Band structure, charge distribution and optical properties of AlpxSb1-X ternary semiconductor alloys

Abstract

The present contribution studies on the composition dependence of the electronic and optical properties of the zinc-blende alloy system AlPxSb1-x. The calculations are performed using a pseudopotential approach under the virtual crystal approximation. Features such as electronic band structure, energy band-gaps, refractive index, dielectric constants and valence and conduction charge densities are determined and their compositional dependence are examined and discussed. The aim of this paper is to provide new data for electronic and optical properties by varying the alloy composition x and to see to what extent the compositional disorder affects the properties of interest. The effect of alloy disorder on the energy band-gaps and electron charge densities is found to be important for getting a meaningful agreement with experiment. Our results show a direct-band gap bowing parameter of 2.7 eV which agrees very well with experiment. Moreover, a transition between indirect band gaps is found to occur twice. Besides, bonding and ionicity are discussed in terms of electron charge distribution. The information derived from the present study can be useful for optoelectronics applications.