Design of high-voltage deep ultraviolet LED sub-mesas toward improved optoelectronic performance

Here, we systematically investigate the effect of mesa/submesa sidewall engineering on single-junction (SJ) and high- voltage (HV) deep ultraviolet light-emitting diodes (DUV LEDs). The configuration of similar to 46 degrees inclined angle of the mesa/sub-mesa sidewall and Al reflector optimally promotes light extraction of SJ/HV DUV LEDs. We further observe substantial improvements in the self-heating and external quantum efficiency (EQE) droop effects of HV DUV LEDs with an increasing number of sub-mesas. Specifically, the EQE droops are 27.67c and 34.67c for HV DUV LEDs with two and four sub-mesas, respectively, at an input power of 6.4 W. These values are markedly lower than the 51.67c droop observed in the SJ DUV LEDs, which is partly attributed to the superior heat dissipation and light extraction facilitated by a high perimeter-to-area ratio of the sub-mesas. This investigation sheds light on mesa design-related efficiency droop behaviors and contributes to enhancing the optoelectronic performance of AlGaN-based DUV LEDs. (c) 2024 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.