THE MECHANISM OF PHOTOINDUCED TRANSFORMATIONS IN AMORPHOUS AS(2)S(3) THIN-FILMS

Physical photographic development is applied for visualization of the photoinduced transformations in amorphous As2S3 thin films. It is esta blished that, in comparatively narrow exposure interval, the samples s tudied show a negative photographic response. The latter is explained by the formation of a latent image capable of initiating the developme nt process. Simultaneously, similar catalytic activity of As clusters, vacuum deposited on the surface of As2S3 films, is found. On this bas is, metal As is regarded as a constituting element of the latent image built up on illumination. Further, a quantitative evaluation of the p hotographic response is made. Thus, a higher efficiency of As cluster formation in the volume of the films as compared with the surface is f ound. Besides, a reduced photographic sensitivity of As2S3 films after annealing procedure is established. The results obtained are discusse d in terms of the model for light-induced phase separation in arsenic chalcogenides.