The effect of the structure on the physical properties in GexAs10Se90-x glasses.

We have prepared a group of GexAs10Se90-x glass(x=5, 10, 15, 20, 25, 30, and 35 at. %) and investigated their structure and physical properties. It was found that, the minimum refractive index and maximum optical bandgap occur in Ge25As10Se65 glass that is chemically stoichiometric. Analysis of Raman spectra of the glasses indicated that the number of the Ge-Ge, As-As, and Se-Se homopolar bonds is closely related to the bandgap, because the band-tails formed by homopolar bonds could reduce the optical bandgap. The transition behavior of the structural units and physical properties of the glasses occurs at the glass with the chemically stoichiometric composition, and thus the chemical composition dominates physical properties of GexAs10Se90-x chalcogenide glasses. [ABSTRACT FROM AUTHOR]