XPS study of Au+ ion irradiated a-As2S3 layers

The changes in the solubility of a-As2S3 evaporated layers under Au+ ion irradiation occur in a greater depth than the ion penetration range calculated by the TRIM program. An XPS analysis was made to elucidate the phenomenon. Surface and depth distributions of implanted ions, as well of As and S were examined and it was established that under implantation the binding energy (BE) for the Au 4f(7/2) peak shifts by 0.65 eV when compared to the sputtered Au standard (83.9 eV). Increase in the concentration of implanted Au+ ions led to the appearance of peaks at both 84.55 and 85.35 eV. It was found out that the shift of BE of S 2p depended on the concentration of implanted Au+ ions, while the BE of As 3d was nearly the same. On the basis of these results the effects of Au irradiation are discussed. (C) 1998 Elsevier Science Ltd. All rights reserved.