Strong carrier confinement and negligible piezoelectric effect in InGaN/GaN quantum dots

We report photoluminescence and time-resolved photoluminescence experiments on InxGa1-xN/GaN quantum dots grown by plasma-assisted molecular beam epitaxy. Single dot spectroscopy was used to prove the quantum dot origin of the luminescence. in addition, we show that both the photoluminescence intensity and the carrier recombination time remain constant upto 200 K, reflecting the strong confinement of the carriers. We also found that this strong confinement prevents the carriers from being affected by the huge internal electric field, which are generally reported in wurtzite-structured III-nitride quantum dots. (C) 2007 Elsevier B.V. All rights reserved.