Enhancing the Efficiency of Green micro-LEDs by Optimizing p-Electrode Contact Area Ratios

Considering the low electrical conductivity of the p-type contact layer, current crowding is the primary impediment to the preparation of gallium nitride green micro-light-emitting-diodes (micro-LEDs). In this study, the effects of different p-electrode contact area ratios on the photoelectric characteristics of green micro-LEDs were investigated. We demonstrated that appropriately increasing the p-electrode contact area ratio improves the photoelectric performance of green micro-LEDs, including the dynamic resistance, electroluminescence (EL) intensity, light output power (LOP), wall-plug efficiency (WPE), and external quantum efficiency. Microscopic hyperspectral imaging ( $\mu $ -HSI) revealed that optimizing the p-electrode contact area ratio promotes current spreading and improves the uniformity of luminous distribution on chip surfaces. The Comsol Multiphysics simulation shows the distribution of current density at four kinds of contact area ratios. The green micro-LEDs with p-electrode contact area ratios of 30% demonstrated the best photoelectric performance and uniform luminous distribution.