Non-isothermal crystallization kinetics of GeTe4 infrared glass

Non-isothermal crystallization kinetics of the GeTe4 chalcogenide glass was studied in dependence on particle size. Complexity of the obtained DSC data was treated by means of the Fraser-Suzuki deconvolution, and the particular crystallization sub-processes were identified and described in terms of the JMA(2) and AC kinetic models. Bulk as-prepared GeTe4 samples, on the other hand, exhibited simple zero-order (F0) crystallization kinetics. The marked difference between the powder and bulk crystallization mechanisms was explained based on the mechanically induced defects and heterogeneities, which surrogate/accelerate the primary nucleation process. This concept also accounts for the remarkable stability of the studied telluride glass. Precipitation of Te followed by second-stage GeTe crystal growth was confirmed by XRD for all of the applied experimental conditions. The dominant influence of the nucleation process on the consequent crystallization kinetics is thereby implicated. Infrared microscopy was used to confirm the existence of the particular crystallization mechanism.