Enhancement of performance of GaN-based light-emitting diodes by insertion and optimization of n-InGaN/GaN composite current-spreading layers

Abstract

Si-doped n-InGaN/GaN composite current-spreading layers (CCSLs) inserted between the n-GaN layer and the InGaN/GaN multiple-quantum-well (MQW) active region were developed and optimized for the GaN-based light-emitting diodes (LEDs). It was found that with the optimized n-InGaN/GaN CCSLs lightly doped with Si, the crystalline quality as well as the electric and optical properties of the GaN-based LEDs, such as forward voltage Vf, photoluminescence (PL) intensity, and electrostatic discharge (ESD) endurance could be significantly improved. In particular, an ESD pass yield as high as 99.49% at a 2000 V reverse bias has been achieved for the GaN-based LEDs with the 70 nm/70 nm n-InGaN/GaN CCSLs. This means that the n-InGaN/GaN CCSLs with carefully optimized layer thickness could play a key role in improving the crystalline quality and enhancing the device performance of the GaN-based LEDs.