Analysis of thermal processes in Cu<inf>x</inf>(AsTe)<inf>100-x</inf>glasses

Abstract

Chalcogenide glasses are promising materials for application in fiber optics and all-optical switching devices at telecommunication wavelengths, due to both their high transparency in the infrared region and their nonlinear refractive index. In this paper we present and discuss the results of the analysis of the processes that occur during the thermal treatment of the Cux(AsTe)100-xglass system, x = 5 and 20 at.%. Our analysis is based on differential scanning calorimetry (DSC) curves, recorded in non-isothermal measurement conditions in temperature intervals of 300-770 K, at a heating rate of β = 10 K min-1. Samples with x = 20 at.% are thermally treated at four different heating rates in order to implement kinetic analysis of the processes. The activation energy of the crystallization Ecis determined by the Kissinger and Mahadevan methods. The characteristic parameters of the crystallization process are determined using the Matusita method. We conclude that nucleation occurs in three dimensions and within the volume. The amorphous character of the as-prepared samples is verified by x-ray. A diffractogram of the glass sample with x = 20 at.%, which was annealed at a temperature close to the crystallization temperature established by the DSC analysis, shows that structural units of copper with arsenic and copper with arsenic and telluride are formed within the amorphous matrix. © 2013 The Royal Swedish Academy of Sciences.