Raman investigation of reversible photoinduced effects in semiconducting Ge-S-Ga thin-film glasses

Publisher Website
Google Scholar
Abstract
Changes in the optical transparency and local structure, induced by exposure to band-gap light and/or annealing at temperatures below the glass-transition temperature Tg, have been observed in amorphous Ge-S-Ga thin films by measuring their transmission and Raman spectra. Either of the treatments leads to a bleaching effect accompanied by an increase of ordering in the local structure. In the combined treatment, photoexposure of previously annealed films results in (i) a further increase of ordering for annealing temperatures Tan up to a critical temperature Tc about 100 °C below Tg and (ii) a photodarkening effect and decrease of ordering for Tan >Tc . These results raise the possibility of using such films as base materials for the production of both negative and positive photoresists.