Wavelength Dependence of Photostructural Transformations in As2S3 Thin Films

Spectral dependence of photostructural transformations on the surface and in the interior of thermally evaporated As2S3 thin films is studied under the influence of bandgap, sub-bandgap and super-bandgap light. For the given light intensity (W~15 mW/cm2) the irradiation by bandgap and super-bandgap light leads to partial restoration of pyramidal structural units in the film, which is a characteristic of the bulk glasses of this stoichiometric composition. The mechanism of photostructural transformations on the surface of the film exhibits strong spectral dependence. S- rich layer is formed upon irradiation by super-bandgap UV light. The sub-bandgap light does not cause any noticeable photostructural transformations at this light intensity.