Effects of the insertion of InAs strain-compensating layers on photoluminescence properties of GaAsN/GaAs quantum-well structures

Microstructural and optical properties of strain-compensated and reference GaAsN/GaAs single quantum-well (QW) structures grown by metalorganic chemical vapour deposition were investigated using cross-sectional transmission electron microscopy (XTEM) and photoluminescence (PL), Significant enhancement of PL intensity and a blueshift of PL peak energy were observed in the GaAsN/GaAs QW structure inserted with three layers of 1 monolayer (ML) thick InAs compared with the reference sample. Dislocation-free InAs layers with 1 ML thickness were clearly observed by XTEM. However, InAs layers started to form clusters/dots when their thickness increases to 2 ML. Strain compensation and In-induced reduction of N incorporation are suggested to be two major factors affecting the optical properties.