Gold-film coating assisted femtosecond laser fabrication of large-area, uniform surface micro/nanostructures

• 1、Laser Micro/Nano Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081

Abstract：This paper reports a simple, repeatable approach to fabricate large-area, uniform micro/nanostructures by a femtosecond laser. Specially, 20 nm gold films are coated on semiconductor surfaces on which large-area, uniform micro/nanostructures are fabricated by a femtosecond laser. In the case study of silicon, defects and cross-links are significantly reduced in the laser induced surface structures on Au-coated silicon. The good consistency between the scanning lines facilitates the formation of large-area, uniform surface micro/nanostructures. The diffusion of hot electrons in the Au films increases the interfacial carrier densities, which significantly enhances interfacial electron-phonon coupling. High and uniform electron density suppresses the influence of defects on silicon and further makes the coupling field more uniform and thus reduce the impact of laser energy fluctuations, which homogenizes and stabilizes large-area surface micro/nanostructures. In addition, the proposed new approach might exhibit potential applications, especially in the absorption enhancement of materials surfaces, high surface-enhanced Raman scattering and generation of functional surfaces with hydrophobic wetting behaviors.

keywords： femtosecond laser micro/nanostructures Au-coated silicon

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