Single-walled carbon nanotubes (SWNTs) offer the prospect of both new fundamental science and useful (nano)technological applications1. High yields (70–90%) of SWNTs close-packed in bundles can be produced by laser ablation of carbon targets2. The electric-arc technique used to generate fullerenes and multi-walled nanotubes is cheaper and easier to implement, but previously has led to only low yields of SWNTs3,4. Here we show that this technique can generate large quantities of SWNTs with similar characteristics to those obtained by laser ablation. This suggests that the (still unknown) growth mechanism for SWNTs must be independent of the details of the technique used to make them. The ready availability of large amounts of SWNTs, meanwhile, should make them much more accessible for further study.

Large-scale production of single-walled carbon nanotubes by the electric-arc technique

Single wall carbon nanotubes (SWNTs) that are found as close-packed arrays in crystalline ropes have been studied by using Raman scattering techniques with laser excitation wavelengths in the range from 514.5 to 1320 nanometers. Numerous Raman peaks were observed and identified with vibrational modes of armchair symmetry (n, n) SWNTs. The Raman spectra are in good agreement with lattice dynamics calculations based on C-C force constants used to fit the two-dimensional, experimental phonon dispersion of a single graphene sheet. Calculated intensities from a nonresonant, bond polarizability model optimized for sp2 carbon are also in qualitative agreement with the Raman data, although a resonant Raman scattering process is also taking place. This resonance results from the one-dimensional quantum confinement of the electrons in the nanotube.

https://science.sciencemag.org/content/sci/275/5297/187.full.pdf

Diameter-Selective Raman Scattering from Vibrational Modes in Carbon Nanotubes

Carbon nanotubes are unique tubular structures of nanometer diameter and large length/diameter ratio. The nanotubes may consist of one up to tens and hundreds of concentric shells of carbons with adjacent shells separation of ∼0.34 nm. The carbon network of the shells is closely related to the honeycomb arrangement of the carbon atoms in the graphite sheets. The amazing mechanical and electronic properties of the nanotubes stem in their quasi-one-dimensional (1D) structure and the graphite-like arrangement of the carbon atoms in the shells. Thus, the nanotubes have high Young’s modulus and tensile strength, which makes them preferable for composite materials with improved mechanical properties. The nanotubes can be metallic or semiconducting depending on their structural parameters. This opens the ways for application of the nanotubes as central elements in electronic devices including field-effect transistors (FET), single-electron transistors and rectifying diodes. Possibilities for using of the nanotubes as high-capacity hydrogen storage media were also considered. This report is intended to summarize some of the major achievements in the field of the carbon nanotube research both experimental and theoretical in connection with the possible industrial applications of the nanotubes.

Carbon nanotubes: properties and application

The Element Carbon Frank Hennrich, Valerie Moore, Marco Rolandi, and Mike O'Connell Allotropes of Carbon History Structure Progress of Single-Walled Carbon Nanotube Research toward Application References Synthesis of Carbon Nanotubes David Mann Introduction CNT Synthesis Methods Overview Specifics of CVD Growth Method Recent Advances in SWCNT Growth Control Conclusion References Carbon Nanotube Peapod Materials Satishkumar B. Chikkannanavar, Brian W. Smith, and David E. Luzzi Introduction and Historical Perspective C60@SWNT Beyond C60: Other Hierarchical Nanotube Materials Ordered Phases of Fullerenes in Larger Nanotubes Double-Wall Carbon Nanotubes Conclusions and Future Prospects Acknowledgments References Carbon Nanotube Electronics and Devices Marcus Freitag Metallic Carbon Nanotubes Semiconducting Carbon Nanotubes Outlook and Challenges References Magnetic Properties Junichiro Kono and Stephan Roche Introduction Theoretical Perspectives Experimental Results Acknowledgments References Raman Spectroscopy of Single-Walled Carbon Nanotubes: Probing Electronic and Chemical Behavior Stephen K. Doorn, Daniel Heller, Monica Usrey, Paul Barone, and Michael S. Strano Introduction Resonance Raman Studies of Carbon Nanotubes Raman Characterization of Nanotube Samples and Nanotube Reactivity Conclusions References Electromechanical Properties and Applications of Carbon Nanotubes Randal J. Grow Introduction Piezoresistance Theory of Strain-Induced Band-Gap Changes in Carbon Nanotubes Electrical Measurements of Strain-Induced Band-Gap Changes in Suspended Tubes Electrical Measurements of Strain-Induced Band-Gap Changes in Tubes on a Surface Conclusion of Piezoresistance of Nanotubes Electrostatic actuation Nanoelectromechanical systems Conclusion References Carbon Nanotube-Enabled Materials Han Gi Chae, Jing Liu, and Satish Kumar Introduction Dispersion and Processing Issues Characterization of Polymer/CNT Composites CNT Films and Fibers Polymer/CNT Composite Films and Fibers Crystallization, Wrapping, Interaction, and Intercalation Concluding Remarks Acknowledgment References Functionalized Carbon Nanotubes in Composites Christopher A. Dyke and James M. Tour Introduction SWNT Preparation and Characterization Functionalized SWNTs Carbon Nanotube-Modified Composites Conclusions Acknowledgments References Carbon Nanotube Tips for Scanning Probe Microscopy C. Patrick Collier Carbon nanotubes as AFM probes Fabrication of nanotube probe tips AFM imaging with nanotube probes Applications of carbon nanotube probes Future directions Acknowledgments References Index

Carbon Nanotubes: Properties and Applications

Physics of carbon nanotubes

Vibrational modes of carbon nanotubes; Spectroscopy and theory

Experimental and theoretical studies of the vibrational modes of carbon nanotubes are reviewed. The closing of a 2D graphene sheet into a tubule is found to lead to several new infrared (IR)- and Raman-active modes. The number of these modes is found to depend on the tubule symmetry and not on the diameter. Their diameter-dependent frequencies are calculated using a zone-folding model. Results of Raman scattering studies on arc-derived carbons containing nested or single-wall nanotubes are discussed. They are compared to theory and to that observed for other sp2 carbons also present in the sample.

R.A. Jishi

Papers

Vibrational modes of carbon nanotubes; Spectroscopy and theory

Vibrational modes of carbon nanotubes; spectroscopy and theory