The improvement of deep-ultraviolet light-emitting diodes with gradually decreasing Al content in AlGaN electron blocking layers

Deep-ultraviolet light-emitting diodes (DUV-LEDs) with conventional and specifically designed electron blocking layers (EBLs) are numerical investigated with APSYS simulation program. The results show that the internal quantum efficiency (IQE) and light output power are significantly improved by using a AlGaN EBL with gradually decreasing Al content compared to the conventional EBL with constant Al content and the EBL with gradually increasing Al content. These improvement are mainly attributed to the lower polarization field in EBL and active region as well as the alleviation of band bending in the EBL/p-GaN interface, which lead to less electron leakage and better hole injection efficiency, thus enhance the radiative recombination rate.