Recent Progresses on InGaN Red Micro-Leds for Display

Micro-scale light-emitting diodes (micro-LEDs), with their high brightness, high resolution, and low power consumption, are emerging as a promising candidate for the next-generation display. Among them, InGaN red micro-LEDs, as a crucial component of full-color micro-displays, have attracted significant attention for their smaller size effect, higher thermal stability, and compatibility with blue and green micro-LED fabrication processes and so on, when compared to AlGaInP red micro-LEDs. However, for next-generation display technologies such as augmented reality (AR), InGaN red micro-LEDs still fall short of meeting the requirements. Specifically, the efficiency of InGaN red micro-LEDs with the ultra-small size needed for AR applications is still very low, necessitating a high working current density. Unfortunately, a high current density leads to a significant blueshift in the emission wavelength, which results in color deviation, failing to meet the requirements for red display devices. This review has introduced two approaches to address the aforementioned issues, namely enhancing the efficiency of InGaN red micro-LEDs or suppressing the blueshift, and has listed the performances of recent typical InGaN red micro-LEDs. Finally, the potential of InGaN red micro-LEDs in the full-color monolithic displays has been discussed.