PHOTOELECTRO-IONIC PROCESSES IN PHOTOINDUCED SURFACE DEPOSITION OF METALLIC SILVER ON A CHALCOGENIDE GLASS

To understand the mechanism of Ag+ migration in the phenomenon of phot oinduced surface deposition (PSD) of metallic silver, the photoelectro -ionic properties of glasses showing the PSD phenomenon have been stud ied using Ag-rich Ag-As-S glasses. From the Dember and photovoltaic ef fects of the glasses, it is suggested that the glasses are p-type semi conductors and that the photoexcited electrons can be trapped by the A g particles deposited by the PSD phenomenon, The depth profile of the Ag concentration after photodeposition was examined by electron-probe microanalysis to determine the consumption of Ag at the illuminated su rface. The profile was found to be almost constant from the illuminate d surface to the deep interior of the glass, suggesting that Ag+ ions deeper than 1 mu m can migrate in counterflow to the hole motion. Acco rdingly, Ag+ migration in the PSD phenomenon can be accounted for both by the Coulomb force induced by the trapped electrons and coupled ion -hole motions deep inside the glass.