Efficiency and Electron Leakage Characteristics in GaN-Based Light-Emitting Diodes Without AlGaN Electron-Blocking-Layer Structures

The authors investigate efficiency and electron leakage characteristics in GaN-based light-emitting diodes (LEDs) without AlGaN electron-blocking-layer (EBL) structures. Both simulation and electroluminescence (EL) measurement results show that the internal quantum efficiency decreases rapidly as the thickness of an undoped GaN interlayer between active layers and a p-GaN layer increases, which is caused by electron leakage from active layers to the p-GaN due to inefficient hole injection. However, photoluminescence (PL) measurement results show that the quality of active layers deteriorates as the interlayer thickness decreases. The EL and PL results imply that the optimization of the undoped GaN interlayer thickness is important for achieving high internal quantum efficiency in AlGaN-EBL-free LEDs.