The reflectivity spectra of some group VA transition metal dichalcogenides

Abstract

Reflectivity spectra from the basal planes of crystals of 2H-NbSe2, 2H-TaSe2, 2H-TaS2 and 1T-TaS2 have been measured in the energy range 25 meV to 14 eV at room temperature and liquid nitrogen temperature. Using extrapolations of the experimental data to 0 eV and 30 eV, a Kramers-Kronig analysis of the data has been performed. The optical data so obtained has been discussed and interpreted in terms of the proposed band model for these materials.