Synthesis and characterization of Cu2O center dot TeO2 and CuI center dot Cu2O center dot TeO2 glasses

Cu2O . TeO2 and CuI . Cu2O . TeO2 glasses were synthesized and characterize d by complex impedance measurement, Raman spectroscopy, X-ray photoelectron spectroscopy, and atomic force microscopy techniques. Samples of the binar y and the ternary systems are found to have both Cu+ and Cu-2+ with their r elative concentration being composition dependent. Bonds like -O-Cu2+-O-, l eading to the formation of bridging oxygen are found to form in the binary system. Structural units like (Te3O84-)(n) are also found to form when Cu2O content is high in the binary system. Phase separation is observed in the ternary system. The glass structure and hence the ionic conduction behavior are found to depend upon chemical composition. When CuI content exceeds 60 mol%, the crystalline phase of alpha-CuI gets stabilized at room temperatu re, thus causing the enhancement in conductivity. (C) 2000 Kluwer Academic Publishers.