DFT-Calculations of Thermodynamic Parameters of ZnTe, ZnSe, ZnS Crystals

Abstract

Based on the analysis of the crystal and electronic structure of semiconductors ZnX (X=Te,Se,S) in cubic phase there have been built the cluster model for calculation of the geometric and thermodynamic parameters. The method of consideration of the boundary conditions for the proposed cluster models has been presented. Based on the results of ab initio quantum-chemical calculations of the crystal structure of molecular clusters the temperature dependence of formation energy ∆E, formation enthalpy ∆H, Gibbs free energy ∆G, entropy ∆S, specific heat capacity at constant volume CV have been defined. Computer calculations of the thermodynamic parameters were carried out with the help of density functional theory (DFT), using hybrid valence base set B3LYP. Also, in the work have been derived analytical expressions of temperature dependences of the presented thermodynamic parameters, which have been approximated by a quantum-chemical calculation data using mathematical package Maple 14.