Ordering induced splitting in light-hole and heavy-hole bands in GaInP grown by organometallic vapor-phase epitaxy

The origin of the polarization of the photoluminescence in ordered InGaP is investigated. The ordering induced lowering of the cubic crystal symmetry is caused by a superlattice and/or strain effects in two of the four 〈111〉 crystal directions resulting in a splitting of the heavy-hole and light-hole valence bands. Using simple arguments from k⋅p theory, the difference in photon energy as well as the intensity ratio of the luminescence in the two polarization directions along the cleavage facets is explained as a function of temperature.