As4S4 role on the photoinduced birefringence of silver-doped chalcogenide thin films

Abstract

AgX(As40S60)100-X thin films (x = 7, 15, 25, 50) were deposited on glass slides by a co-evaporation technique under a vacuum. Photoinduced birefringence was induced using light provided from a continuous argon-ion laser operating at 488 nm. We investigated the impact of silver concentration and laser power density. The thin films structural changes after irradiation were characterized by Raman spectroscopy, indicating that addition of Ag induces the breaking of sulfur ring units and favors the creation of Ag-S-Ag bridging bonds. During this process, AgS3 pyramids and As4S4 molecules are formed, the latter being responsible for an increased photoinduced birefringence.