Influence of preparation conditions on photo- and thermo-structural changes of AsxS1−x films

Photo- and thermo-structural changes occuring in vaccum-deposited amorphous chalcogenide films prepared by different methods have been investigated using Raman scattering. The changes in the Raman spectra of conventionally prepared amorphous As2S3 films after light treatment are interpreted in terms of rearrangement of bonding configurations of molecular species that exist just after evaporation. As the evaporation temperature or deposition rate is increased, heat or light treatment induces the formation of microcrystallites. The reversible photo-induced changes in well-annealed films involve a vanishingly small change in bonding statistics. The most significant photostructural change occurs in the medium-range order.