Performance improvements in InGaN/GaN light-emitting diodes using electron blocking layer with V-shaped graded Al composition

Abstract

In this study, AlGaN electron blocking layers (EBLs) with graded Al compositions have been numerically investigated to improve hole injection and electron confinement in InGaN/GaN-based light-emitting diodes (LEDs). Compared to LEDs with reference structure the output power of the proposed LEDs with decreasing/increasing (V-shaped) grading of the Al composition along the EBL growth direction was increased by a factor of similar to 2.5, whereas the efficiency droop at high currents was greatly reduced. In addition, the forward voltage was reduced from 3.69 V to 3.42 V at 20 mA. These results indicate that well-designed EBLs using a V-shaped graded Al composition can enhance hole injection and electron confinement by reducing the polarization effect in these devices. (C) 2014 Elsevier Ltd. All rights reserved.