Enhancement of carrier localization effect and internal quantum efficiency through In-rich InGaN quantum dots

InGaN-based light emitting diodes have a problem known as green gap. InGaN quantum dots have been proven to be a kind of promising structure to solve this problem due to its strong carrier localization effect. In this study we fabricated InGaN/GaN quantum dots and conventional InGaN/GaN multiple quantum wells by tuning growth mode and compared their quantum confined stark effect and internal quantum efficiency by means of intensity-dependent as well as temperature-dependent photoluminescence measurements. It was found that the surface morphology transited from two dimensional step flow to three dimensional quantum dots with increasing the well thickness. In addition the quantum confined stark effect was weakened as a result of releasing the compressive strain. Furthermore, the internal quantum efficiency of the quantum-dot structures was four times higher than that of the conventional multiple quantum wells due to the enhancement of carrier localization effect.