High-Power, Low-Efficiency-Droop Semipolar (20(2)over-bar(1)over-bar) Single-Quantum-Well Blue Light-Emitting Diodes

We demonstrate a small-area (0.1mm(2)) semipolar (20 (2) over bar(1) over bar) blue (447 nm) light-emitting diode (LED) with high light output power (LOP) and external quantum efficiency (EQE) by utilizing a single 12-nm-thick InGaN quantum well. The LED had pulsed LOPs of 140, 253, 361, and 460mW, and EQEs of 50.1, 45.3, 43.0, and 41.2%, at current densities of 100, 200, 300, and 400 A/cm(2), respectively. The device showed little blue shift and had a narrow full width at half maximum (FWHM). Micro-electroluminescence (mu-EL) and scanning transmission electron microscope (STEM) images indicate a high-quality InGaN quantum well (QW) layer. (C) 2012 The Japan Society of Applied Physics