Significant Quantum Efficiency Enhancement of InGaN Red Micro-Light-Emitting Diodes with a Peak External Quantum Efficiency of up to 6%

We demonstrate a significant quantum efficiency enhancement of InGaN red micro-light-emitting diodes (μLEDs). The peak external quantum efficiency (EQE) of the packaged 80 × 80 μm2 InGaN red μLEDs was largely increased to 6.0% at 12 A/cm2, representing the significant process in exploring the efficiency of InGaN red μLEDs. The improvement of the EQE is attributed to the significant enhancement of the quantum efficiency, which is confirmed by the electron–hole wavefunction overlap in the InGaN quantum well from the band gap simulation and the photoluminescence intensity ratio at room temperature/low temperature. Ultrasmall 5 × 5 μm2 InGaN red μLEDs were also obtained, which show a high peak EQE of 4.5%. This work demonstrates a simple approach to achieving highly efficient InGaN red μLEDs, which are very promising candidates for ultrasmall red μLEDs required by AR/VR displays.