Planar Zn metasurfaces formed through localized O2 plasma treatment for optically transparent RF shielding

Electromagnetic interference (EMI) shielding is usually achieved using metallic films and foils. However, those approaches lack the optical transmission which is desirable in various technologies. Here, a novel performance coefficient has been introduced to quantify the trade-off between Vis-IR and RF performance. Metasurfaces are an effective way of balancing optical transmission and EMI shielding, and finite-element and finite-difference simulations are employed to determine the optimized metasurface geometry for specific metallic sheet resistance. The results are implemented experimentally in a Zn/ZnO metasurface. RF magnetron sputtering conditions have been optimized to reduce the sheet resistance of Zn to 5 Ω/Υ. An O 2 plasma treatment is applied to convert an opaque Zn film into a transparent ZnO film across the Vis, IR, and RF regimes. The metasurfaces are fabricated using e-beam lithography and subsequent localized oxidation of the Zn film. The resulting metasurfaces exhibit high planarity, Vis-IR transmission values above 50%, and shielding effectiveness values exceeding 10 dB in the S-band. This approach can be applied to a range of metasurface structures, enabling the creation of high-performance coatings.