Photodissolution of Silver in AmorphousAs2S3Films

Analysis of published spectral data shows that the photons relevant to photodissolution of metals in amorphous chalcogenide semiconductors are absorbed in the metal and not in the semiconductor. It is argued that light does not enhance the diffusion of metal atoms in the chalcogenide matrix, but triggers a solid-state chemical reaction at the metal-semiconductor interface. A new amorphous phase in the Ag-As-S system, ${\mathrm{As}}_4$ ${\mathrm{Ag}}_5$ ${\mathrm{S}}_6$, is postulated to explain the peculiar physical and chemical properties of the new photogenerated material.