Decoupling Analysis of Nonradiative Losses Induced by Structural Design in Green Micro-LEDs

The nonradiative recombination in micro-LEDs (μLEDs) significantly degrades their optoelectronic performance. This study systematically investigates the performance of green μLEDs under different structural designs, defined by modulation of the mesa diameter and adjustment of the electrode coverage ratio. Through a combination of experimental characterization and model fitting, we quantitatively disentangle the contributions of bulk and sidewall defects to nonradiative recombination processes. Our results reveal that as the mesa diameter decreases from 58 to 22 μm, the Shockley–Read–Hall (SRH) recombination coefficient associated with sidewall defects increases by a factor of 2.64, while the nonradiative recombination lifetime decreases significantly from 45.4 to 17.4 ns. Furthermore, while increasing the electrode coverage ratio enhances current spreading, it concurrently amplifies carrier diffusion toward the sidewalls, thereby exacerbating nonradiative recombination. This work establishes a comprehensive theoretical framework for optimizing green μLED structural design, effectively alleviating detrimental effects of nonradiative recombination losses while providing critical guidelines for development of high-efficiency devices.