High Quantum Efficiency and Low Droop of 400-nm InGaN Near-Ultraviolet Light-Emitting Diodes Through Suppressed Leakage Current

High quantum efficiency and low efficiency droop of 400-nm InGaN near-ultraviolet (NUV) light-emitting diodes (LEDs) are achieved using Al
_0.05
Ga
_0.95
N quantum barriers and 3-nm thin Al
_0.3
Ga
_0.7
N insertion layer on last barrier before p-Al
_0.15
Ga
_0.85
N electron blocking layer. At 100 A/cm
²
, for the fabricated 0.1-mm
²
-size LEDs with special designed barriers, the external quantum efficiency increases from 23.8% to 40.7%, and the efficiency droop ratio decreases from 40.5% to as low as 10.3%, as compared with the conventional NUV LEDs. APSYS simulations reveal that a significant suppressed leakage current is the main reason for the performance enhancement.