Study of non-isothermal kinetics, electrical and optical properties of (GaSeTe) films

Abstract

Ternary Ga x Se 86− x Te 14 amorphous films ( x=15 and 36) were prepared by thermal evaporation. The results of differential scanning calorimetry (DSC) at different heating rates are reported and discussed. The glass transition activation energy, E t, and the crystallization activation energy, E c, were evaluated by measuring the heating rate dependence of the glass transition, crystallization onset and peak crystallization temperatures. The average calculated values of E t and E c are 140.29 and 97.89 kJ/mol, respectively. The electrical conductivity of amorphous Ga x Se 86− x Te 14 thin films with different thickness has been measured in the temperature range (263.2–333.3 K) and this allows the effect of introducing a metallic impurity to be observed. It was observed that conductivity increases with increasing activation energy and with a lowering of the pre-exponential factor, which suggests the results can be explained in terms of hopping conduction. The optical constants of these films were determined by transmission and reflection measurements at normal incidence in the spectral range of 500–800 nm. The refractive index has anomalous behavior in the spectral range 400–500 nm. The refractive index dispersion can be fitted to a single oscillator model.