . . . . . . . . . . . . . . . . . . . . 3314.2.2 Radiative Lifetime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3314.2.3 Correlation of the PL Decay Timescales

with the Tube Diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3324.2.4 Environmental and Temperature Effects

on Exciton Population Dynamics . . . . . . . . . . . . . . . . . . . . 3334.2.5 Transient Absorption of a Chirality-

Enriched SWNT Preparation . . . . . . . . . . . . . . . . . . . . . . . 3364.3 High Excitation Densities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 338

4.3.1 Spectroscopic and Dynamic Signatures of High-Intensity Excitation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 338

4.3.2 Theoretical Advances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3424.3.3 Exciton Dissociation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 343

5 Comparison of S-SWNTs with π-Conjugated Polymers . . . . . . . . . . . 3446 Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 346References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 352

Rayleigh Scattering SpectroscopyTony F. Heinz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3531 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3532 Elastic Light Scattering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3543 Experimental Technique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3564 Application of the Technique. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360

4.1 Electronic Transitions of Nanotubesof Independently Determined Structure . . . . . . . . . . . . . . . . . . . . 360

4.2 Polarization Dependence of Nanotube Electronic Transitions . 3614.3 Structural Stability Along the Nanotube Axis . . . . . . . . . . . . . . 3624.4 Nanotube–Nanotube Interactions . . . . . . . . . . . . . . . . . . . . . . . . . 363

Contents XIX

5 Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 368

New Techniques for Carbon-Nanotube Studyand CharacterizationAchim Hartschuh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3711 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3712 Near-Field Optical Microscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 371

2.1 Experimental . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3722.2 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 373

2.2.1 Nanoscale Optical Imaging . . . . . . . . . . . . . . . . . . . . . . . . . 3732.2.2 Nanoscale Optical Spectroscopy . . . . . . . . . . . . . . . . . . . . . 375

2.3 Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3773 Phonon Spectroscopy Using Inelastic Electron Tunneling . . . . . . . . . 378

3.1 Experimental . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3783.2 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3793.3 Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 382

4 Coherent Phonon Generation and Detection . . . . . . . . . . . . . . . . . . . . 3834.1 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3844.2 Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 389

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 389Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 392

High Magnetic Field Phenomenain Carbon NanotubesJunichiro Kono, Robin J. Nicholas, and Stephan Roche . . . . . . . . . . . . . . 3931 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3932 Band Structure in Magnetic Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . 394

2.1 Parallel Field: Role of the Aharonov–Bohm Phase . . . . . . . . . . . 3942.2 Perpendicular Field: Onset of Landau Levels . . . . . . . . . . . . . . . 395

3 Magnetization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3973.1 Theory of the Magnetic Susceptibility . . . . . . . . . . . . . . . . . . . . . 3973.2 Magnetic-Susceptibility Measurements . . . . . . . . . . . . . . . . . . . . . 399

4 Magneto-transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4004.1 Disorder and Quantum Interference . . . . . . . . . . . . . . . . . . . . . . . 4014.2 Weak Localization and Magnetoresistance Oscillations . . . . . . . 4014.3 Most Recent Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 404

5 Magneto-Optics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4055.1 Bandgap Shrinkage and Aharonov–Bohm Splitting . . . . . . . . . . 4065.2 Magnetic Brightening of “Dark” Excitons: Theory . . . . . . . . . . 4075.3 Magnetic Brightening of “Dark” Excitons: Experiment . . . . . . 4105.4 Perpendicular Field Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 414

6 Summary and Remaining Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . 415References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 416

XX Contents

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 421

Carbon-Nanotube OptoelectronicsPhaedon Avouris, Marcus Freitag, and Vasili Perebeinos . . . . . . . . . . . . . 4231 The Nature of the Optically Excited State . . . . . . . . . . . . . . . . . . . . . . 4232 Exciton Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 425

2.1 Low-Energy Exciton Bandstructure –Dark and Bright Excitons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 425

2.2 Exciton Radiative and Nonradiative Lifetimes . . . . . . . . . . . . . . 4272.3 Exciton–Optical Phonon Sidebands in Absorption Spectra . . . 4282.4 Impact Excitation, Auger Recombination

and Exciton Annihilation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4302.5 Franz–Keldysh, Stark Effects and Exciton Ionization

by Electric Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4333 Overview of CNT Electronics – Unipolar and Ambipolar FETs . . . . 4354 Photoconductivity and Light Detection . . . . . . . . . . . . . . . . . . . . . . . . 436

