Micro-LED is a display technology composed of arrays of micron-sized LED light-emitting pixels. It boasts advantages such as self-illumination, high resolution, high brightness, high efficiency, high contrast, low power consumption, high stability, and long lifespan, and is considered a revolutionary new display technology. Controlling the light emission characteristics of Micro-LEDs, such as divergence angle, light emission direction, and polarization, will have important applications in 3D Micro-LEDs and AR displays.
In recent years, Wang Liancheng of Central South University, together with the Institute of Semiconductors of the Chinese Academy of Sciences and the team of Hunan University, has been dedicated to the research of in-situ integrated metasurface optical field modulation Micro-LED devices.
From November 19th to 21st, their related achievements were reported at the 10th International Third Generation Semiconductor Forum (IFWS 2024) held in Suzhou: Through bonding, CMP, and other processes, a vertical structure FP resonant cavity Mini/Micro-LED device was proposed and realized for the first time, reducing the spectral half-width at half-maximum (FWHM) from the conventional 24nm to 15nm, and improving the emission directionality by 16.4% [Applied Physics Letters 121.20 (2022)]; Through in-situ integration of subwavelength metal gratings, a linearly polarized Micro-LED was reported for the first time, with a TM/TE ratio of 6.2 times and an equivalent extinction ratio of 14dB, and the polarization ratio was further improved through the deposition of dielectric films and mirror sidewall engineering [Applied Physics Letters 122.11 (2023); Applied Physics Letters 124.11 (2024)]; A circularly polarized Micro-LED was proposed for the first time, with a transverse electromagnetic reflectivity exceeding 80% and an extinction ratio exceeding 38dB [Optics Letters]. [46.11 (2021): 2666-2669]; First design report of directional light-emitting Micro-LED, achieving high-efficiency wide-angle directional light emission, as well as arbitrary angle light emission and dual-angle directional light emission [Optics Letters 46.14 (2021): 3476-3479].
Figure 1: Schematic diagram of light field-modulated Micro-LEDs (a) linearly polarized Micro-LED; (b) circularly polarized Micro-LED; (c) resonant cavity Micro-LED; (d) directional emission Micro-LED
