Time-resolved photoluminescence study of InGaAs–GaAs single heterostructures

Abstract

We report the results of time-resolved photoluminescence studies of the near band-gap emission from relaxed, nonpseudomorphic In0.06Ga0.94As layers grown by metal-organic vapour-phase epitaxy on GaAs substrates oriented exactly on the (001) plane and misoriented by 2° off (001) towards <110>. The layer grown on the misoriented substrate shows a narrow excitonic emission whose lifetime of 1.2 ns is indicative of the high quality of the material. The emission from the layer grown on the oriented substrate consists of four bands. Their time-resolved spectra indicate that they can be attributed to excitons bound to different distributions of levels located either in homogeneous, strain-free regions or in regions near the epilayer misfit dislocations. We also present evidence indicating that hydrogen is more readily incorporated in layers grown on oriented substrates.