Impact of Mg-Doped AlGaN Electron Blocking Layer on Micro-LEDs: A Comparative Analysis of Carrier Transport Versus Chip Size and Current Density

Abstract

Micro-light emitting diode (micro-LED) is an essential component for the next-generation self-emissive display. However, existing studies often focus on specific parameters, such as chip size and current density, which restricts the overall understanding of micro-LEDs. This study presents a novel and extensive numerical analysis evaluating the impact of Mg-doped AlGaN electron blocking layers (EBLs) on InGaN-based micro-LED performance, covering current densities from 0.1 to 1000 A/cm2 and mesa sizes from 3 to $100~\mu $ m for micro-LEDs to $\gt 200~\mu $ m for conventional LEDs. Unlike prior studies, our work uniquely investigates the interplay between EBL doping concentrations and micro-LED performance across multiple dimensions, providing new insights into carrier injection mechanisms. By varying the EBL doping levels ( $1\times 10^{{19}}$ cm−3, $3\times 10^{{18}}$ cm−3, and without EBL), we explored their impact on the band alignment at the last quantum barrier (LQB) and EBL interface, which is crucial for modulating carrier injections and increasing light output power density (LOPD). The results indicate that optimizing EBL properties improves electron blocking at low current densities and enhances hole injection at higher densities, effectively reducing the current leakage and enhancing the luminous efficiency of micro-LEDs across a broad range of current densities. This comprehensive analysis challenges conventional micro-LED design approaches by emphasizing the importance of EBL engineering to achieve balanced and efficient carrier injections under a variety of operating conditions, providing a pathway for future innovations in micro-LED technology.