Influence of Ge Addition on physical, optical, and mechanical properties of S-Se-Pb chalcogenide glasses

A new series of Ge-incorporated chalcogenide S-Se-Pb glasses is synthesized by the melt-quenching technique. The amorphous nature of the synthesized compounds has been checked by X-ray diffraction. The measured density increases from (3.02-3.54)g.cm^-3 due to the incorporation of Ge atoms. The estimated optical energy band gap decreases from (2.04-1.71) eV, whereas the Urbach energy increases from (0.16- 0.35) eV, demonstrating the manifestation of structural disorder. The Wemple-Di Domenico model is deployed for the dispersion analysis. The complex dielectric constant, dissipation factor, and loss functions, i.e., VELF and SELF parameters, are computed and systematically interpreted. Elastic moduli of the studied glass samples are obtained from the measured longitudinal and transverse velocities. The study reveals an upsurge in longitudinal modulus from (22.87 – 37.85) GPa and Young’s modulus from (19.01-32.05) GPa with increasing Ge atoms. Theoretical values of elastic moduli acquired from Bond compression model are in agreement with the experimentally obtained results. The obtained findings suggest that among all the studied samples, the S_(50−x)Se₄₀Pb₁₀Geₓ (x = 20) sample has the best optical features and highest mechanical stability, which can be used for optoelectronic applications.