Luminescence Efficiency of InGaN/GaN Quantum Wells on Bulk GaN Substrate

Time-integrated and time-resolved photoluminescence measurements on InGaN quantum wells grown by MOCVD on two different substrates (sapphire and GaN) show that the luminescence efficiency in these structures strongly depends on the intensity of carrier excitation. While at low excitation densities the recombination of excited carriers is governed by localization effects the behavior drastically changes at higher densities. At room temperature a suppression of nonradiative recombination could be observed that leads to an super linear increase of the luminescence.