Effects of the growth pressure of a-plane InGaN/GaN multi-quantum wells on the optical performance of light-emitting diodes

Here, we report the effects of the growth pressure of InGaN/GaN multiple quantum wells (MQWs) on the structural and optical characteristics in a-plane InGaN-based light-emitting diodes (LEDs). A blue-shifted electroluminescence (EL) peak wavelength was observed as the growth pressure increased from 100 to 400 mbar. Moreover, the LED with MQWs grown at 200 mbar had a threefold higher EL peak intensity than that of an LED using MQWs grown at 300 mbar. The experimental results can be explained by the structural qualities of MQWs with different dislocation density and interface abruptness due to changes in growth pressure. The relatively higher growth pressure improves the crystal quality in a-plane InGaN well layers, but the properties of surface morphology in GaN barrier layers are degraded. (paper)