4.1 Types of Nanotube Photodetectors . . . . . . . . . . . . . . . . . . . . . . . . 4364.2 CNT Photoconductor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4374.3 Photocurrent Spectroscopy and Quantum Efficiency . . . . . . . . . 4374.4 Photovoltage in Asymmetric CNTFETs –

Schottky-Barrier Diodes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4394.5 Photovoltage in a CNT p–n Junction . . . . . . . . . . . . . . . . . . . . . . 4404.6 Photovoltage Imaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 441

5 Electroluminescence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4425.1 Ambipolar Mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4425.2 Mechanism of the Spot Movement in Ambipolar Transistors . . 4435.3 Electroluminescence Spectrum and Efficiency

of the Radiative Decay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4446 Unipolar Mechanism for Infrared Emission . . . . . . . . . . . . . . . . . . . . . . 4447 Conclusions – Future . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 446References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 448Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 453

Electrical Transport in Single-Wall Carbon NanotubesMichael J. Biercuk, Shahal Ilani, Charles M. Marcus,and Paul L. McEuen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4551 Introduction and Basic Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 455

1.1 Band Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4561.2 1D Transport in Nanotubes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 458

2 Classical (Incoherent) Transport in Nanotubes . . . . . . . . . . . . . . . . . . 4602.1 Contacts to Nanotubes: Schottky Barriers . . . . . . . . . . . . . . . . . 4602.2 The Effect of Disorder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4632.3 Electron–Phonon Scattering in Nanotubes . . . . . . . . . . . . . . . . . 464

3 Nanotube Devices and Advanced Geometries . . . . . . . . . . . . . . . . . . . 4663.1 High-Performance Transistors . . . . . . . . . . . . . . . . . . . . . . . . . . . . 467

Contents XXI

3.2 Radio-Frequency and Microwave Devices . . . . . . . . . . . . . . . . . . . 4693.3 P–N Junction Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 470

4 Quantum Transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4744.1 Quantum Transport in One Dimension . . . . . . . . . . . . . . . . . . . . 474

4.1.1 Luttinger Liquid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4744.1.2 Ballistic Transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 476

4.2 Superconducting Proximity Effect . . . . . . . . . . . . . . . . . . . . . . . . . 4764.3 Quantum Transport with Ferromagnetic Contacts . . . . . . . . . . . 478

5 Nanotube Quantum Dots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4795.1 Single Dots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4805.2 Band and Spin Effects in Single Quantum Dots . . . . . . . . . . . . . 480

5.2.1 Shell Filling in Nanotube Dots . . . . . . . . . . . . . . . . . . . . . . 4805.2.2 Nanotube Dots with Ferromagnetic Contacts . . . . . . . . . 481

5.3 Kondo Effects in Nanotube Dots . . . . . . . . . . . . . . . . . . . . . . . . . . 4815.3.1 Nonequilibrium Singlet–Triplet Kondo Effect . . . . . . . . . . 4825.3.2 Orbital and SU(4) Kondo . . . . . . . . . . . . . . . . . . . . . . . . . . 482

5.4 Multiple Quantum Dots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4836 Future Directions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 484References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 485Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 492

Double-Wall Carbon NanotubesRudolf Pfeiffer, Thomas Pichler, Yoong Ahm Kim, and Hans Kuzmany 4951 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 495

1.1 Fingerprints of Double-Wall Carbon Nanotubes . . . . . . . . . . . . . 4962 Preparation of Double-Wall Carbon Nanotubes . . . . . . . . . . . . . . . . . . 496

2.1 DWNT Growth from Chemical Vapor Deposition . . . . . . . . . . . 4972.2 DWNT Growth from Precursor Material . . . . . . . . . . . . . . . . . . . 501

2.2.1 DWNT Growth from Fullerene Peapods . . . . . . . . . . . . . . 5012.2.2 DWNT Growth from Ferrocene . . . . . . . . . . . . . . . . . . . . . 5032.2.3 DWNT Growth from Other Carbon Precursors . . . . . . . . 5062.2.4 Theoretical Models for the Fullerene Coalescence . . . . . . 507

