High-Power Blue-Violet Semipolar ($20\bar{2}\bar{1}$) InGaN/GaN Light-Emitting Diodes with Low Efficiency Droop at 200 A/cm$^{2}$

Abstract

We report a high-power blue light-emitting diode (LED) with a high external quantum efficiency and low droop on a free-standing (20 ) GaN substrate. At a forward current of 20 mA, the LED showed a peak external quantum efficiency of 52% and an output power of 30.6 mW. In higher current density regions, the LED also showed outstanding performance, with droop ratios of 0.7% at 35 A/cm², 4.3% at 50 A/cm², 8.5% at 100 A/cm², and 14.3% at 200 A/cm². The output power and external quantum efficiency at 200 A/cm² were 266.5 mW and 45.3%, respectively.