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

Raman spectra of single-wall carbon nanotubes (SWCNTs) were measured at different temperatures by varying the incident laser power. The elevated temperature of the SWCNTs and multiwall carbon nanotubes (MWCNTs) is confirmed to be due to the presence of impurities, defects, and disorder. The temperature coefficient of the frequency of the C-C stretching mode E-2g (GM) and that 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 attributed 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].