Effects of strain, substrate misorientation, and excitonic transition on the optical polarization of ordered zinc-blende semiconductor alloys

Optical polarization in ordered ${\mathrm{GaInP}}_{\mathrm{2}}$ alloys has been studied by low-temperature photoluminescence. A perturbative theory that includes the effects of lattice mismatch, substrate misorientation, and excitonic transitions has been developed for making quantitative comparisons between experimental results and theoretical predictions. We show that to obtain quantitative information about ordering from the polarization of near-band-gap transitions, all of the above-mentioned effects should be taken into account. This study demonstrates that the electronic and optical properties of a monolayer superlattice formed by partial ordering in the ${\mathrm{GaInP}}_{\mathrm{2}}$ alloy can be well described by a simple perturbative Hamiltonian, i.e., a quasicubic model.