Enhanced electroluminescence in 405 nm InGaN/GaN LEDs by optimized electron blocking layer

In this work, we have investigated the effect of AlGaN electron blocking layer (EBL) doping level and thickness on the optical properties of near-UV (405 nm) InGaN/GaN multiple quantum well (MQW) light emitting diodes (LEDs) grown by metal organic chemical vapor deposition (MOCVD). Photoluminescence (PL) and electroluminescence (EL) of LEDs with a 50-nm-thick undoped GaN spacer layer between the EBL and the MQW stack were systematically studied. We will present evidence showing that the optimal EBL doping and thickness has an important role in the optimization of near-UV LED output power. By employing the optimized EBL structure we were able to enhance the EL intensity by a factor of five compared to the similar structure without the EBL. (c) 2008 Elsevier B.V. All rights reserved.