Elastic moduli and theoretical estimations of physical properties of Ge3Se7–As2Te3

The Bulk (100-x)Ge3Se7 - (x)As2Te3 (0 ≤ x ≤ 30) glassy alloys were prepared using the melt quenching technique. The elastic moduli (Bulk (K), Micro-hardness (H), Young (Y)), and Poisson's ratio (Pr) of the prepared glasses have been determined using the measured values of the ultrasonic velocities and density (ρ). Values of ρ were measured, then the molar volume (Vm) was estimated theoretically. The DSC thermograms are used to determine the glass transition temperature (Tg). The thermal evaporation method was used to prepare the (100-x)Ge3Se7- (x)As2Te3 (0 ≤ x ≤ 30) thin films under a vacuum of about 10−4Pa. The absorbance (A) of the films in the spectral range from 0.45 to 0.85 μm has been measured, then the absorption coefficient (α) and energy gap (Eg) were determined. The Chemical Bond Approach (CBA) has been used successfully to estimate theoretically various physical and structural characteristics of the studied system. Theoretical values of Eg and Tg have been obtained using different methods. The results proved a remarkable agreement between the theoretical and experimental values for both the Eg and Tg. The Eg values decreased from 2.1 to 1.73 eV by increasing the As2Te3 content from 0 to 30 at. %. Therefore, these compounds can be used as an absorbing layer for electromagnetic radiation in photovoltaic devices and sensors.