caa a22 4500 38802030X CHVBK 20180307124922.0 cr unu---uuuuu 161130e199809 xx s 000 0 eng 10.1557/JMR.1998.0333 doi S0884291400045702 pii (NATIONALLICENCE)cambridge-10.1557/JMR.1998.0333 Raman Scattering Study of Coalesced Single Walled Carbon Nanotubes [Elektronische Daten] High temperature heat treatment of single wall carbon nanotube bundles in flowing H2 was used to produce a significant fraction (∼40%) of diameter-doubled, or coalesced tubes with a mean diameter corresponding to that of ∼(20, 20) tubes. At three laser excitation wavelengths (514.5, 647, and 1064 nm), a reduction in the Raman scattering intensity of the strong radial and tangential modes was observed in the H2-treated sample, consistent with the reduced fraction of tubes in the sample after coalescence. However, using 488 nm excitation, little or no change is observed in the Raman spectrum after the H2 treatment, suggesting that this excitation wavelength couples only to chiral symmetry tubes. Using the 647 nm excitation, the effect of H2 treatment on the tangential band is quite unique, and a significant change in the shape of the tangential band was observed. Our lineshape analysis, and other results reported in this issue, suggest that this unique change of shape is due to lost scattering intensity from metallic tubes partially compensated by tangential mode scattering from the coalesced tubes. The normally prominent radial breathing mode band, which would be expected at ∼90 cm−1 for ∼(20, 20) tubes was not observed, indicating that these larger diameter tubes do not exhibit strong resonant scattering, at least at any of the wavelengths used in this study. Copyright © Materials Research Society 1998 Fang S. L. Department of Physics and Astronomy and Center for Applied Energy Research, University of Kentucky, Lexington, Kentucky 40506 Rao A. M. Department of Physics and Astronomy and Center for Applied Energy Research, University of Kentucky, Lexington, Kentucky 40506 Eklund P. C. Department of Physics and Astronomy and Center for Applied Energy Research, University of Kentucky, Lexington, Kentucky 40506 Nikolaev P. Center for Nanoscale Science and Technology, Rice Quantum Institute, and Departments of Chemistry and Physics, Rice University, Houston, Texas 77251 Rinzler A. G. Center for Nanoscale Science and Technology, Rice Quantum Institute, and Departments of Chemistry and Physics, Rice University, Houston, Texas 77251 Smalley R. E. Center for Nanoscale Science and Technology, Rice Quantum Institute, and Departments of Chemistry and Physics, Rice University, Houston, Texas 77251 Journal of Materials Research Cambridge University Press 13/9(1998-09), 2405-2411 0884-2914 13:9<2405 1998 13 JMR https://doi.org/10.1557/JMR.1998.0333 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1557/JMR.1998.0333 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Fang S. L. Department of Physics and Astronomy and Center for Applied Energy Research, University of Kentucky, Lexington, Kentucky 40506 NATIONALLICENCE 700 1- Rao A. M. Department of Physics and Astronomy and Center for Applied Energy Research, University of Kentucky, Lexington, Kentucky 40506 NATIONALLICENCE 700 1- Eklund P. C. Department of Physics and Astronomy and Center for Applied Energy Research, University of Kentucky, Lexington, Kentucky 40506 NATIONALLICENCE 700 1- Nikolaev P. Center for Nanoscale Science and Technology, Rice Quantum Institute, and Departments of Chemistry and Physics, Rice University, Houston, Texas 77251 NATIONALLICENCE 700 1- Rinzler A. G. Center for Nanoscale Science and Technology, Rice Quantum Institute, and Departments of Chemistry and Physics, Rice University, Houston, Texas 77251 NATIONALLICENCE 700 1- Smalley R. E. Center for Nanoscale Science and Technology, Rice Quantum Institute, and Departments of Chemistry and Physics, Rice University, Houston, Texas 77251 NATIONALLICENCE 773 0- Journal of Materials Research Cambridge University Press 13/9(1998-09), 2405-2411 0884-2914 13:9<2405 1998 13 JMR CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge