Geometric diodes for optical rectennas

Abstract

A new diode called a geometric diode rectifies based on geometric asymmetry of a conducting thin film. The planar structure of the geometric diode provides a low RC time constant (on the order of 10-15 s) that is required for rectenna operation at optical frequencies and a low impedance for efficient power transfer from the antenna. Fabricated graphene geometric diodes show asymmetric DC current-voltage characteristics consistent with Monte Carlo simulations for the devices. Coupled to an antenna to form a rectenna, we demonstrated rectification for 28 THz radiation. The geometric diode rectenna system detectivity is in theory 10 times higher than for a metal-insulator-metal diode operating at 28 THz. Applications for this diode include terahertz-wave and optical detection, ultrahigh speed electronics, and optical power conversion.