Crystallization kinetics of a-Se, part 4: thin films

Abstract

Differential scanning calorimetry was used to study the crystallization behaviour of selenium thin films in dependence on film thickness and deposition rate. In the current work, which is the fourth in a sequence of articles dealing with crystallization kinetics of a-Se, the non-isothermal crystallization kinetics was described in terms of the Johnson-Mehl-Avrami nucleation-growth model. Two-dimensional crystallite growth, consistent with the idea of sterically restricted crystallization in a thin layer, was confirmed for all data. It was found that neither the film thickness (tested within the 100–2350 nm range) nor the deposition rate appears to have any significant influence on the crystallization kinetics. However, the higher amount of intrinsic defects possibly produced by a higher deposition rate seems to accelerate the crystallization, shifting it towards lower temperatures. Very good correlation between the results obtained for thin films and those for fine powders was found. Based on the obtained results, interpretations of relevant literature data were made.