Fabrication of Flexible Sticker of Si Metasurfaces by a Transfer Process

Abstract

Periodic arrays of silicon nanoparticles work as metasurfaces to control light at the interface. Although the combination of a variety of functional materials with metasurfaces should open a rich scientific research field, the application degree of freedom is limited severely by the fabrication process. We have developed a transfer process of silicon metasurface that uses a metallic chromium thin film as a sacrificial layer. The array of silicon nanoparticles is fabricated on the chromium thin film via electron-beam lithography and reactive ion etching. Then the metasurface is coated with a polydimethylsiloxane (PDMS) film and the successive dissolution of the chromium layer by an acidic solution results in the self-standing sticker embedding the metasurface. The metasurface sticker shows the optical diffraction behavior predicted from the periodicity of the array, and the transfer is performed without disturbing the periodicity. The sticker is flexible and can be attached to any clean surfaces without special surface treatment. We combine the silicon metasurface sticker with an emitter layer to control the light emission through the sticker. This result extends the application area of the metasurface.