Ricerc@Sapienza

CMOS technology has been extensively used for the realization of image sensors at Terahertz frequencies. The explanation of its strong efficiency was usually given invoking a mechanism described by the plasma wave detection theory. This model predicts that, when a high frequency potential is applied between gate and source electrodes of a MOSFET, oscillations of the 2D electron gas, located in the inversion layer, converts THz radiation into a DC voltage.

We present a new solid state rectifier, compatible with CMOS integrated circuit, suitable to direct conversion of terahertz radiation, at room temperature. The structure creates a rectenna, consists in a truncated conical helix extruded from a planar spiral and connected to a nanometric metallic whisker at one of its edges. The whisker reaches the gate of a MOS-FET transistor. Rectification can be obtained by the self-mixing effect occurring into the plasma waves generate underneath the gate. The proposed solution is easy to integrate with existing imaging systems.