Performance Improvement of InGaN Red Light‐Emitting Diode by Using V‐Pits Layer and Step‐Graded GaN Barrier

Abstract

The carrier‐transport properties of InGaN red light‐emitting diode (LED) with V‐pits layer and step‐graded GaN barrier are investigated. By using V‐pits layer technology, the inverted pyramid–shaped V‐pit layer forms an energy barrier around the dislocation, inhibits the lateral diffusion of electrons from active layer to the dislocation center, and reduces the probability of non‐radiative recombination rate of electrons and holes. With the increase of the horizontal opening width of the V‐pits layer, the uniformity of holes concentration distribution in InGaN/GaN multiple quantum well (MQWs)‐active region is improved significantly. Compared with the traditional InGaN/GaN MQWs‐active region with fixed well/barrier thickness, step gradient GaN barrier is adopted in the active layer of InGaN red LED, which can reduce the length of the transmission path and improve the injection efficiency of holes into deep quantum wells close to the n‐type region. At injection current density of 200 A cm−2, the internal quantum efficiency of LED D with V‐pits layer and step‐graded GaN barrier is improved by 56.4% as compared with that of reference LED A. In addition, the efficiency droop of LED D can also be effectively alleviated as compared with that of reference LED A.