Optical spectra of TlGaS2 crystals

Wavelength modulated reflection spectra measured at temperatures 14 K and 300 K in E||a and E||b polarizations for TlGaS2 crystals were investigated. The ground and excited states of excitons B2u in E||a polarization and B3u in E||b polarization were observed and the main parameters of exitons and bands were determined. The optical functions for wide energies (2-6 eV) were calculated by Kramers-Kronig analysis of reflection spectra. The wavelengths of isotropic points in TlGaS2 crystals were defined.