Abstract
We numerically investigated the performance of N-polar AlGaN-based ultraviolet (UV) light-emitting diodes (LEDs) with different Al contents in quantum wells (QWs) and barriers. We found that N-polar structures could improve the maximum internal quantum efficiency (IQE) and suppress the efficiency droop, especially for deep-UV LEDs. Compared to metal-polar LEDs, N-polar ones retained higher IQE values even when the acceptor concentrations in the p-layers were one order of magnitude lower. The enhanced performance originated from the higher injection efficiencies of N-polar structures in terms of efficient carrier injection into QWs and suppressed electron overflow at high current densities. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement