Photo-induced interdiffusion was observed with above band gap light in nano-layered Se/As2S3 films. It was analyzed in terms of the optical parameters such as band gap, Urbach edge (Ee) and B1/2 (Tauc’s parameter). Experimental data of B1/2 and Ee for as-prepared samples do not showed clear correlation implied by the Mott-Davis model. It was also shown that the optical parameters could be changed with a change in the Se sub-layer thickness. Variations of these optical parameters as a function of modulation period and photo-induced interdiffusion were considered in terms of the quantum confinement effect and changes in the valence and conduction bands. A model was proposed, in order to explain the mechanism of Se diffusion in As2S3, which suggested that diffusion took place through the wrong bonds. X-ray photo-electron microscopy was used to investigate the chemical alternations in the bonding. The proposed model was supported by the X-ray photo-electron spectroscopy data.

Photo-Induced Interdiffusion in Nanolayered Se/As2S3 Films - Optical and X-Ray Photo-Electron Spectroscopic Studies. K.V.Adarsh, K.S.Sangunni, T.Shripathi, S.Kokenyesi, M.Shipljak: Journal of Applied Physics, 2006, 99[9], 094301 (6pp)