Photoluminescence line shape of excitons in GaAs single-quantum wells with and without heterointerface ordering

Abstract

The photoluminescence line shape of excitons at low temperatures is investigated in GaAs single-quantum wells grown by molecular-beam epitaxy with and without intentional heterointerface ordering. From the study of the excitation density dependence in the range between 1015 and 1017 cm−3, it is found that the inhomogeneous linewidth is significantly affected by band-filling effects of intrinsic defect states spatially localized in the wider wells. In the sample with heterointerface ordering the band-filling effects are directly identified by observation of saturation of the localized excitonic emissions, which are split as a result of increased spatial coherence of the excitonic states.