Temperature Dependent Polarized-Piezoreflectance Study of Near Direct Band Edge Interband Transitions of AlInP2

We report a detailed temperature dependent study of polarized piezoreflectance (PzR) for two AlInP2 epilayers that exhibit different degree of ordering in the range between 23 and 500 K. The polarized PzR measurements showed anisotropic character along the [110] and [110] directions for the partially ordered sample. The PzR spectra were fitted using the first-derivative of a Lorentzian line shape functional form. The direct band-, crystal field splitting- and spin-orbit splitting to conduction band transition energies which are denoted as Eg, Eg+ΔE12 and Eg+ΔE13 respectively, at various temperatures were accurately determined. The temperature dependence of these near direct band-edge critical points transition energies were analyzed by the Varshni expression and an expression containing the Bose-Einstein occupation factor for phonons. The parameters that describe the temperature variation of transition energies were evaluated and discussed.