Black phosphorus mid-infrared light emitting diodes integrated with silicon photonic waveguides.

Light-emitting diodes (LEDs) based on III-V/II-VI materials have delivered a compelling performance in the mid-infrared (mid-IR) region, which enabled wide-ranging applications in sensing, including environmental monitoring, defense, and medical diagnostics. Continued efforts are underway to realize on-chip sensors via heterogeneous integration of mid-IR emitters on a silicon photonic chip, but the uptake of such an approach is limited by the high costs and interfacial strains, associated with the processes of heterogeneous integrations. Here, the black phosphorus (BP)-based van der Waals (vdW) heterostructures are exploited as room-temperature LEDs. The demonstrated devices emit linearly polarized light, and the spectra cover the technologically important mid-IR atmospheric window. Additionally, the BP LEDs exhibit fast modulation speed and exceptional operation stability. The measured peak extrinsic quantum efficiency is comparable to the III-V/II-VI mid-IR LEDs. By leveraging the integrability of vdW heterostructures, we further demonstrate a silicon photonic waveguide-integrated BP LED.