Improved Optoelectronic Performance of High-Voltage Ultraviolet Light-Emitting Diodes Through Electrode Designs

High-efficiency high-voltage ultraviolet light-emitting diodes (HV-UVLEDs) consisting of a 4 x 4 microcells array with an area of 61 mil x 33 mil were designed and fabricated via the electrode pattern and interconnect technique. Polymer material was used to fill trench with planarization, and interconnection technology was used for metal layer connection to address wiring defect issue. In comparison with the conventional lateral UV-LED (C-UVLED), which had 33.6% and 34.7% enhancement in the light output power and wall-plug efficiency (at 1.5 W) of the HV-UVLEDs. A 56% improvement in the external quantum efficiency droop behavior was achieved for the HV-UVLEDs when compared with that of C-UVLED. This improvement can be attributed to superior current spreading in the HV-UVLED due to its smaller microcells, which increases light-emission efficiency overall.