Impact of Ga Doping on the Physical Properties of Ge-S-Ga Glassy Alloy

The effect of Ga doping on the physical properties i.e., density, packing density, molar volume, cohesive energy and band gap of Ge20S80-xGax glassy alloy is investigated theoretically. An increase in the density, packing density and the molar volume has been observed with an increase in gallium content. Optical band gap of thin films is calculated by Shimakawa's relation. It is found that the optical band gap decreases with an increase in Ga content. The decrease in optical band gap is attributed to the decrease in cohesive energy and formation of defect states above the valence band. The physical properties obtained are in good agreement with earlier reported results.