Thermal Stability and Tg Characteristics of GeTeSb Glasses

Important physical properties, such as coordination number and mean bond energy of Te based chalcogenide system (GeTeSb) are studied for different Te contents, each one with different compositions when replacing Ge atoms with Sb ones. We found that these properties decrease with increasing Sb contents, and hence with decrease of average coordination number. The thermal stability of the system is evaluated according to Dietzel criterion ∆T. The glass transition temperature Tg is then deduced with a suitable proportionality with the mean bond energy and compared to experiment values. This glass temperature is also found to be related with linear function to the average coordination number according to Gibbs-DiMarzio modified equation and the parameters T0 and β are determined.