Exploring the Influence of Localized Surface Plasmon and Sol–Gel Passivation on Blue InGaN/GaN Micro/Nano Light Emitting Diodes

Abstract

Micro light-emitting diodes (μLEDs) and nano LEDs (nLEDs) are attracting considerable interest as potential candidates for next-generation displays. However, both μLEDs and nLEDs encounter the major challenge of decreasing the external quantum efficiency (EQE) as their size diminishes. To address this issue, this study explores the effect of localized surface plasmon (LSP) and sol–gel passivation on the performance of blue μLEDs and nLED arrays. The nLED arrays are composed of several nLEDs and are designed to have the same chip area as the μLEDs. The nLED arrays have a larger surface-to-volume ratio compared to μLEDs, resulting in lower efficiency due to effects such as surface recombination. However, the nLED allows Ag/SiO₂ nanoparticles to be positioned in proximity to the sidewalls where the multi-quantum wells are exposed and has an advantage in maximizing the LSP coupling effect and enhancing the impact of sol–gel passivation. As a result, when both effects are applied, the EQE values increased from 3.47%–7.02% to 5.64%–8.08% for μLEDs and from 1.29%–5.22% to 4.90%–9.60% for nLEDs, as the size increases from 10 to 50 μm. Specifically, the EQE enhancement resulting from the application of the LSP coupling effect in nLEDs ranges from 50%–200%, which is significantly higher compared to μLEDs. The proposed approach provides insights into the influence of the LSP coupling effect combined with sol–gel passivation on enhancing the efficiency of μLEDs and nLEDs for next-generation displays