Tománek / Enbody Science and Application of Nanotubes

1. Auflage 2005
ISBN: 978-0-306-47098-1
Verlag: Springer US
Format: PDF
Kopierschutz: 1 - PDF Watermark

E-Book, Englisch, 395 Seiten

Reihe: Fundamental Materials Research

This volume is a result of the Nanotube '99 Workshop, held in late July 1999. It is the most up-to-date compendium representing the state of the art in the rapidly developing field of nanotubes. An important focus is on the relative merits of the various techniques used to synthesize nanotubes of carbon and other materials. Another important issue addressed is the effect of synthesis conditions on the multitude of morphologies that have by now been observed, and the characterization of the structures. Important advances are reported in the understanding of mechanical and chemical properties of nanotubes, including their potential use for hydrogen storage and nano-manipulators in micro-electromechanical systems (MEMS). The unusual electronic properties of nanotubes, which seem to attract most attention in the field, are represented accordingly, alongside the first likely commercial application of nanotubes in high-efficiency flat-panel displays.

Autoren/Hrsg.

Tománek, D.

Enbody, R. J.

Inhaltsverzeichnis

1;SERIES PREFACE;6
2;PREFACE;8
3;CONTENTS;11
4;FILLING CARBON NANOTUBES USING AN ARC DISCHARGE;15
4.1;ABSTRACT;15
4.2;INTRODUCTION;15
4.3;EXPERIMENTAL PROCEDURES;17
4.4;STRUCTURAL AND CHEMICAL ANALYSIS;17
4.5;ANALYSIS OF THE ROLE OF SULFUR;24
4.6;DISCUSSION: GROWTH MECHANISM;24
4.7;CONCLUSION;29
5;SIMULATION OF STM IMAGES AND STS SPECTRA OF CARBON NANOTUBES;31
5.1;INTRODUCTION;31
5.2;STM THEORY;32
5.3;GRAPHITE;34
5.4;PERFECT NANOTUBES;36
5.5;STM images;38
5.6;MULTI-WALL NANOTUBES AND ROPES;41
5.7;DEFECTS IN NANOTUBES;42
5.8;CONCLUSIONS;45
5.9;ACKNOWLEDGMENT;45
5.10;REFERENCES;45
6;APPLICATIONS RESEARCH ON VAPOR-GROWN CARBON FIBERS;48
6.1;VAPOR-GROWN CARBON FIBERS;48
6.2;INFILTRATION;51
6.3;COMPARATIVE FIBER PROPERTIES;54
6.4;COMPOSITE THEORY;54
6.5;SURFACE TREATMENTS;57
6.6;PROPERTIES IMPROVEMENTS;61
6.7;ELECTRICAL CONDUCTIVITY;62
6.8;ACKNOWLEDGMENTS;63
6.9;REFERENCES;63
7;THE GROWTH OF CARBON AND BORON NITRIDE NANOTUBES: A QUANTUM MOLECULAR DYNAMICS STUDY;65
7.1;INTRODUCTION;65
7.2;1. MICROSCOPIC GROWTH MECHANISMS FOR CARBON NANOTUBES;66
7.3;2. FRUSTRATION EFFECTS AND GROWTH MECHANISMS FOR BORONNITRIDE NANOTUBES;70
7.4;CONCLUSION;75
7.5;ACKNOWLEDGEMENTS;76
7.6;REFERENCES;76
8;NANOSCOPIC HYBRID MATERIALS: THE SYNTHESIS, STRUCTURE AND PROPERTIES OF PEAPODS, CATS AND KIN;78
8.1;INTRODUCTION;78
8.2;EXPERIMENTAL METHOD;78
8.3;EXPERIMENTAL RESULTS AND DISCUSSION;79
8.4;SUMMARY;85
8.5;ACKNOWLEDGEMENTS.;86
8.6;REFERENCES;86
9;LINEAR AUGMENTED CYLINDRICAL WAVE METHOD FOR NANOTUBES: BAND STRUCTURE OF;88
9.1;INTRODUCTION;88
9.2;FORMALISM;88
9.3;APPLICATIONS;92
9.4;ACKNOWLEDGEMENT;93
9.5;REFERENCES;93
10;COMPARATIVE STUDY OF A COILED CARBON NANOTUBE BY ATOMIC FORCE MICROSCOPY AND SCANNING ELECTRON MICROSCOPY;94
10.1;ABSTRACT;94