3 Properties and Applications of DWNTs . . . . . . . . . . . . . . . . . . . . . . . . 5083.1 Electronic and Optical Properties, Transport . . . . . . . . . . . . . . . 508

3.1.1 Model Calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5093.1.2 Experimental Results for Electronics and Structure . . . . 5113.1.3 Transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 511

3.2 Raman Scattering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5123.2.1 The Nature of the Radial Breathing Mode Response . . . 5133.2.2 Tangential Modes and Overtones . . . . . . . . . . . . . . . . . . . . 5133.2.3 Temperature, Pressure, and Doping Effects . . . . . . . . . . . 514

3.3 13C Substitution and Nuclear Magnetic Resonance . . . . . . . . . . 5163.4 Thermal and Chemical Stability, Mechanical Properties . . . . . . 517

3.4.1 Thermal Stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 518

XXII Contents

3.4.2 Pore Structure and Oxidative Stabilityof the Bundled DWNTs . . . . . . . . . . . . . . . . . . . . . . . . . . . 518

3.4.3 Mechanical Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5204 Summary and Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 521

4.1 Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 522References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 523Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 530

Doped Carbon Nanotubes: Synthesis, Characterizationand ApplicationsMauricio Terrones, Antonio G. Souza Filho, and Apparao M. Rao . . . . 5311 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5312 Exohedral Doping or Intercalation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5323 Endohedral Doping or Encapsulation . . . . . . . . . . . . . . . . . . . . . . . . . . 5334 Inplane or Substitutional Doping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 534

4.1 Substitutional Doping in Graphite . . . . . . . . . . . . . . . . . . . . . . . . 5344.2 Substitutional Doping in Nanotubes . . . . . . . . . . . . . . . . . . . . . . . 5344.3 Synthesis Methods for Substitutional Doped Nanotubes . . . . . 537

4.3.1 Arc-Discharge Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5374.3.2 Laser-Ablation Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5374.3.3 Chemical Vapor Deposition . . . . . . . . . . . . . . . . . . . . . . . . . 5384.3.4 B and N Substitution Reactions . . . . . . . . . . . . . . . . . . . . . 5384.3.5 Plasma-Assisted CVD. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 540

5 Characterization Techniques for Studying Doped Nanotubes . . . . . . 5405.1 Morphological and Structural Characterization . . . . . . . . . . . . . 540

5.1.1 Atomic Structure of N-Doped MWNTs . . . . . . . . . . . . . . . 5415.1.2 Atomic Structure of B-Doped MWNTs . . . . . . . . . . . . . . . 5425.1.3 Atomic Structure of Doped SWNTs . . . . . . . . . . . . . . . . . 542

5.2 Electronic and Transport Characterization . . . . . . . . . . . . . . . . . 5435.3 Raman Characterization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 546

5.3.1 Nonsubstitutional n-Type Doped Nanotubes . . . . . . . . . . 5465.3.2 Nonsubstitutional p-Type Doped Nanotubes . . . . . . . . . . 5505.3.3 Raman Spectroscopy for Inplane Doped Nanotubes . . . . 551

6 Applications of Doped Nanotubes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5537 Perspectives and Challenges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 555References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 558Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 566

Electrochemistry of Carbon NanotubesLadislav Kavan and Lothar Dunsch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5671 Electrochemistry of Nanotubes: Fundamentals . . . . . . . . . . . . . . . . . . 567

1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5671.2 Potential-Dependent Reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . 5681.3 Faradaic and Non-Faradaic Processes

in Nanocarbons (Nanotubes, Fullerenes) . . . . . . . . . . . . . . . . . . . 569

Contents XXIII

1.4 Doping of Nanocarbons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5712 Experimental Techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 575

2.1 Materials in Electrochemical Studies of Nanotubes . . . . . . . . . . 5752.2 Voltammetry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5752.3 Methods of Spectroelectrochemistry . . . . . . . . . . . . . . . . . . . . . . . 578

3 Practical Applications of Charge Transfer at Nanotubes . . . . . . . . . . 5793.1 Electrochemical Synthesis and Behavior of Nanotubes . . . . . . . 5793.2 Practical Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 580

4 Spectroelectrochemistry of Nanotubes . . . . . . . . . . . . . . . . . . . . . . . . . . 5824.1 Vis-NIR Spectroelectrochemistry . . . . . . . . . . . . . . . . . . . . . . . . . 5824.2 Raman Spectroelectrochemistry . . . . . . . . . . . . . . . . . . . . . . . . . . 585

