Comparison of reversible photodarkening in As2S3 and As2Se3 amorphous thin films
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Photoinduced darkening of well annealed amorphous As2S3 and As2Se3 films induced by exposure to near-band gap monochromatic light with various intensities was studied. Under well comparable conditions of exposure the magnitude of photodarkening of As2S3 exceeds the one of As2Se3. In both cases, the kinetics of photoinduced darkening follows single exponential and the formal rate constant of photodarkening of As2S3 was found almost one order magnitude higher compared to As2Se3. Exposure by medium and high intensities enhances the red shift of the gap. This enhancement is, however, unstable and can be erased either by a dark relaxation or by illumination using the same near-band gap monochromatic light with low intensity. Observed differences in photodarkening of As2S3 and As2Se3 thin films are briefly discussed.
KeywordsChalcogenide Glass As2Se3 Average Coordination Number Photoinduced Change Incident Photon Flux
Supported by the project MSMT 1K05012. L.T. also acknowledges support from the project AVOZ 40500505.
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