Enhancing WPE for AlGaN-based DUV LEDs using a hybrid heterostructure and recessed electrodes design

One of the key factors limiting the wall-plug efficiency (WPE) of AlGaN-based deep-ultraviolet (DUV) light-emitting diodes (LEDs) is the high voltage drop over the n-contact on the Al-rich n-AlGaN. Here, we have proposed a hybrid scheme of n-AlGaN heterostructure and recessed cathodes to optimize the n-contact. The designed LED with n-Al_0.70Ga_0.30N insertion layer to construct a hetero-structure and proper-depth recess n-electrodes exhibits twice the current density and 38.7% WPE improvement related to the conventional LED. Numerical calculations reveal that the hybrid n-contact structure can enhance electron injection efficiency and radiative recombination efficiency by modulating electron transport processes. This study offers a feasible strategy for AlGaN-based DUV LEDs to reduce electrical turn-on voltage and improve optical efficiency.