Study of Structural, Optical and Thermodynamic Properties of Indium Phosphide (InP) Using First Principle Density Functional Theories

Abstract

The structural, electronic and optical properties of Indium phosphide (InP) were investigated using DFT. In order to improve calculation accuracy, the convergence test of total energy with regard to the kinetic energy cutoff, k-point, and lattice constant of InP was carried out using the GGA-PBE approximation. The calculated band gap value of InP is 1.94ev and overestimated compared to experimental value1.35eV. The optical properties of InP have been investigated in the photon energy range 0 to 25eV. The optical characteristics such as real dielectric function and imaginary dielectric function, extinction coefficient, refractive index, reflectivity and absorption coefficient were determined by the GGA-PBE method and are also in accordance with the known theoretical and experimental data. Additionally, the GGA-PBE peak for the absorption coefficient was discovered at around 5.85eV and shows good absorption characteristics for the incident photons in the visible part of the solar irradiation. The temperature dependencies of vibrational energy, free energy, entropy and heat capacity of InP were calculated within room temperature and all are fairly in good agreement with experimental values.