Role of samarium atoms in the formation of the structure of As–Se–S chalcogenide vitreous semiconductors

The Raman spectra of films of samarium-doped As–Se–S three-component chalcogenide vitreous semiconductors are studied. It is shown that the spectra are constituted by four bands in the frequency ranges 10–100, 195–290, 290–404, and 420–507 cm$^{-1}$, which strongly vary with doping. The structural units in As–Se–S and their possible changes upon doping are determined. The results obtained are accounted for by the specific distribution of samarium atoms in the sample and by their chemical activity.