MOCVD Growth and Characterization of Near-Surface InGaN/GaN Single Quantum Wells for Non-Radiative Coupling of Optical Exitations

We report a study of the structural and optical properties of near-surface InGaN/GaN single quantum wells, grown by metalorganic chemical vapour deposition, as a function of underneath layer structure and GaN capping thickness. Special attention is paid to characterize properties which are important for non-radiative coupling applications, such as emission intensity at peak wavelength and surface morphology. We observe that utilization of indium containing underneath structures results in high optical quality while increasing surface roughness. Optical performance can be further improved with InGaN/GaN superlattice structures instead of a single InGaN underneath layer. Time-resolved photoluminescence measurements of samples with different GaN capping thicknesses show that room temperature photoluminescence decay time increases with decreasing GaN capping thickness until surface states related non-radiative recombination processes start to play a significant role at very small capping thicknesses