Demonstration of InGaN Micro-Light-Emitting Diodes with Long Wavelength Emission Based on GaN Substrate

With the growing demand for full-color micro-displays in augmented reality (AR) and virtual reality (VR) applications, InGaN-based red micro-LEDs have been attracted a lot of attention from researchers. However, achieving high luminous efficiency of InGaN-based red micro-LEDs remains to be a challenge. In this study, InGaN-based amber micro-LEDs were fabricated using freestanding GaN substrates (FGS). Without intentional optimization of the fabrication process, we achieved a 10 μm micro-LED with a peak external quantum efficiency (EQE) of 0.62% at a current density of 50 A/cm², which is three times that of heteroepitaxial under the same conditions. Additionally, homoepitaxial micro-LEDs demonstrated lower leakage levels. These findings suggest that FGS-based micro-LEDs represent a promising approach for realizing high performance of InGaN-based micro-LEDs with longer wavelength.