Optical studies on InAs/InGaAs/GaNAs strain-compensated quantum dots grown on GaAs (0 0 1) by molecular beam epitaxy

Abstract

We have investigated the growth of 10 stacked layers of self-assembled InAs quantum dots (QDs) on GaAs (0 0 1) substrates, which were embedded in a combined set of a GaNAs strain-compensating layer (SCL) and an InGaAs strain-reducing layer (SRL). The internal compressive strain induced by each InAs QD layer was compensated by a tensile strain due to a GaNAs SCL. Consequently, the photoluminescence (PL) measured at 30 K showed a narrower linewidth of 60.3 meV for the sample with GaN 0.008As 0.992 SCL compared to 94.2 meV for InAs/GaAs uncontrolled sample due to an improved QD size uniformity. In order to reduce the nominal lattice mismatch at the heterointerface, we propose to insert an InGaAs SRL between the InAs QD layer and GaNAs SCL. We observed a PL peak redshift up to 1230 nm at room temperature, and increased PL intensity for InAs QD/InGaAs SRL/GaNAs SCL samples.