Effect of Green Quantum Well Number on Properties of Green GaN-Based Light-Emitting Diodes**Supported by the National Key Research and Development Program of China under Grant No 2016YFB0400601, and the National Natural Science Foundation of China under Grant Nos 61704069, 11674147, 61604066, 51602141 and 11604137.

Abstract

InGaN-based green light-emitting diodes (LEDs) with different green quantum well numbers grown on Si (111) substrates by metal organic chemical vapor deposition are investigated. It is observed that V-shaped pits appear in the AFM images with the green quantum well number increasing from 5 to 9, and results in larger reverse-bias leakage current. Meanwhile, in the case of the sample with the number from 5 to 7 then to 9, the external quantum efficiency increases firstly, and then decreases. These phenomena may be related to the size of V-shaped pits in the active area and the distribution of electrons and holes in the active area caused by V-shaped pits. The optimal number of green quantum wells is determined to be 7.