Glass formation in germanium telluride glasses containing metallic additives

Abstract

Differential scanning calorimetric (DSC) studies have been carried out on germanium telluride glasses containing Cu and Ag. Both Cu_xGe₁₅Te_85-x (2≤x≤10) and Ag_xGe₁₅Te_85-x (2.5≤x≤21.5) glasses are found to exhibit single glass transition and single crystallization. On the basis of the devitrification behaviour of these glasses one can conclude that the network connectivity of the parent Ge-Te matrix is not improved by the addition of Cu whereas Ag improves the connectivity. Over-constraining of the structural network for x>5 is rapid in Cu added glasses and more gradual in Ag added glasses. The difference in the glass formation in the Cu-Ge-Te and Ag-Ge-Te systems is understood in light of the above differences in the structural network.