Mie‐Resonant Metasurfaces with Controlled Silicon Oxidation in Electron‐Beam Deposition

Abstract Electron‐beam deposition stands as a versatile technique utilized for the accurate and controlled thin‐film deposition of a wide range of materials that readily undergo evaporation. However, silicon, a commonly used material, is prone to oxidation during the deposition process because of the presence of water vapors and oxygen in the chamber. To overcome this challenge, a tailored approach is developed that involves controlling the deposition conditions, including the base pressure in the chamber and the deposition rate. Silicon oxidation is successfully overcome, and this results in achieving refractive index values comparable to those obtained with alternative deposition methods for amorphous silicon. The research shows that the deposition conditions can be utilized effectively to tune the refractive index, providing flexibility in achieving the desired optical properties. It is demonstrated that Mie‐resonant metasurfaces exhibit strong collective resonances, driven by the coherent coupling of Mie modes within the periodic nanoantenna lattice, as evidenced by distinct spectral features in the scattering response. These resonances are observed to be highly tunable, with spectral shifts corresponding to controlled variations in the electron‐beam deposition parameters and silicon oxidation. The approach enables silicon deposition for metasurfaces, which presents exciting possibilities for tailoring and designing advanced nanostructures with unique optical characteristics.