Low-Temperature Characteristics of a Silicon-Based Sub-THz Detector

Characteristics of a silicon-based sub-THz plasmonic detector are studied in a wide range of temperatures down to that of liquid nitrogen. The temperature dependences of the detector’s sensitivity are obtained and its noise characteristics are studied. The frequency dependence of the sensitivity in the range of 70–120 GHz is measured at room temperature, and its maximum of 25 V/W is reached at 96 GHz. The noise equivalent power of the studied detector is estimated by assuming that Nyquist noise is the main source of noise, and the values of this power vary from 2 × 10 −10 W Hz −1/2 at room temperature to 2 × 10 −11 W Hz −1/2 at the temperature of liquid nitrogen. The current–voltage characteristics of the sub-THz detector are studied as well. It is found there is a singularity in the differential resistance and sensitivity that depends on the DC voltage applied during the transition from room to nitrogen temperature.