Mechanical properties and band gap estimations of stoichiometric GeSe2-As2Se3 glasses

Abstract

The elastic moduli (Bulk (Ke), Micro-hardness (He), Young (Ye)) and Poisson’s ratio (Pr) of the prepared xGeSe2-(100-x)As2Se3 (0 ≤ x ≤ 100) glasses are estimated using the ultrasonic velocities (Longitudinal (νl) and Transverse wave (νt)) and the density (ρ). The glass transition temperature (Tg) of the glasses has been obtained using the DSC thermograms recorded at a heating rate 10 K/min. As well, many physical and structural features have been obtained theoretically by applying the Chemical Bond Approach (CBA). Theoretical evaluations of optical band-gap (Eg) and the glass-transition temperature (Tg) for the glasses have been studied. It was found that the obtained theoretical values of the parameters Eg and Tg agree with the experimental values within uncertainty < 4%. Also, rigidity parameters such as the heat of atomization (Hs), the mean bond energy (Es), the cohesive energy (CE), and the overall average bond energy (< E > ) have been estimated. The dependence of Eg on the rigidity parameters (Hs, Es, CE, and < E > ) was verified and discussed. Furthermore, the coordination number (CN), lone pair electrons (LP), and crosslinking density (CD) were estimated. Eg values increased from 1.6 to 2.04 eV with increasing the GeSe2 concentration from 0 to 100 at%. So, these materials can be used as optical absorbers in solar cells and sensors.