OPTICAL AND ELECTRICAL-PROPERTIES OF AG-AS-S GLASSES

Physical properties of Ag2S-As2S3 glassy alloys have been studied as a function of the Ag atomic concentration x. With an increase in x, the optical-absorption edge exhibits a red shift, while the steepness of the Urbach tail changes little. In the glasses with x≥15, the electrical conductivity is governed by Ag+ ionic conduction. The ionic conductivity exponentially increases with x, and in contrast the hole conductivity hardly changes with x; however, the activation energies for the ionic and the hole conductivity are nearly the same at about 0.4 eV for compositions with 15 ≤x≤35. These observations are discussed on the basis of atomic and electronic structures in Ag2S-As2S 3 glasses. © 1995 American Institute of Physics.