Near-field THz photocurrent nanoscopy of InAs nanowires FET

The increasing interest in manipulating electromagnetic waves in the terahertz (THz) spectral range has motivated, in the last decade, a great research effort in the development of miniaturized technologies for THz emission and detection. Recently, field effect transistors (FETs), exploiting semiconductor nanowires (NWs) as active element, have been proven successful in highly-sensitive room-temperature detection of THz frequency beams. The FETs act as rectifiers converting the impinging THz radiation into a DC signal between source (S) and drain (D), proportional to the absorbed power and controlled by the gate (G) bias. The THz-detection with the NW either exploits the photo-excitation of plasma waves [1], or, thermoelectric phenomena [2].