Efficiency enhancement of submicron-size light-emitting diodes by triple dielectric layers

Micro-LED (light-emitting diode) is an emerging technology that produces superiorly bright, efficient, and high-resolution display. However, efficiency drop at small chip sizes is one of the major hurdles for cost-effectiveness and ultra-compact form factor. We demonstrate highly efficient submicron-scale nanorod LEDs (nLEDs) passivated by the triple dielectric layers. The diameter, length, and wavelength at a peak external quantum efficiency (EQE) of nLEDs are 580 nm, 5 μm, and 460 nm, respectively. We report a peak EQE of 22.2 ± 0.3% with HfO₂-based triple dielectric layer. We also explore the relation of indium fluctuation in multi-quantum wells (MQWs) to sidewall effect of micro-LEDs. We show that higher indium contents in MQWs successfully reduce non-radiative recombination on sidewall of InGaN blue nLEDs.