Demonstration of ultra-small (＜10 μm) 632 nm red InGaN micro-LEDs with useful on-wafer external quantum efficiency (＞0.2%) for mini-displays

摘要

Ultra-small red micro-LEDs (mu m) with measurable output power have proved difficult to demonstrate. The smallest state-of-the-art red micro-LEDs (AlInGaP) to have exhibited a decent output power of similar to 1.75 mW mm(-2) are 20 mu m x 20 mu m in dimension. InGaN-based red micro-LED development has primarily been impeded due to the large lattice mismatch between the substrate and the quantum wells along with fabrication challenges such as low damage etching. In this work, we demonstrate 6 mu m x 6 mu m sized InGaN red micro-LEDs with an on-wafer external quantum efficiency of 0.2% and light output power reaching 2.1 mW mm(-2).