Crystallization kinetics of Se–Te thin films

• Non-isothermal crystallization of Se(1 − x)Tex thin films was studied by DSC for x ≤ 0.3.
• The crystallization kinetics were described in terms of Johnson–Mehl–Avrami model.
• Apparent activation energy of crystallization exhibits step-like compositional behavior.
• Two-dimensional growth of crystallites was confirmed.
• Signs of the transition between the spherulitic A and B modes were found.

Differential scanning calorimetry was used to study the non-isothermal crystallization behavior of selenium–tellurium thin films within the 0–30 at.% Te compositional range. The non-isothermal crystallization kinetics were described in terms of the Johnson–Mehl–Avrami nucleation-growth model. The apparent activation energy of crystallization was found to exhibit a step-like compositional behavior, with E changing from ~ 115 to ~ 145 kJ·mol− 1 in the 10–15 at.% Te range. Two-dimensional growth of crystallites, consistent with the idea of sterically restricted crystallization in a thin layer, was confirmed for all data. However, in the case of the Se70Te30 thin film, indications of three-dimensional crystal growth were found at high heating rates. This corresponds to the previously reported behavior of Se–Te chalcogenide matrices, where the addition of tellurium leads to the formation of smaller, volume-located crystallites.