10.2;INTRODUCTION;94
10.3;EXPERIMENTAL;96
10.4;RESULTS;96
10.5;CONCLUSION;101
10.6;ACKNOWLEDGMENTS;102
10.7;REFERENCES;102
11;INVESTIGATION OF THE DEFORMATION OF CARBON NANOTUBE COMPOSITES THROUGH THE USE OF RAMAN SPECTROSCOPY;103
11.1;ABSTRACT;103
11.2;INTRODUCTION;103
11.3;EXPERIMENTAL;104
11.4;RESULTS AND DISCUSSION;105
11.5;Deformation of SWNT Nanocomposites;108
11.6;Multi-Walled Nanotubes;110
11.7;Reinforcement of Epoxy Resin with Carbon Nanotubes;110
11.8;CONCLUSIONS;111
11.9;ACKNOWLEDGEMENTS;112
11.10;REFERENCES;112
12;ELECTRONIC STATES, CONDUCTANCE AND LOCALIZATION IN CARBON NANOTUBES WITH DEFECTS;113
12.1;INTRODUCTION;113
12.2;SCATTERING THEORY APPROACH TO CONDUCTANCE;114
12.3;SCATTERING FROM A SIMPLE BARRIER IN A NANOTUBE;119
12.4;QUASIPARTICLE LIFETIME AND DENSITY OF STATES;123
12.5;LOCALIZATION LENGTH;126
12.6;CONCLUDING REMARKS;128
12.7;ACKNOWLEDGMENT;129
12.8;REFERENCES;129
13;PHYSICS OF THE METAL-CARBON NANOTUBE INTERFACES: CHARGE TRANSFERS, FERMI-LEVEL “PINNING” AND APPLICATION TO THE SCANNING TUNNELING SPECTROSCOPY;131
13.1;INTRODUCTION;131
13.2;METHODS;132
13.3;RESULTS;137
13.4;DISCUSSIONS AND CONCLUSIONS;141
13.5;ACKNOWLEDGMENT;143
13.6;REFERENCES;143
14;SINGLE PARTICLE TRANSPORT THROUGH CARBON NANOTUBE WIRES: EFFECT OF DEFECTS AND POLYHEDRAL CAP;146
14.1;INTRODUCTION;146
14.2;METHOD;147
14.3;DEFECTS;149
14.4;TRANSPORT THROUGH A POLYHEDRAL CAP;151
14.5;CONCLUSIONS;155
14.6;REFERENCES;157
15;CARBON NANOTUBES FROM OXIDE SOLID SOLUTION : A WAY TO COMPOSITE POWDERS, COMPOSITE MATERIALS AND ISOLATED NANOTUBES;159
15.1;INTRODUCTION;159
15.2;EXPERIMENTAL;160
15.3;RESULTS AND DISCUSSION;162
15.4;CONCLUSIONS;174
15.5;REFERENCES;175
16;IMPULSE HEATING AN INTERCALATED COMPOUND USING A 27.12 MHz ATMOSPHERIC INDUCTIVELY COUPLED ARGON PLASMA TO PRODUCE NANOTUBULAR STRUCTURES;177
16.1;INTRODUCTION;177
16.2;DISCUSSION AND RESULTS;181
16.3;THE FUTURE?;186
16.4;CONCLUSIONS;186
16.5;ACKNOWLEDGEMENTS;187
16.6;REFERENCES;187
17;THE SYNTHESIS OF SINGLE-WALLED CARBON NANOTUBES BY CVD CATALYZED WITH MESOPOROUS MCM-41 POWDER;189
17.1;INTRODUCTION;189
17.2;EXPERIMENTAL;190
17.3;RESULTS;191
17.4;CONCLUSIONS;200
17.5;ACKNOWLEDGEMENT;200
17.6;REFERENCE;200
18;MECHANICAL PROPERTIES AND ELECTRONIC TRANSPORT IN CARBON NANOTUBES;202
18.1;INTRODUCTION;202
18.2;MECHANICAL PROPERTIES;202
18.3;TRANSPORT PROPERTIES;206
18.4;SUMMARY AND CONCLUSIONS;207
18.5;REFERENCES;210
19;ELECTROCHEMICAL STORAGE OF HYDROGEN IN CARBON SINGLE WALL NANOTUBES;211
19.1;ABSTRACT;211
19.2;EXPERIMENTAL;211
19.3;CYCLIC STABILITY;213
19.4;CHARGE/DISCHARGE CURVES;215
19.5;CHEMICAL TREATMENT TO IMPROVE THE KINETIC PROPERTIES;215
19.6;CONCLUSIONS;219
19.7;REFERENCES;219
20;DIRECT MEASUREMENT OF BINDING ENERGY VIA ADSORPTION OF METHANE ON SWNT;220
20.1;ABSTRACT;220
20.2;INTRODUCTION;220
20.3;Experimental;221
20.4;BIBLIOGRAPHY;226
21;ELECTRICAL PROPERTIES OF CARBON NANOTUBES: SPECTROSCOPY, LOCALIZATION AND ELECTRICAL BREAKDOWN;227
21.1;INTRODUCTION;227
