Light rectification with plasmonic nano-cone point contact-insulator-metal architecture

Abstract

Numerous efforts have been recently undertaken towards the development of rectifying devices operating at high frequencies especially dedicated to light harvesting and photo detection applications. To this end various rectification strategies have been implemented, such as laser-induced STM tunneling, metal-insulator-metal (MIM) travelling wave diodes, plasmonic nanogap optical antennas, antenna-diode coupled planar MIM, and MIM point-contact sharp-tip or whisker diodes. However, developing high frequency rectifying antennas (rectennas) remains a major technological challenge, as only recent progresses enabled the fabrication of efficient tunable nano-antennas at near infrared and visible frequencies. Here we report on a new type of rectenna based on plasmonic carrier generation. The proposed rectifying structure consists of a broadly resonant gold conical nano-tip antenna in contact with a metal-oxide/metal sample surface, forming a point-contact tunneling diode. The nano-sized antenna apex, designed to maximize the Surface Plasmon Polaritons (SPPs) damping, allows for an efficient power conversion from the light field into excited charges above the Fermi level, the latter ones collectable from the point-contact location through an electronic tunneling process. We demonstrated rectification operation at 280 THz with a power conversion efficiency one order of magnitude higher than the state-of-the-art which we attribute to efficient plasmonic carrier generation and collection.