Competitive mechanism between light extraction efficiency and sidewall passivated effect in the green micro-LEDs with varied thickness of Al₂O₃ layer

In this study, green micro-light-emitting diodes (<i>μ</i>-LEDs) with Al₂O₃layers of varying thicknesses (0, 30, 60, and 90 nm) was fabricated using atomic layer deposition (ALD) technology. The optoelectronic characteristics of devices was measured and investigated. Current-voltage (<i>I</i>-<i>V</i>) measurements indicate that the ALD passivation layer effectively reduces leakage current. By applying the<i>ABC + f(n)</i>model to analyze external quantum efficiency, the internal physical mechanisms that the ALD passivation layer enhances the optoelectronic performance of green<i>μ</i>-LEDs was identified. Optical simulations demonstrated the transmittance relationship for different ALD passivation layer thicknesses, explaining improvements of light extraction efficiency. Furthermore, aging tests confirmed that the ALD passivation layer significantly increases the stability of green<i>μ</i>-LEDs. These findings offer valuable insights for enhancing the luminous efficiency and reliability of green<i>μ</i>-LEDs.