Raman study of the high-pressure hydrogenated single-wall carbon nanotubes: In search of chemically bonded and adsorbed molecular hydrogen

Hydrogenated single-wall carbon nanotubes (SWNT) were investigated by micro-Raman spectroscopy. The main feature of the Raman spectrum is a giant structureless hot luminescence background that screens all vibrational modes. This disorder-induced background vanishes after annealing in vacuum or in air. The changes in the Raman spectra of the partially annealed samples reflect the gradual elimination of structural disorder, related to removal of randomly bonded hydrogen. Complete outgassing restores the characteristic Raman spectrum of the pristine SWNT.