Efficiency droop of AlGaN-based deep-ultraviolet miniaturized light-emitting diodes under electrical stress

The reduction on efficiency of AlGaN-based high-voltage (HV) deep ultraviolet light emitting diodes (DUV-LEDs) with quadra-serial connection and different geometries has been investigated under electrical stress. After the electrical aging, the Shockley–Read–Hall nonradiative recombination becomes more significant, while the Auger recombination is mitigated. The hexagonal HV DUV-LEDs reach a maximum external quantum efficiency of 6.1% and exhibit superior performance after aging. The results provide insights into the impacts of submesa geometry on reliability and UV light communication performance of HV DUV-LEDs.