21.2;ELECTRICAL PROPERTIES OF SINGLE-WALLED NANOTUBES: NANOTUBE RINGS;228
21.3;ELECTRICAL TRANSPORT AND BREAKDOWN IN MULTI-WALLED TUBES;233
21.4;ELECTRICAL PROPERTIES OF SEMICONDUCTING NANOTUBES;235
21.5;REFERENCES;240
22;FIELD EMISSION OF CARBON NANOTUBES FROM VARIOUS TIP STRUCTURES;242
22.1;INTRODUCTION;242
22.2;MODEL SYSTEM AND COMPUTATIONAL METHOD;242
22.3;ELECTRONIC STRUCTURE OF MODEL SYSTEMS;243
22.4;EFFECT OF EXTERNAL FIELDS;244
22.5;LOCAL FIELD ENHANCEMENT;249
22.6;DISCUSSION;253
22.7;REFERENCES;254
23;FIRST AND SECOND-ORDER RESONANT RAMAN SPECTRA OF SINGLE-WALLED CARBON NANOTUBES;255
23.1;INTRODUCTION;255
23.2;1D DENSITY OF ELECTRONIC STATES;258
23.3;FIRST-ORDER STOKES SPECTRA;260
23.4;THE D-BAND AND G´ BAND FEATURES;263
23.5;OVERTONES AND COMBINATION MODES;268
23.6;SUMMARY;273
23.7;ACKNOWLEDGMENTS;275
23.8;REFERENCES;275
24;ON THE OVERLAP ENERGY IN CARBON NANOTUBES;277
24.1;INTRODUCTION;277
24.2;THEORETICAL ISSUES;277
24.3;RELEVANT EXPERIMENTAL RESULTS;287
24.4;STS/STM Measurements;288
24.5;Optical Measurements;288
24.6;Resonant Raman Scattering Experiments;289
24.7;Anti-Stokes Resonant Raman Spectra;291
24.8;THE ‘D-BAND’ DISPERSION EFFECTS;294
24.9;SUMMARY AND CONCLUSIONS;295
24.10;REFERENCES;296
25;ELECTRONIC AND MECHANICAL PROPERTIES OF CARBON NANOTUBES;298
25.1;INTRODUCTION;298
25.2;SAMPLES;298
25.3;MECHANICAL PROPERTIES;301
25.4;TRANSPORT PROPERTIES;305
25.5;ELECTRON SPIN RESONANCE;312
25.6;ELECTRON AND LIGHT EMISSION;315
25.7;ACKNOWLEDGEMENT;320
25.8;REFERENCES;320
26;LOW ENERGY THEORY FOR STM IMAGING OF CARBON NANOTUBES;322
26.1;ABSTRACT;322
26.2;INTRODUCTION;322
26.3;STM IMAGES: GENERAL THEORY;323
26.4;RESULTS FOR STM IMAGES OF CONDUCTING TUBES;326
26.5;IMAGE SWITCHING FOR SEMICONDUCTING TUBES;328
26.6;SUMMARY;330
26.7;ACKNOWLEDGMENTS;331
26.8;REFERENCES;331
27;QUANTUM TRANSPORT IN INHOMOGENEOUS MULTI-WALL NANOTUBES;333
27.1;INTRODUCTION;333
27.2;GENERAL SCATTERING TECHNIQUE;335
27.3;CONDUCTANCE IN MULTI-WALL NANOTUBES;338
27.4;TRANSPORT IN INHOMOGENEOUS MULTI-WALL NANOTUBES;342
27.5;CONCLUSIONS;346
27.6;ACKNOWLEDGEMENTS;346
27.7;REFERENCES;346
28;CONDUCTIVITY MEASUREMENTS OF CATALYTICALLY SYNTHESIZED CARBON NANOTUBES;348
28.1;ABSTRACT;348
28.2;INTRODUCTION;348
28.3;NANOTUBE SYNTHESIS;349
28.4;RESULTS AND DISCUSSION;349
28.5;CONCLUSIONS;352
28.6;ACKNOWLEDGEMENTS;352
28.7;REFERENCES;352
29;FABRICATION OF FULL-COLOR CARBON-NANOTUBES FIELD-EMISSION DISPLAYS: LARGE AREA, HIGH BRIGHTNESS, AND HIGH STABILITY;354
29.1;I. Introduction;354
29.2;II.Field Emission Display;354
29.3;III. Fabrication process of CNT-FED;356
29.4;IV. Emission properties of CNT-FED A. Imaging of emission site;358
29.5;C. Emission current-voltage characteristics;359
30;FREE SPACE CONSTRUCTION WITH CARBON NANOTUBES;364
30.1;ABSTRACT;364
30.2;INTRODUCTION;364
30.3;EXPERIMENTAL APPARATUS;365
30.4;EXPERIMENT;369
30.5;RESULTANT GEOMETRIES;373
30.6;CONCLUSIONS;374
30.7;ACKNOWLEDGEMENTS;376
30.8;REFERENCES;376
30.9;PARTICIPANTS;377
31;GLOSSARY OF COMMON ABBREVIATIONS;391
32;INDEX;392

