Spectroscopic analysis of single-wall carbon nanotubes and carbon nanotube peapods

Raman spectra have been demonstrated repeatedly to be a very valuable tool for the analysis of new carbon phases such as fullerenes and single wall carbon nanotubes (SWCNTs). Recently it was demonstrated from TEM analysis that C-60 can be encapsulated into SWCNTs. The structures have been given the name 'peapods'. The concentration of the encapsulated 'peas' and the bonding structure in the tube are still unknown but under heavy discussion. From experience with C-60 and SWCNTs, Raman spectroscopy is expected to be a key technique for the analysis of such structures. In our experiments, we found two modes in the region of the pentagonal pinch mode of C-60. The resonance behavior for these two modes and their temperature dependence is shown in this paper. (C) 2002 Elsevier Science B.V. All rights reserved.