Influence of stress on the optical properties of double InGaN/GaN multiple quantum wells

The optical properties of double (a blue and a green) InGaN/GaN multiple quantum wells (MQWs) on unstressed bulk GaN and a compressive stressed GaN template on patterned sapphire substrate (PSS) were investigated. Photoluminescence intensity of green MQWs on bulk GaN was about 6 times higher than that on GaN/PSS, while the intensity difference of blue MQWs was less than two times. It was found that the existing stress played an important role in the difference in luminescence. Furthermore, the V-shape pits in blue MQWs stemmed from the pre-existing dislocations while those in green MQWs were derived from the new dislocations. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement