High-Efficiency Single-Quantum-Well Green and Yellow-Green Light-Emitting Diodes on Semipolar ($20\bar{2}1$) GaN Substrates

We demonstrate high-efficiency green and yellow-green single-quantum-well light-emitting diodes (LEDs) grown on semipolar ($20\bar{2}1$) GaN substrates by metal organic chemical vapor deposition. The output power and external quantum efficiency at a driving current of 20 mA under a pulsed condition with a 10% duty cycle are 9.9 mW and 20.4% for the green LED and 5.7 mW and 12.6% for the yellow-green LED, respectively. The electroluminescence linewidth narrowing, which is related to the band-filling effect caused by potential fluctuations, is not observed.