Of particular importance is the uniqueness of the electronic transition energies for each nanotube, which are described in terms of two integers (n, m) which uniquely specify the geometrical structure of the nanotube, including its diameter and chirality. However, at the single nanotube level, the characteristics of each feature can be studied in detail, including its dependence on diameter, chirality, laser excitation energy and closeness to resonance with electronic transitions. All Raman features normally observed in single wall nanotube (SWNT) bundles are also observed in spectra at the single nanotube level, including the radial breathing mode, the G-band, the D-band and the G’-band. This work eventually led to the observation of Raman spectra from one single nanotube, with intensities under good resonance conditions comparable to that from the silicon substrate, even though the ratio of carbon to silicon atoms in the light beam was approximately only one carbon atom to one hundred million silicon atoms. Next we showed characteristic differences between the Raman profile of the G-band depending on whether the nanotubes were metallic or semiconducting. at the University of Kentucky in 1997) of the Raman spectra from bundles of single wall carbon nanotubes and showing a strong enhancement of the spectra through a diameter selective resonance Raman effect. This work started in earnest with the initial observation (with Rao et al. Regarding carbon nanotubes, which were previously predicted to be either semiconducting or metallic depending on their geometries, we have been developing the method of Raman spectroscopy as a sensitive tool for the characterization of single wall carbon nanotubes, one atomic layer in wall thickness. Recent research activities in the Dresselhaus group that have attracted wide attention are in the areas of carbon nanotubes, bismuth nanowires and low dimensional thermoelectricty.
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Extended Abstracts, EA -8, Pittsburgh, PA 1986). Graphite Intercalation Compounds, edited by M.S. Extended Abstracts, EA -2, Pittsburgh, PA 1984). Graphite Intercalation Compounds, edited by P. Dresselhaus (Plenum Press, New York, 1987), Vol. Intercalation in Layered Materials, edited by M.S.
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