Optical and other physical characteristics of amorphous Ge-Se-Ag alloys

Measurements of optical properties and differential thermal analysis have been made on alloyed samples of Go and Se with Ag, prepared under vacuum to evaluate their glass-forming tendencies. Optical absorption measurements showed that the fundamental absorption edge is a function of composition. The optical absorption is due to direct transition and the energy gap increases with the increase of Ag content. The average heat of atomization and related parameters such as the average coordination number N-eo the number of constraints per atom, N-eon, were also calculated. It was found that there is a correlation between the glass-forming ability and the number of lone-pair electrons L. An attempt has been made to evaluate the correlation according to the Liang criterion. Our experimental results support this criterion. (C) 2001 Elsevier Science B.V. All rights reserved.