Leseproben

PHYSICS OF THE METAL-CARBON NANOTUBE INTERFACES: CHARGE TRANSFERS, FERMI-LEVEL "PINNING" AND APPLICATION TO THE SCANNING TUNNELING SPECTROSCOPY (p. 121-122)

Yongqiang Xue1 and Supriyo Datta2
1 School of Electrical and Computer Engineering, Purdue University,
West Lafayette, IN 47907, USA
Email: [e-mail]
2 School of Electrical and Computer Engineering, Purdue University,
West Lafayette, IN 47907, USA
Email: [e-mail]

INTRODUCTION

After its discovery in 1991,1 carbon nanotube has rapidly emerged as the most promis-- ing candidate for molecular electronics due to its quasi-one dimensional structure and the unique characterization of its electronic structure in terms of two simple geometric indices.2 Besides its huge technological potential, carbon nanotube also serves as the artificial laboratory in which one-dimensional transport can be investigated,3 sim-- ilar to the semiconductor quantum wire.4 However, unlike its semiconductor cousin where transport is mostly ballistic, the study of transport in carbon nanotube has been distressed by the difficulty of making low resistance contact to the measuring electrodes. The high resistances reported in various two- and three-terminal measurements5 have led Tersoff6 (and also independently by one of the authors7) to suggest that wavevector conservation at the metal-carbon nanotube contact may play an important role in explaining the high contact resistance.8 The complexity and importance of the metal-carbon nanotube interface makes it an immediate challenge to both theorists and experimentalists.

