TY - JOUR AU - Pop, M.M. AU - Studenyak, V.I. AU - Pogodin, A.I. AU - Kokhan, O.P. AU - Suslikov, L.M. AU - Studenyak, I.P. AU - Kúš, P. PY - 2021/05/28 Y2 - 2024/03/28 TI - Optical Properties of Cation-Substituted (Cu1 – xAgx)7GeSe5I Mixed Crystals JF - Ukrainian Journal of Physics JA - Ukr. J. Phys. VL - 66 IS - 5 SE - Semiconductors and dielectrics DO - 10.15407/ujpe66.5.406 UR - https://ujp.bitp.kiev.ua/index.php/ujp/article/view/2020130 SP - 406 AB - <p>(Cu<sub>1−x</sub>Ag<sub>x</sub>)<sub>7</sub>GeSe<sub>5</sub>I mixed crystals were grown by the vertical zone crystallization method and are shown to crystallize in a cubic structure (F43m). The diff use reflection spectra for the powders of (Cu<sub>1−x</sub>Ag<sub>x</sub>)<sub>7</sub>GeSe<sub>5</sub>I mixed crystals were measured at room temperature. The refractive indices and extinction coefficients for (Cu<sub>1−x</sub>Ag<sub>x</sub>)<sub>7</sub>GeSe<sub>5</sub>I mixed crystals were obtained from spectral ellipsometry measurements. Two anomalies of the refractive index in the spectral region from 440 nm to 1000 nm are observed. One of them corresponds to the band-to-band optical transition, while another one to the interband Van Hove–Phillips singularity. A nonlinear decrease of the energy pseudogap is revealed with an increase in the Ag content in (Cu<sub>1−x</sub>Ag<sub>x</sub>)<sub>7</sub>GeSe<sub>5</sub>I mixed crystals.</p> ER -