Pseudo-potential calculations of the electronic and optical properties of GaxAlyIn1–x–yAs

A method for calculating the electronic structure of the quaternary alloy GaAlInAs is presented with zinc blende structure. We have used the empirical pseudo-potential method coupled with the virtual crystal approximation (VCA). The electronic structures are studied for GaAlInAs (x = 0.24, y = 0.24) and GaAlInAs lattice matched to InP as well GaAs. In addition a method for calculating the refractive index is presented, which we used the Sellmeir model. The composition dependence of the refractive index is discussed, the results indicate that refractive index decrease with alloying composition of the quaternary alloy GaAlInAs lattice matched to InP and GaAs.