Photoinduced effects in amorphous chalcogenide films by vacuum ultra-violet light

Photoinduced effects in amorphous As2S3 films have been investigated by using a quasi-monochromatic undulator-radiation from an electron storage-ring as a vacuum ultra-violet light source. On irradiation, the optical absorption edge shifts to lower energies. This change is similar to the photodarkening phenomena with irradiation of bandgap light and is returned to the original state by annealing near the glass-transition temperature. However, the rate of photodarkening excited with the vacuum ultra-violet light is two orders of magnitude higher than that with the bandgap light under the same photon number.