@article{Pogodin2024280,
  title = {Particularities of optical behavior of Ag 8 SiS 6 single crystal},
  author = {A.I. Pogodin and I.O. Shender and M.M. Pop and M.J. Filep and T.O. Malakhovska and O.P. Kokhan and V.Yu. Izai and R. Mariychuk},
  journal = {Semiconductor Physics, Quantum Electronics & Optoelectronics},
  year = {2024},
  volume = {27},
  number = {3},
  pages = {280-286},
  doi = {10.15407/spqeo27.03.280},
  keywords = {argyrodite, single crystal, optical absorption edge, Urbach’s rule},
  abstract = {Ag8SiS6 single crystal was grown by directional crystallization from melt. A crystal sample was investigated by optical ellipsometry and spectroscopy. This sample had nonlinear spectral dependences of the refractive index n and the extinction coefficient k. The presence of a sharp maximum in the spectral dependence of the refractive index and a rather sharp decrease in the values of the extinction coefficient k at the wavelength of 780 nm were found. The behavior of the optical absorption edge of the Ag8SiS6 single crystal in the temperature range of 77…300 K was studied. An exponential dependence of the absorption coefficient α obeying the Urbach rule was observed at all the investigated temperatures. The optical pseudo-gap Eg* and the Urbach energy EU were calculated from the obtained experimental data. An increase in temperature of the Ag8SiS6 crystal was found to lead to a monotonic, almost linear decrease in Eg* (1.853…1.615 eV) and a monotonic nonlinear increase in EU (44.32…55.01 meV). The contributions of the temperature-independent (EU)X,C and temperature-dependent (EU)T components to the total Urbach energy EU for Ag8SiS6 were evaluated within the Einstein model.},
}