Enhanced linear polarization of GaN-based Micro-LED via rational chip sidewall engineering

Micro-light-emitting diodes (Micro-LEDs) are considered as the most promising display technologies, while 3D display can provide users with an immersive visual experience and represents the cutting-edge display technology. Polarized Micro-LEDs can be used for polarization-based 3D display technology. In our previous work, circularly polarized and linearly polarized Micro-LEDs have been reported, yet the extinction ratio (ER) still needs to be further improved. The high proportion of sidewalls emission of Micro-LED hinders the further improvement of polarization. In this work, we numerically and experimentally investigated an improved linearly polarized Micro-LED via rational sidewall engineering. Our results show that, at a current density of 300 A/cm2, ER of Micro-LED with a sidewall reflector (RLP Micro-LED) for chip diameters of 10, 20, 30, and 40 μm is 15.85, 16.09, 16.20, and 16.21 dB, respectively, demonstrating a 29.38%, 21.56%, 18.9%, and 12.08% increment compared with linearly polarized Micro-LED without reflector (LP Micro-LED). We also found that by adjusting the sidewall tilt angle, the polarization efficiency and ER values of RLP Micro-LED can be further improved. Our study should advance the development and application of Micro-LED, especially for 3D Micro-LED displays.