Recent progress of InGaN-based red light emitting diodes

Micro-LEDs have been hailed as the next generation display technology due to the advantages of high brightness, high ambient contrast ratio, and high reliability. The InxGa1-xN material possesses the light emission that covers the entire visible spectrum, facilitating the achievement of red/green/blue micro-LEDs and the monolithically integrated full-color displays. After decades of development, although the efficient InGaN-based blue and green LEDs have been realized, the implementation of efficient InGaN-based red LEDs still face serious hurdles. Achieving red emission requires a higher indium content, but the poor crystal quality of high indium content InGaN grown at low temperatures leads to low efficiency of red LEDs. This review provides the recent progress on the InGaN-based red LEDs, summarizes the new methods employed to improve the quantum efficiency, and compares the performance among various approaches. Finally, the potential of applications of InGaN-based red LEDs in the display have also been discussed.