Design of Directional-Emission GeSn Multi-Quantum-Well Light-Emitting Diodes on Si

Infrared light-emitting diodes (IR LEDs) are critical for various technologies, including communication, sensing, and medical diagnostics. Recent advances have introduced directional emission IR LEDs, which offer superior control over light direction, enhance efficiency, and broaden application scopes. Despite the potential of GeSn-based LEDs for short-wave infrared (SWIR) and mid-wave infrared (MIR) applications due to their CMOS compatibility and direct bandgap, these devices suffer from low directionality and light extraction efficiency. This study proposes a novel approach by integrating a dielectric metasurface with GeSn MQW LEDs to achieve directional light emission. We numerically demonstrate that this integration reduces the full width at half-maximum (FWHM) angle of the far-field emission from 60 to 10 degrees and enhances the emission intensity by a factor of 26 at normal incidence. These improvements suggest that metasurface-integrated GeSn LEDs hold significant promise for applications that require high brightness and precise directionality.