Origin of photoinduced defects in glassy As2S3 under band gap illumination studied by Raman scattering: A revisory approach

Authors

  • S. N. Yannopoulos,

    Corresponding author
    1. Foundation for Research and Technology, Hellas Institute of Chemical Engineering Sciences (FORTH-ICE/HT), P.O. Box 1414, 26504, Rio-Patras, Greece
    • Phone: +30 2610 965252, Fax: +30 2610 965223
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  • K. S. Andrikopoulos,

    1. Foundation for Research and Technology, Hellas Institute of Chemical Engineering Sciences (FORTH-ICE/HT), P.O. Box 1414, 26504, Rio-Patras, Greece
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  • D. Th. Kastrissios,

    1. Foundation for Research and Technology, Hellas Institute of Chemical Engineering Sciences (FORTH-ICE/HT), P.O. Box 1414, 26504, Rio-Patras, Greece
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  • G. N. Papatheodorou

    1. Foundation for Research and Technology, Hellas Institute of Chemical Engineering Sciences (FORTH-ICE/HT), P.O. Box 1414, 26504, Rio-Patras, Greece
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  • Dedicated to Stanford R. Ovshinsky on the occasion of his 90th birthday

Abstract

We report on a detailed study of the photostructural changes in bulk glassy As2S3 under vacuum using Raman scattering. Various excitation energies were employed to achieve resonance and off-resonance conditions. Temperature-induced structural changes were also investigated at conditions far from resonance, in order to clarify the role of bandgap light on the induced structural changes. Bandgap illumination induces structural changes much stronger than those reported up to now for this glass. The absence of oxygen is considered as a possible cause of this observation. The kinetics of the structural changes was monitored in the course of bandgap illumination and the role of in situ annealing was considered. The formation of As–As bonds is the main light-induced structural change, which if contemplated together with the absence of S–S bond formation points to the failure of models adopting realgar-type structures and calls for new structural defects based on centers with increased coordination number. The vibrational features of few such defects based on over-coordinated As centers are discussed in conjunction with the present experimental findings.

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