Effect of P-Type Last Barrier on Efficiency Droop of Blue InGaN Light-Emitting Diodes

P-type doping in the last barrier is proposed to improve the efficiency droop of the blue InGaN light-emitting diodes (LEDs). The light-current curves, energy band diagrams, carrier concentrations, radiative recombination efficiency, and internal quantum efficiency of the blue LEDs under study are investigated. The simulation results show that the efficiency droop is significantly improved when the last undoped GaN barrier in a typical blue LED is replaced by a p-type GaN barrier. The simulation results suggest that the improvement in efficiency droop is mainly due to the decrease of electron current leakage and increase of hole injection efficiency.