Temperature dependence of the Raman spectra of single-wall carbon nanotubes

Raman spectra of single-wall carbon nanotubes (SWCNTs) were measured at dif ferent temperatures by varying the incident laser power. The elevated tempe rature of the SWCNTs and multiwall carbon nanotubes (MWCNTs) is confirmed t o be due to the presence of impurities, defects, and disorder. The temperat ure coefficient of the frequency of the C-C stretching mode E-2g (GM) and t hat of the radial breathing mode in the SWCNT were determined to be similar to-0.038 and similar to-0.013 cm(-1)/K, respectively. It is found that the temperature coefficient of the GM in the SWCNT is larger than that of the MWCNT, highly oriented pyrolytic graphite, and the graphite. This is attrib uted to the structural characteristic of the SWCNT-a single tubular carbon sheet with smaller diameter. (C) 2000 American Institute of Physics. [S0003 -6951(00)04615-5].