First-principles calculations to investigate structural, electronic, piezoelectric and optical properties of Sc-Doped GaN

Abstract

Ab-initio calculations are performed to understand the effect of Sc incorporated into Wurtzite gallium nitride (GaN) on the optical properties to give a systematic idea of the spontaneous polarization Ps in Sc0.5Ga0.5N. Furthermore, the piezoelectric properties as piezoelectric constants e33, e31 and piezoelectric moduli d33 are calculated. The d33 values express that mixing 50% of GaN with 50% of ScN enhances the piezoelectricity. The spontaneous polarization of wurtzite Sc-doped GaN reached a theoretical predicted value, 0.023 C/m2 for concentration x = 0.5. In addition, the transverse value of piezoelectric coefficient e33 and moduli d33 equal to 1.8 C/m2 and 54.9 pC/N, respectively. Sc-doped GaN is a semiconductor material with a direct band gap that presents a prototype material for optoelectronic devices. So, it is necessary to give an idea about the different optical constants such as the dielectric function, refractive index, optical reflectivity and absorption coefficient. with using a degenerate perturbation k.p approach, which is implemented in all-electron package WIEN2k, the effective electron and hole masses are calculated.