4.2.1 SWNTs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5864.2.2 Fullerene Peapods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5894.2.3 Double-Walled Carbon Nanotubes . . . . . . . . . . . . . . . . . . . 589

4.3 Combined Chemical/Electrochemical Doping . . . . . . . . . . . . . . . 5924.4 Single-Nanotube Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 593

5 Summary and Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 594References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 595Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 602

Single-Wall Carbon Nanohorns and NanoconesMasako Yudasaka, Sumio Iijima, and Vincent H. Crespi . . . . . . . . . . . . . 6051 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6052 Geometrical Definition of the Cone . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6063 Structure, Production, and Growth Mechanism

of Single-Wall Carbon Nanohorns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6074 Properties of Single-Wall Nanohorns . . . . . . . . . . . . . . . . . . . . . . . . . . . 6115 Applications of Single-Wall Nanohorns . . . . . . . . . . . . . . . . . . . . . . . . . 6126 Comparison of Single-Wall Nanohorns

to Single-Wall Nanotubes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6167 Mechanical Response of Carbon Nanocones . . . . . . . . . . . . . . . . . . . . . 6178 Electronic Properties of Carbon Cones . . . . . . . . . . . . . . . . . . . . . . . . . 6199 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 622References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 622Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 628

Inorganic Nanotubes and Fullerene-Like Structures (IF)R. Tenne, M. Remskar, A. Enyashin, and G. Seifert . . . . . . . . . . . . . . . . . 6311 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6312 Synthesis of INT and IF Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 634

2.1 Physical Techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6342.2 Soft Chemistry “Chemie Douce” . . . . . . . . . . . . . . . . . . . . . . . . . . 6372.3 High-Temperature Reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 639

3 Structural Characterization and Stability . . . . . . . . . . . . . . . . . . . . . . . 6413.1 General Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 641

XXIV Contents

3.2 Strain-Relaxation Mechanisms in the Nanotubes . . . . . . . . . . . . 6433.3 Studies of Some Specific Systems . . . . . . . . . . . . . . . . . . . . . . . . . 645

4 Physical Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6494.1 Mechanical Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6494.2 Electronic and Optical Properties . . . . . . . . . . . . . . . . . . . . . . . . . 651

5 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6555.1 Tribological Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6555.2 Towards High-Strength Nanocomposites . . . . . . . . . . . . . . . . . . . 6565.3 Li Intercalation and Hydrogen Sorption in MS2 Nanotubes . . . 6565.4 Solar Cells, Photocatalysis and Sensors . . . . . . . . . . . . . . . . . . . . 6575.5 Biotechnology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6585.6 Catalysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 658

6 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 659References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 660Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 669

Electron and Phonon Properties of Graphene: TheirRelationship with Carbon NanotubesJ.-C. Charlier, P. C. Eklund J. Zhu, A. C. Ferrari . . . . . . . . . . . . . . . . . . . 6731 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6732 Electronic Properties and Transport Measurements . . . . . . . . . . . . . . 675

2.1 Graphene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6752.1.1 Electronic Band Structure . . . . . . . . . . . . . . . . . . . . . . . . . . 6752.1.2 Transport Measurements in Single-Layer Graphene . . . . 678

2.2 Graphene Nanoribbons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6812.3 Graphite and n-Graphene Layer Systems . . . . . . . . . . . . . . . . . . 684

3 Optical Phonons and Raman Spectroscopy . . . . . . . . . . . . . . . . . . . . . 6863.1 Raman D and G Bands, Double Resonance

and Kohn Anomalies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6863.2 Electron–Phonon Coupling from Phonon Dispersions

and Raman Linewidths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6893.3 The Raman Spectrum of Graphene

and n-Graphene Layer Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . 6903.4 Doped Graphene: Breakdown of the Adiabatic Born–

Oppenheimer Approximation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6944 Implications for Phonons and Raman Scattering in Nanotubes . . . . 697

4.1 Adiabatic Kohn Anomalies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6974.2 Nonadiabatic Kohn Anomalies . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6984.3 The Raman G Peak of Nanotubes . . . . . . . . . . . . . . . . . . . . . . . . 698

5 Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 701References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 701Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 708

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 711