Thermal processes contributions to the temperature dependence of the energy gap in dilute bismuth III-V alloys

Abstract

This paper presents a methodological analysis of the gap energy temperature dependence of GaAsBi, GaSbBi, InSbBi, and InAsBi. The temperature dependence of the gap energy in these alloys has been analyzed by considering separately the contributions due to thermal expansion and electron-phonon interaction based on Varshni, Viňa, and Pässler models. For the thermal expansion contribution, we use a term that explicitly takes into account the temperature variation of the thermal expansion coefficient and the pressure variation of the bandgap. The thermal expansion coefficient of semi-metallic compounds X–Bi (X = Ga or In) and III-V-Bi alloys is estimated on the basis of the physical properties of material atomic constitution. The overview of different results indicates the competition between the two processes in the temperature sensitivity of bandgap energy referring to a critical temperature of about100K. The coexistence of Bi and Sb has a particular influence on the fitting physical parameters issuing from different fits.