Indium aggregated quantum dot structures in InGaN compounds

We will summarize the optical characteristics and microstructures of the indium-aggregated quantum dots in InGaN compounds, including intended InGaN/GaN quantum well structures and InGaN epi-layers. In quantum well structures, the dependencies of optical properties and material structures on well width and nominal indium content are to be discussed. Also, the effects of silicon doping will be reported. Furthermore, the effects of post-growth thermal annealing on the formation of quantum dot-like structures and their variations of optical properties will be presented. In InGaN epi-layers, we have studied the optical and material properties of such films with high indium contents. From the images of cathodo-luminescence and high-resolution transmission electron microscopy, quantum dot structures could be observed. After thermal annealing, the original yellow emission became blue in color in one of the samples. In the other sample, the original red emission became the combination of red, yellow and blue photons, leading to white in color.