Highly efficient yellow photoluminescence from {11–22} InGaN multiquantum-well grown on nanoscale pyramid structure

InGaN/GaN multiquantum wells (MQWs) with a peak wavelength of 570 nm are grown on nanosize GaN hexagonal pyramid structures. Temperature dependent photoluminescence (PL) measurements from 10 to 300 K show a high integrated intensity ratio of 0.45. The emission energy of the MQW monotonically decreases with temperature increase, showing the absence of localized potential. Power dependent PL shows no noticeable blueshift caused by piezoelectric field screening effect. Comparative study of the PL results with those of the InGaN MQW on microsize pyramid show that nanosize pyramids play an important role in suppressing piezoelectric field in addition to the semipolar growth direction. We attribute the high luminescence efficiency of the MQW on nanosize pyramid structures to effectively suppressed piezoelectric field and potential localization.