Mechanism of photoinduced changes in the structure and optical properties of amorphous As2S3

We propose a mechanism of photostructural changes in amorphous As2S3 ( a-As2S3) on the basis of ab initio molecular orbital calculations on clusters of atoms modeling the local structure of the amorphous system. We have found that trigonal AsS3 pyramidal units can be transformed into a fivefold coor...

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Bibliographic Details
Published inPhysical review letters Vol. 85; no. 15; p. 3305
Main Authors Uchino, T, Clary, D C, Elliott, S R
Format Journal Article
LanguageEnglish
Published United States 09.10.2000
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Summary:We propose a mechanism of photostructural changes in amorphous As2S3 ( a-As2S3) on the basis of ab initio molecular orbital calculations on clusters of atoms modeling the local structure of the amorphous system. We have found that trigonal AsS3 pyramidal units can be transformed into a fivefold coordinated As site having four As-S bonds and one As-As bond via a photoionization process. This photoinduced coordination defect center exhibits a lower photoabsorption energy as compared with the usual pyramidal structure, explaining the observed photodarkening effect of a-As2S3.
ISSN:0031-9007
DOI:10.1103/PhysRevLett.85.3305