The electronic and optical properties of InGaAs/InP and InAlAs/InP superlattices

We study using first-principle calculations the electronic and optical properties of In _0.5Ga _0.5As/InP and In _0.5Al _0.5As/InP superlattices, where the InGaAs and InAlAs alloys are described through an appropriate ordered ternary structure. The calculated electronic properties show that the substitution of Ga with Al originate an opening of the band gap from the infrared to the near visible and a transformation of the band alignment from type I to type II. Through the analysis of the optical properties we discuss successfully the giant polarization anisotropy observed in these systems.