Room-temperature nanowire terahertz photodetectors

Semiconductor nanowires (NWs) represent an ideal building block for implementing rectifying diodes or plasma-wave detectors that could operate well into the THz, thanks to the typical attofarad-order capacitance. Despite the strong effort in developing these nanostructures for a new generation of complementary metal-oxide semiconductors (CMOS), memory and photonic devices, their potential as radiation sensors into the Terahertz is just starting to be explored. We report on the development of NW-based field effect transistors operating as high sensitivity THz detectors in the 0 : 3 2 : 8 THz range. By feeding the radiation field of either an electronic THz source or a quantum cascade laser (QCL) at the gate-source electrodes by means of a wide band dipole antenna, we measured a photovoltage signal corresponding to responsivity values up to 100V/W, with impressive noise equivalent power levels < 6 x 10(-11) W/root Hz at room temperature and a >300 kHz modulation bandwidth. The potential scalability to even higher frequencies and the technological feasibility of realizing multi-pixel arrays coupled with QCL sources make the proposed technology highly competitive for a future generation of THz detection systems.