Polarization anisotropy in the photoluminescence from InGaP layers grown by liquid phase epitaxy

The polarization anisotropy of the photoluminescence (PL) of InGaP films grown by liquid phase epitaxy (LPE) on GaAs substrates was studied. Photoluminescence measurements were performed in a wide temperature (4-250 K) range for emitted radiation polarized along the [0 1 1] and [0 1-bar 1] directions. Donor-acceptor transitions dominate at low temperature (4 K), while band-to-band transition does at higher temperature (250 K). A difference between the energy position of the spectral peaks for [0 1 1] and [0 1-bar 1] polarizations was found. This can be explained by the presence of compressive and tensile strained regions along the [0 1 1] direction. Moreover, the difference in the line shape of the spectra for different polarizations indicates the presence of anisotropy for these crystallographic directions