Characterization of unipolar nanorectifiers coupled with an RF antenna

A novel type of unipolar nanodiode, the self-switching diode (SSD), has recently shown promising properties as an ultra-high-speed detector at room temperature by the utilization of its nonlinear diode-like behavior and intrinsically low parasitic capacitance. In this report, a large SSD array with approximately 2,000 SSDs connected in parallel within the fingers of an interdigital structure was coupled with a printed-circuit-board- (PCB-) based wideband patch antenna, operating in the radio-frequency (RF) region. Such a large array was realized in a single lithography step without the need for interconnection layers. This allows for a simple, low-cost and reproducible fabrication process. Despite of the large impedance mismatch between the SSD array and the PCB-based antenna, the device was able to detect RF signals transmitted using a network analyzer via another patch antenna at distance of approximately 70 cm from it, at 2.45 GHz. The estimated room-temperature extrinsic voltage responsivity of the device and its noise-equivalent power, measured at 5 cm away from the transmitted RF signals and at zero bias, were 10 mV/mW and 1.2 nW/Hz^1/2, respectively. The results have shown that the SSDs can be utilized in many RF applications at low cost.