Effects of built-in electric field on photoluminescence decaytime of GaN self-assembled quantum dots

摘要

Size dependence of photoluminescence (PL) decay time in GaN self-assembled quantumdots (SAQDs) is investigated. Two samples having different average size of QDs wereprepared. The measurement has revealed that larger QD sample shows longer PL decaytime and smaller emssion energy than smaller one. The dependence of PL decay time onemission energy in both samples smoothly connects with each other. The PL decay timestrongly increase by almost three orders magnitude with decreasing the emmision energy, thatis, with increasing the size of QD. The increase of PL decay time with increasing the size ofGaN SAQDs is attributed to the reduced oscillator-strength due to the strong built-in electricfield in the GaN/AlN heterostructures.