The influence of impurity concentration on exciton photoluminescence in GaAs and InP

Abstract

The authors report an investigation of the exciton photoluminescence (PL) spectra of high-purity nominally n-type GaAs and InP layers, grown by metalorganic vapour phase epitaxy. The results are discussed in terms of exciton-polariton kinetics. The ratio of the integrated emission intensities of neutral donor-bound exciton (D0, X) transitions and free exciton-polariton (FX) transitions rDF=I(D0, X)/I(FX) shows a sublinear dependence upon neutral donor concentration nD0 deduced from 77 K Hall measurements. This relationship is particularly useful for estimating carrier concentrations in high-purity materials, which cannot be characterized by Hall measurements due to depletion.