Frequency-selective and geometrically tunable terahertz detection using Tamm cavity-coupled Si-MOSFETs

Silicon field-effect transistor (FET) terahertz detectors based on plasma-wave rectification have achieved high room-temperature sensitivity in the overdamped, non-resonant regime. However, this operating mode is intrinsically broadband and lacks spectral selectivity, while resonant and tunable plasma-wave detection remains difficult to realize at room temperature because of strong plasma-wave damping. Here, we demonstrate an alternative approach that overcomes this limitation by combining non-resonant plasma-wave detection with electromagnetic field engineering. A high-sensitivity silicon metal–oxide–semiconductor field-effect transistor detector is integrated into a hybrid Tamm cavity, which enhances and spatially confines the terahertz electric field at the transistor channel. This architecture yields a several-fold increase in responsivity and a reduced noise-equivalent power compared to the standalone device. More importantly, the cavity imposes a high-quality-factor spectral selectivity on the intrinsically broadband detector, effectively decoupling detection efficiency from spectral selectivity. We further show that the detection frequency can be tuned by varying the cavity geometry through adjustment of the separation between the detector and the Bragg reflector, enabling a geometrically controlled and reconfigurable spectral response. These results establish hybrid Tamm cavity-coupled silicon FET detectors as a platform for room-temperature terahertz detection that simultaneously provides high sensitivity, spectral selectivity, and tunability, thereby overcoming a long-standing trade-off in plasma-wave terahertz detection.