Amorphous-to-crystalline transition in Te-doped Ge2Sb2Se5 glass

Differential scanning calorimetry (DSC) was used to study crystallization in Ge₂Sb₂Se_4.5Te_0.5 glass under non-isothermal conditions. The crystallization kinetics was described in terms of the autocatalytic ?esták–Berggren model. An extensive discussion of all aspects of a full-scale kinetic study for a crystallization process was undertaken. In particular, the effect of Te ? Se substitution on the complexity of the crystallization process was analyzed. The addition of tellurium enhances bulk crystallization originating from volume nuclei at the expense of the surface/defects-based crystallization mechanism. Significantly higher activation energy in the case of the Te-doped material was attributed to the larger mass of the combined Se–Te chains and the larger spatial restrictions for their movement. On the other hand, the slightly lower crystallization temperature of the Te-doped glass corresponds to its higher tendency for crystallization. A supplemental X-ray diffraction study confirmed the findings obtained by DSC.