The single most important property of the metal-carbon nanotube interface (and in general, of any interface involving metal) is the position of the energy bands (or energy levels) of the nanotube relative to the Fermi-level of the metal which manifests itself in the electronic transport property of the interface. Depending on the contact geometry, transport can occur in the direction parallel to the nanotube axis, in the case of the nanotube field-effect-transistor (FET),5,9 or perpendicular to it, in the case of the STS measurement.10,11 In the STS measurement, the Fermi-level is found to have shifted to the valence band edge of the semiconducting nanotube.10 Such observed Fermi-level "pinning" has been used to explain the operation of the nanotube FETs with highresistance contacts,5 where the measured two-terminal resistance for metallic nanotube is Recently low resistance contacts with two-terminal resistance as low as have been obtained.9 However, low temperature transport measurements using these low resistance contacts show that the Fermi-level is located between the valence and the conductance band of the semiconducting nanotube, instead of being "pinned" at the valence band edge. This conflict raises the important question of whether the Fermi-level positioning may depend on the contact geometry and the interface coupling. In this paper we present a theory of the scanning tunneling spectroscopy of a singlewall carbon nanotube (SWNT) supported on the Au(111) substrate.

The central idea is that the work function difference between the gold substrate and the nanotube leads to charge transfers across the interface, which induce a local electrostatic potential perturbation on the nanotube side. This atomic-scale interfacial potential perturbation shifts the energy level of the nanotube relative to the gold Fermi-level, and gives rise to the observed Fermi-level shift in the STS current-voltage characteristics. However, for transport in the direction parallel to the nanotube axis, as in the case of nanotube transistors, such local potential perturbation at the interface is not important in determining the Fermi-level position if the coupling between the metal and the nanotube is strong (i. e. , low resistance contact). In this case, the metal-induced gap states (MIGS) model provides a good starting point for determining the Fermi-level position. Based on this model, we expect that any discrepancy between the metal Fermi-level and the nanotube "charge-neutrality level" should be rapidly screened out by the metal-induced gap states in the nanotube side,12–14 leading to the "pinning" of the Fermi-level. Another important feature in our theory is that we have taken into account the localized 5d orbitals of the platinum tip in our treatment of the STS which can have significant effects on the interpretation of the STS data.15 Our discussion is restricted to the low temperature regime, in correspondence with the experimental works.

METHODS

A convenient way of characterizing the band lineup problem at any interface is to find a reference level, the role of which is to put all materials forming the interface on a common absolute energy scale.13,14 If the position of the reference level depends only on the bulk property, then the relative position of the energy bands at the interface can be determined trivially by merely lining up the reference levels. This is the elegant idea of "charge-neutrality level",12 which has been applied with impressive success by Tersoff13,14 to various metal-semiconductor junctions and semiconductor heterojunctions. For metal, the reference level is the Fermi-level while for semiconductor, it is the so called "charge-neutrality level" which can be taken as the energy where the gap states cross over from valence- to conduction-band character.

This approach greatly simplifies the band lineup problem and gives quantitatively accurate prediction of the Schottky barrier height when applied to the metalsemiconductor interface.13 The success of this model relies on the fact that there exists a continuum of gap states around at the semiconductor side of the metalsemiconductor interface due to the tails of the metal wavefunction decaying into the semiconductor, which can have significant amplitude a few atomic layers away from the interface.12 Any deviation from the local charge neutrality condition in the interface region will be screened out rapidly by these metal-induced gap states (MIGS). In this way, the local charge and potential perturbations right at the interface are not important in determining the barrier height observed in the transport characteristics since the range of this local perturbation is only a few atomic layers, and the charge carriers can easily tunnel through this region.