Luminescence properties of isolated InGaN/GaN quantum dots

InxGa1–xN quantum dots have been fabricated by the selective growth of GaN micro-pyramid arrays topped with InGaN/GaN quantum wells. The spatially- and spectrally-resolved luminescence properties of these structures were measured using low-temperature micro-photoluminescence spectroscopy. The presence of
InGaN quantum dots was confirmed directly by the observation of sharp peaks in the emission spectrum at the pyramid apices. These luminescence peaks exhibit linewidths down to 650 μeV (limited by the spectrometer resolution). We describe the broadening of the luminescence peak from a single dot as a function of temperature and excitation power.