OPTICAL MATERIALS, cilt.84, ss.94-98, 2018 (SCI-Expanded)
Transmittance on TlGaxIn1-xS2 mixed crystals (0 <= x <= 1) was carried out in the 2.35-2.75 eV photon energy range at T = 10 K. Band gap energies of crystals were obtained utilizing the derivative spectra of transmittance and photon energy dependence of absorption coefficient. The dependence of direct band gap energy on composition at T = 10 K revealed that as gallium composition is elevated in the mixed crystals, the direct band gap energy increases from 2.56 to 2.67 eV.