Structure of pulsed-laser deposited arsenic-rich As–S amorphous thin films, and effect of light and temperature

Thin amorphous films from As–S system (∼As50S50) were prepared by the pulsed laser deposition technique. Light- and thermally-induced changes of structure of studied films have been investigated using Raman scattering spectroscopy results and interpreted in terms of chemical reactions and/or phase transitions between individual structural units. The irradiation of as-deposited thin films causes light-induced reactions, in which As4S3, α- and β-As4S4, and pararealgar/χ-As4S4 molecules are formed. Thermal-annealing of exposed thin films leads to the formation of β-As4S4 molecules.