Semi-polar (20–21) InGaN/GaN multiple quantum wells grown on patterned sapphire substrate with internal quantum efficiency up to 52 per cent

Abstract

This letter reports three semi-polar (20–21) InGaN/GaN multiple quantum wells (MQWs) on patterned sapphire substrates. The well and barrier thicknesses are 3.5 nm and 9.5 nm, respectively, and the indium contents are estimated to be from 9% to 26%. As a consequence of its high crystal quality, the semi-polar sample, with an emission wavelength of 460 nm, exhibits an internal quantum efficiency (IQE) of up to 52%, based on photoluminescence (PL) measurements. Furthermore, we find that carriers are confined in deep localization centers, which enable the major carriers to recombine radiatively, even at room temperature.