Luminescence anisotropy of InGaP layers grown by liquid phase epitaxy

Abstract

We have studied the anisotropy of the photoluminescence (PL) of InGaP films grown by liquid phase epitaxy on GaAs substrates. The PL measurements were performed in a wide temperature range (4–250 K) and exciting power density range for polarizations of the emitted radiation along the [011] and [] directions. It was found that the donor–acceptor transition dominates at low temperature (4 K) while the band-to-band transition dominates at a higher temperature (250 K). The dependence of PL intensity on excitation intensity shows a characteristic behaviour for donor–acceptor recombination. The difference in the position of the spectral peak for [011] and [] polarizations is a result of the splitting of the valence-band into heavy- and light-hole bands due to strain. Moreover, the difference in the line shape of the spectra for different polarizations indicates the presence of anisotropy for different crystallographic directions.