Double quantum dots as a high sensitive submillimeter-wave detector

A single-electron transistor (SET) consisting of parallel double quantum dots fabricated in a GaAs/AlxGa1−xAs heterostructure crystal is demonstrated and it serves as an extremely high sensitive detector of submillimeter waves (SMMWs). One of the double dots is ionized by a SMMW via Kohn-mode plasma excitation, which affects the SET conductance through the other quantum dot, yielding the photoresponse. The noise equivalent power of the detector for wavelengths of about 0.6 mm is estimated to reach the order of 10−17 W/Hz at 70 mK.