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 semi conductors (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 100 V IW, with impressive noise equivalent power levels < 6 x 10-11W/Hz at room temperature and a > 300kHz 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.
We report about fabrication and characterization of semiconductor nanowire-based field effect transistor devices
which can act as detectors for electromagnetic radiation in the THz frequency range. The detection mechanism
is based on the nonlinear transfer characteristic of the transistor, which is used to realize signal rectification; the
small capacitance related to the nanowire small cross section is beneficial in allowing a good device sensitivity
up to 1.5 THz at room temperature. Due to the extreme flexibility with which semiconductor nanowires can be
grown, we discuss how the basic, homogeneous InAs or InSb nanowire FETs can be improved to realize smarter
devices and functionalities.