Temperature-dependent vibrational spectra of carbon nanotubes
Résumé
The complete Raman spectra of carbon tubules at various temperatures are compared with those of graphite and fullerene C60. The band at 1470 cm-1 as well as those in the range 100-600 cm-1 in tubules attest to the presence of pentagon-containing hemispherical surfaces on both the end caps and the inside terminations of the cylindrical structures of nanotubes. Raman microspectroscopy is also used to observe a temperature-dependent and reversible shift of the stretching frequencies corresponding to changes in the carbon-carbon distances in tubules. This could result in a temperature dependence of the diameters of the multilayer carbon nanotubes and could ultimately lead to a tuning method for structure-sensitive properties, such as the band gaps of individual tubes.