In-Depth Investigation of Deep Ultraviolet MicroLED Geometry for Enhanced Performance

In this work, we demonstrate a straightforward and effective strategy, so called perimeter-to-area ratio (P/A ratio) engineering, to enhance the optical performance of deep-ultraviolet micro-scale LED (DUV $\mu $ -LEDs). Specifically, we designed and fabricated three types of DUV $\mu $ -LEDs architectures with circle, pentagon, and quadrangle shapes which possess different P/A ratios, and found that the external quantum efficiency (EQE) of the quadrilateral $\mu $ -LEDs exhibit the highest value thanks to its largest P/A ratio in the LED mesa covered by the p-electrode, leading to a higher light output power than that of $\mu $ -LED in circle shape by 29.2% at an injection current density of 3000 A/cm $^{\mathbf {{2}}}$ . More importantly, such superior performance due to the increased P/A ratio of $\mu $ -LEDs is becoming more remarkable when the size of $\mu $ -LEDs further shrinks, attributing to a larger light extraction, more uniform current spreading, and better sidewall out-radiation of self-generated heat of the $\mu $ -LEDs.