Numerical analysis of using superlattice-AlGaN/InGaN as electron blocking layer in green InGaN light-emitting diodes

In this study, a specific design on the electron blocking layer (EBL) by band engineering is investigated numerically with an aim to improve the output performance and to reduce the efficiency droop in green LEDs. Systematic analyses including the energy band diagrams, carrier distributions in the active region, and electron leakage current are given and the simulation results show that the proposed lattice-compensated superlattice-AlGaN/InGaN EBL can provide better optical and electrical output performances when compared to the conventional rectangular AlGaN EBL. The output power of the green LED can be enhanced by a factor of 52% and the applied voltage can be reduced from 5.08 V to 4.53 V at an injection current of 1500 mA. The internal quantum efficiency is improved and the percentage of the efficiency droop can also be reduced from 58% to 37%, which is mainly attributed to the successful suppression of electron leakage current and improvement in hole injection efficiency.