High linear polarization of photoluminescence of GaInP epilayers at low temperature

Polarization of the photoluminescence (PL) emission depends on the crystal symmetry. The change of temperature results in elastic strain modification. Here we study temperature dependence of the linear polarization of the PL emission from the (001) surface of ordered GaInP epitaxial semiconductor alloys with high ordering parameters, and compare experimentally obtained PL polarization degree with that obtained on base of calculations. We explain high PL polarization observed at low temperature in terms of selection rules for band-to-band transitions derived from k·p theory. In the calculations we take into account changes of the alloy crystal symmetry due to atomic ordering, elastic biaxial and in-plane uniaxial strain in GaInP epilayer, and show how the crystal symmetry influences the PL polarization. Consideration of uniaxial, as well as biaxial strain provides an accurate description of the PL polarization as a function of temperature.