Reduction in the Number of Quantum Wells Alleviates the Sidewall Effect in AlGaInP-Based Red Micro-LEDs

Abstract

AlGaInP-based red micro-light-emitting diodes (micro-LEDs) act as promising candidates for red emitters of ultra-high-resolution displays. However, as the size of micro-LEDs decreases, the impact of sidewall defects on the efficiency degradation becomes more pronounced. The reduction in the number of quantum wells (QWs) can alleviate the sidewall effect and increase the external quantum efficiency (EQE) of AlGaInP-based flip-chip red micro-LEDs at a low current density. At 300 K, the maximum EQE of micro-LEDs with 3 pairs of QWs is 1.45 times those with 5 pairs, and a considerable enhancement in sidewall emission has been witnessed according to hyperspectral microscopic imaging. These improvements originate from reduced carrier loss in the sidewall region and enhanced radiative recombination in micro-LEDs with 3 pairs of QWs.