High-speed sensing of rf signals with phase-change materials

The rf radiation spectrum is central to wireless and radar systems among numerous high-frequency device technologies. Here, we demonstrate sensing of rf signals in the technologically relevant 2.4-GHz range utilizing vanadium dioxide (VO2), a quantum material that has garnered significant interest for its insulator-to-metal transition. We find that the electrical resistance of both stoichiometric as well as off-stoichiometric vanadium oxide films can be modulated with rf wave exposures from a distance. The response of the materials to the rf waves can be enhanced by either increasing the power received by the sample or reducing channel separation. We report a significant ∼73% drop in resistance with a 5μm channel gap of the VO2 film at a characteristic response time of 16μs. The peak sensitivity is proximal to the phase-transition-temperature boundary that can be engineered via doping and crystal chemistry. Dynamic sensing measurements highlight the films' rapid response and broad-spectrum sensitivity. Engineering electronic phase boundaries in correlated electron systems could offer new capabilities in emerging communication technologies.