Enhancing InGaN LED performance via ALD-grown Al2O3 sidewall passivation

Abstract

InGaN-based light-emitting diodes (LEDs) are at the forefront of solid-state lighting technologies due to their superior efficiency and broad spectral emission. However, their performance is often compromised by leakage currents, which lead to reduced external quantum efficiency. Passivation of surface defect, the need of which arises from either epitaxial growth or mesa etching, emerges as a promising strategy to mitigate leakage currents and enhance LED performance. This study compares the effects of different sidewall passivation using two dielectric materials, Al2O3 and SiO2, on the reliability and long-term stability performance of InGaN LEDs. The study conducts a comprehensive analysis to evaluate the impact of each material on reducing leakage current and improving overall device efficiency. The experimental findings of our study indicate that the LEDs with Al2O3 sidewall passivation have better long-term stability performance, lower series resistance, higher breakdown voltages, significantly lower leakage current, and up to a 19% increase in light output power compared to SiO2 sidewall passivation. These superior properties of Al2O3-passivated LEDs increase device reliability and stability. Conversely, SiO2-passivated LEDs demonstrate relatively higher leakage currents, which can be attributed to lower dielectric constant, non-uniform film deposition and incomplete defect passivation.