Effect of Bi Additions upon the Physical Properties of Germanium Telluride Glassy Semiconductors

The effect of bismuth (Bi) additions upon the physical properties, coordination number (m), constraints (Nc), density (ρ), molar volume (Vm), cohesive energy (CE), lone pair electrons (L) and glass transition temperature (Tg) of Ge20Te80-xBix (x = 0, 1.5, 2.5, 5.0) bulk glassy alloy has been investigated. The density and molar volume of the glassy alloys has been found to increase with increasing Bi content. The CE of the investigated samples has been calculated by using the chemical bond approach (CBA) and is correlated with a decrease in the optical band-gap with increasing Bi content. The glass transition temperature has been estimated by using the Tichy–Ticha approach and was found to increase with an increase in the Bi content.