The crystallization characteristics for Ge18Bi4Se78 glass are studied in this work by means of differential thermal analysis (DTA) under non-isothermal conditions. One stage endothermic glass transition and one exothermic crystallization are observed in the DTA curves. The results of topological constraints for Ge18Bi4Se78 glass show that the calculated value of glass transition temperature (Tg) is very close to that of the experimental results. The as-prepared, as well as the annealed samples, are examined using x-ray diffraction (XRD), energy dispersive x-ray spectroscopy (EDX), scan electron microscope (SEM) techniques. Avrami’s exponent (n) found to have an average value of 1.61 ± 0.2 reveals a mixture of one dimensional and surface nucleation stages of growth. Many models are used to estimate the activation energies for glass transition (Eg) and crystallization (Ec). The crystallization process was found to be described by the Sestak- Berggren SB(M, N) model.

A series of Ge18BixSe82-x (x= 0.5, 2, 4, 6& 8) thin films were prepared using thermal evaporation on glass substrates. The structural, optical and electrical properties of the prepared samples were investigated. The samples were exposed to γ-ray of 60Co source with gradually increased doses up to (150 kGy). The changes of the properties of the irradiated samples have been studied. Single oscillator and Drude models were used to describe the dispersion region. The changes of the optical parameters such as optical energy gap (Eop), Urbach energy (Eu), and the plasma frequency (ωp ) due to gamma irradiation were studied. The results obtained were explained in terms of the interaction of radiation with matter. The electrical conductivity was studied for both the as-prepared and irradiated films revealing negative differential conductance behavior.