Multiband plasmonic nanoantenna structure for infrared energy harvesting based on electron field emission rectification

Abstract

AbstractIn this article, a multiband, planar, direct energy rectification, and dual polarized infrared plasmonic nanoantenna is presented and numerically simulated using finite element method (FEM). Broadband characteristics are highly suitable for energy harvesting applications. The proposed nanoantenna structure comprises cross bowtie aluminum structures deposited on the silicon dioxide (SiO2) substrate. In the proposed device, incoming thermal electromagnetic energy is first enhanced by micro‐lenses through focusing the thermal energy onto the nanoantenna. Then, further enhancement is achieved using several nanoantennas, each with different resonance length, to achieve enough electrical field for electron field emission from sharp metallic tips in their gaps. Each nanoantenna resonates in the proper wavelength, electrical field is enhanced in the gap, and finally, a total current is generated from electron field emissions. The calculated current, based on Fowler‐Nordheim theory, matches well with the simulation results. The total current of the proposed nanostructure is superposition of the produced current of each nanoantenna. To our best knowledge, this is the first report on a multiband nanostructure for energy harvesting. As a typical implementation, a structure is designed for energy absorption in the mid infrared wavelengths, 1‐4 µm.