Broadband and high-speed terahertz wireless sensing via vertical-transport Dirac-source detector

In the realm of wireless sensing, it is envisioned that sensing and communication functionalities will coexist and be fully integrated within a unified system. Future sensing systems thus necessitate detectors capable of operating at higher frequency bands—ranging from millimeter wave to terahertz (THz)—while delivering wider bandwidths, faster response rates, and enhanced functional integration. Dirac-source (DS) detectors use Dirac semimetals as hot-electron sources to capitalize on the low density of states (DOS) near the Dirac point, thereby effectively suppressing the formation of metal-induced gap states. Furthermore, when this architecture incorporates the inherent interlayer vertical electron transport of vertical van der Waals (vdW) heterostructures, it shows great promise for realizing low-power, post–Moore era sensing devices with superior injection and transport efficiencies. Here, we report a DS detector composed of the completely vertical gold/zirconium pentatelluride/graphene/gold structure (Au/ZrTe 5 /graphene/Au) heterojunction, which harnesses strong localized fields to achieve high thermionic emission. The detector manifests outstanding performance in terms of remarkable responsivity, exceeds a peak of 1600 V/W from 0.02 to 0.5 THz at room temperature, has a fast response time less than 20 ns, and notably is capable for heterodyne mixing with intermediate frequency (IF) bandwidth larger than ±26.5 gigahertz. Our results not only shed a fresh light on DS dynamics in the terahertz region but also highlight the transformative potential of semimetal electronics for applications in wireless energy harvesting, communication, and imaging.