28.3THz bowtie antenna integrated rectifier for infrared energy harvesting

The design, fabrication and characterization of an asymmetric 28.3 THz antenna integrated rectifier (rectenna) using Au/Al₂O₃/Pt is presented. The rectenna design comprises a sharp tip bowtie antenna and a tunneling Metal-insulator-Metal (MIM) diode. The design benefits from the geometric field enhancement around the nano tips of the bowtie antenna. Simultaneous optimization of the antenna´s length and flare angle resulted in a relative intensity enhancement of 10⁴ for a 10 nm gap. In order to benefit from the field enhancement, the THz diode is realized through the overlap of the bowtie sharp tips exactly at the hot spot. Dissimilar electrodes are used to allow THz signals rectification at zero bias, which is critical for energy harvesting applications. The rectenna exhibits a zero bias responsivity of 10 A/W.