Thermodynamics of point defects in the AlSb phase and its influence on phase equilibrium

Abstract

This study presents a comprehensive theoretical analysis of the formation energies of native defects in the AlSb intermetallic phase. Ab initio calculations based on density functional theory (DFT) are used to determine the equilibrium concentration of intrinsic defects as a function of temperature, from which the theoretical homogeneity range of the AlSb phase is derived. The effect of extrinsic doping on carrier concentrations, including electrons and holes, is also investigated for several dopants, such as Cd, Ge, Se, Si, Te, and Zn. The results indicate a significant influence of doping, particularly in the absence of annealing, on the material’s carrier concentration, with important implications for its semiconducting properties. A new thermodynamic description of the Al-Sb system is also proposed based on the calculated defect formation energies. The model successfully reproduces thermochemical data and phase equilibria information available in the literature, including the phase diagram and mixing enthalpy. This work provides information on the thermodynamics of the Al-Sb phases and the possibilities of optimizing properties important for industrial applications.