Spectroscopy of atom movements in photo-excited silver-chalcogenide glasses

Absorption current imaging and scanning tunneling spectroscopy (STS) measurements were performed to study the electrical properties of partially photo-exposed silver-selenide (Ag2Se) surface. The absorption current images reveal photo-increased conductance, revealing a newly formed Ag layer. The time-resolved STS studies clarify the dynamical aspects of Ag+ ion movement and photo-induced change in the electronic structure of the surface; from semiconductor to metal on the exposed regions and from semiconductor to semiinsulator on the unexposed ones. These phenomena resulting from photo-induced Ag movement verify that photo-fixed Ag clusters and movable Ag+ ions exist in conflict with each other on the exposed surface. 15 refs.