Optimization of Device Structures for Bright Blue Semipolar (10(1)over-bar(1)over-bar) Light Emitting Diodes via Metalorganic Chemical Vapor Deposition

The device structures of semipolar (10 (1) over bar(1) over bar) GaN blue light emitting diodes (LEDs) were optimized to achieve high power and high efficiency via metalorganic chemical vapor deposition (MOCVD). The quantum well (QW) width, barrier thickness and last barrier (LB) thickness were varied in order to optimize device performances and achieve the best growth conditions. Additional optimization methods such as Mg doping for the LB and p+ contact layers were also investigated. This study resulted in a LED with an output power of 22.75 mW and an external quantum efficiency (EQE) of 39.5% at a driving current of 20 mA, which is a significant improvement over previous results. (C) 2010 The Japan Society of Applied Physics