Quasi-free standing epitaxial silicon carbide-based room–temperature heterodyne terahertz detector

Ultrafast and sensitive detection in the THz range is important for spectroscopy of gases, complex molecules, and imaging metrology. Hot carriers in graphene are thermally decoupled from crystal lattice due to slow electron-lattice relaxation. The hot carrier regime thus gives rise to a strong thermoelectric effect. In this work, we utilize the thermoelectric response of quasi-free standing epitaxial graphene on silicon carbide to design a THz detector. The graphene in our device is coupled to a patch antenna resonant at 650 GHz. The device is integrated with a silicon lens to focus the THz source on the device. The patch antenna in our device not only couples the resonant THz radiation on graphene but also is utilized to tune the p-n junction of graphene for a maximum thermoelectric response. We demonstrate a room-temperature heterodyne mixing-based THz detection and report the noise equivalent temperature (NEP) of our detector.