Growth of GaAsBi/GaAs multiple quantum wells with up to 120 periods

Abstract

In this work, we demonstrate the MBE growth of a systematic series of GaAsBi/GaAs multiple quantum well devices with up to 120 periods and report on their structural and optical characterisation. TEM images confirm the incorporation of a record number of wells for this material, while showing reasonable thickness uniformity. Fitting of the XRD data becomes worse as the number of quantum wells increases due to strain relaxation and out-of-plane growth inhomogeneity. The devices are compared to a previous series of devices grown in our group using PL and are found to have less severe strain relaxation due to the thicker barriers and lower average strain in the MQW stack, despite containing a greater number of wells.