Circular polarization of photoluminescence of GaAs/AlGaAs quantum wells as a function of their growth conditions

The degree of circular polarization of the photoluminescence of samples with GaAs/AlGaAs quantum wells grown with growth interruption at both interfaces and under conventional growth conditions has been investigated. It has been revealed that, at a low measurement temperature (4.2 K), the values of the circular polarization measured at different detection energies within the spectral profile of the luminescence band differ substantially for the sample grown with the growth interruption, whereas this effect is not observed for the sample grown without growth interruption. An increase in the sample temperature to 77 K leads to the disappearance of the effect under consideration. The observed behavior has been explained in terms of the model that accounts for a significantly different degree of localization of charge carriers in the growth islands (formed at the interfaces of the structure) with the spatial sizes determined by the specific growth conditions of the sample.