POLARIZED-LIGHT SPECTRA OF TL3SBS3 SINGLE-CRYSTALS

An investigation was made of the polarized-light absorption and photoconductivity spectra of Tl3SbS3 semiconductors in the fundamental absorption region, and also of the reflection spectra in the photon energy range from 1.5 to 6.0 eV. These spectra demonstrated that the width of the band gap was anisotropic and it amounted to 1.48 and 1.65 eV for the E perpendicular-to c and E parallel-to c directions, respectively. The temperature dependences were used to separate the exciton resonances. The Kramers-Kronig relationships were employed in a calculation of the spectra of the real epsilon-1(E) and imaginary epsilon-2(E) parts of the permittivity, which was necessary in determination of the relationship between the parameters of the electron structure (gaps between the bands) and the optical spectra. A qualitative interpretation of the optical spectra was provided.