Localization lengths of the electrons and holes in InGaN/GaN quantum wells have been calculated using numerical solutions of the effective mass Schr\"odinger equation. We have treated the distribution of indium atoms as random and found that the resultant fluctuations in alloy concentration can localize the carriers. By using a locally varying indium concentration function we have calculated the contribution to the potential energy of the carriers from band gap fluctuations, the deformation potential, and the spontaneous and piezoelectric fields. We have considered the effect of well width fluctuations and found that these contribute to electron localization, but not to hole localization. We also simulate low temperature photoluminescence spectra and find good agreement with experiment.

An ${\mathrm{In}}_x{\mathrm{Ga}}_{1-x}\mathrm{N}∕\mathrm{Ga}\mathrm{N}$ multiple quantum well (MQW) structure that exhibited bright photoluminescence was examined with the three-dimensional atom probe. The quantum wells were clearly imaged and the indium fraction $x$ measured to be $0.19\pm 0.01$ , in good agreement with x-ray diffraction measurements. The distribution of indium in the MQWs was analyzed: no evidence for either high indium concentration regions or indium clustering was found, in contrast with many of the transmission electron microscopy studies in the literature. The authors conclude that indium clustering is not necessary for bright luminescence in InGaN.

We describe the growth of InGaN quantum dots (QDs) by metalorganic vapor phase epitaxy. A thin InGaN epilayer is grown on a GaN buffer layer and then annealed at the growth temperature in molecular nitrogen inducing quantum dot formation. Microphotoluminescence studies of these QDs reveal sharp peaks with typical linewidths of $\text{∼700\hspace{0.17em}μ}\mathrm{eV}$ at 4.2 K, the linewidth being limited by the spectral resolution. Time-resolved photoluminescence suggests that the excitons in these structures have lifetimes in excess of 2 ns at 4.2 K.