Study of structural and thermodynamic properties of GaAs and InAs using Monte Carlo simulations

Abstract

Binary compound semiconductor alloys such as GaAs and InAs find extensive use in our daily lives. This study predicts the structural and thermodynamic properties such as the lattice constant, linear thermal expansion coefficient, nearest neighbour distances and molar heat capacities at constant volume, and their variations with temperature using Monte Carlo simulations. The Tersoff potential model is used to describe the interatomic interactions and the model is validated by comparing the predicted properties against experimental data for GaAs. The simulation results for the GaAs alloy show good agreement with literature data for lattice constant and bond length measurements. Linear thermal expansion coefficients are overestimated consistently as compared to experimental data for all temperatures. Low temperature range thermal expansion coefficient data capture qualitative behaviour but is unable to accurately predict quantitative data. The specific heat at constant volume measured at high temperatures follows the Dulong–Petit law. Having established the validity of the Tersoff potential in modelling III–V binary alloys, the same properties and their variance with temperature are determined for the InAs alloy.