Concentration dependence of the optical properties of glassy alloys in the HgS-Ga2S3-GeS2 system

Abstract

The concentration dependences of the optical properties of glassy alloys in the HgS-Ga₂S₃-GeS₂ system have been investigated in the spectral range 2.0–2.9 eV. The energy gap E _g of glasses has been estimated, and the dependence of the energy gap on the content of HgS and Ga₂S₃ has been analyzed. The spectral dependences α(hν) for glasses in the system under investigation in the fundamental absorption range are described by the Urbach rule. The alloys containing ≥ 20 mol % (HgS + Ga₂S₃) are characterized by an ordering and a decrease in the energy gap E _g , which are explained by the changes in the short-range order in the arrangement of the atoms involved in the composition of alloys. It has been assumed that, at high concentrations of modifiers, there can arise microscopic inclusions, i.e., different defects, which can scatter light and decrease the transparency of glassy alloys.