Effect of EBL thickness on the performance of AlGaN deep ultraviolet light-emitting diodes with polarization-induced doping hole injection layer

Numerical simulation results reveal that introducing polarization-induced doping hole injection layer (HIL) in the DUV-LEDs results in a downward band-bending at the EBL/HIL interface, which causes more severe electron leakage. The effect of optimizing EBL thickness on the performance of DUV-LEDs was investigated to mitigate the side-effects due to the introduction of polarization -induced doping HIL. The experimental results show that as the EBL thickness increases, the external quantum efficiency (EQE) and wall-plug efficiency (WPE) of the DUV-LEDs increase and then decrease, while the efficiency droop in an opposite trend. The maximum EQE and WPE of 5.95% and 5.48%, respectively, were achieved when the EBL thickness was 20 nm. Meanwhile, increasing the EBL thickness can improve the DUV-LED reliability. However, an excessively thick EBL will deteriorate the reliability due to generating more Joule heat. Therefore, the reliability of DUV-LED was optimal when the EBL thickness was 25 nm.