The Effects of Mg Back Diffusion Capping Layers on the Performance Enhancement of Blue Light Emitting Diodes With a p-InGaN Last Barrier

The effects of thin Mg back diffusion capping layers on the performance enhancement of InGaN/GaN light emitting diodes (LEDs) with p-InGaN last barrier are investigated experimentally and numerically. By inserting a thin capping layer before the p-InGaN last barrier, the Mg back diffusion effect could be effectively suppressed and the optical performance of LEDs could be enhanced due to the improved hole injection and reduced electron leakage. What is more, the p-InGaN LED with GaN capping layer showed further reduced efficiency droop compared with that with InGaN capping layer as a result of the more uniform hole distribution in active layers.