Effect of Internal Polarization Fields in InGaN/GaN Multiple-Quantum Wells on the Efficiency of Blue Light-Emitting Diodes

The author theoretically investigates the effects of internal polarization fields on the efficiency of InGaN/GaN multiple-quantum-well (MQW) blue light-emitting diodes (LEDs) based on numerical simulations. Internal quantum efficiency (IQE), current leakage, and carrier distributions are calculated with varying the strength of polarization fields to study the role of the polarization fields on the efficiency characteristics. Simulation results show that, as the strength of the polarization fields increases, electron current leakage from active layers to the p-GaN layer increases and hole concentration distribution at MQWs becomes more inhomogeneous. It is found that these two effects by the internal polarization fields lead to significant decrease in the IQE of InGaN blue LEDs. (C) 2012 The Japan Society of Applied Physics