Sidewall Suppression and Top Surface Enhancement of Light Extraction Efficiency in Vertically Stacked Full-Color Micro-LEDs Based on L-Shaped Metal Walls

Journal article, 2025

Micro light-emitting diodes (Micro-LEDs) are regarded as the core of next-generation display technology due to their high brightness and energy efficiency. However, the reduction in the size of Micro-LEDs has led to increased manufacturing challenges and exacerbated issues such as sidewall emission, which hinder the development of high-pixel-density displays. This paper proposes a vertically stacked Micro-LED design based on an L-shaped metal wall structure, aiming to suppress sidewall emission and enhance top light extraction efficiency (LEE). Through parameter scanning, the dimensions of the Micro-LED and the thickness of the epitaxial layer are optimized. Combined with inclined sidewalls and the reflective structure of the L-shaped metal wall, the optical characteristics of red, green, and blue Micro-LEDs are analyzed using ray-tracing simulations. The sidewall emission is significantly reduced (with a maximum reduction of 68.04% compared to vertically stacked Micro-LEDs without metal walls), and top light emission is enhanced (the LEE within ±90° direction for blue, green, and red light increased by 196.18%, 51.69%, and 3.45%, respectively, compared to stacked Micro-LEDs without metal walls). The simulation results demonstrate the potential of the L-shaped metal wall in vertically stacked full-color Micro-LED displays, providing a new approach to suppressing optical crosstalk and improving display performance.