A facile method to fabricate a novel 3D porous silicon/gold architecture for surface enhanced Raman scattering

Si-based surface enhanced Raman scattering (SERS) sensing technology is a powerful tool for the detection of various chemical and biological species. Further improvement of the simplicity, stability, sensitivity, and low cost of Si-based SERS platforms is still in great demand for real applications. In this study, the facile fabrication of three-dimensional (3D) porous Si/Au SERS platform with attractive SERS performances was reported. The developed method relied on laser-induced dendrite-like microstructure on the surface of Al-Si cast alloy followed by dealloying Al from the laser treated surface, leaving a 3D dendrite-like porous Si substrate. By sputtering, the substrate was coated with Au film to form 3D porous Si/Au SERS platform. Such 3D porous Si/Au SERS platform had high SERS sensitivity that enabled ultralow concentration detection of R6G molecules down to 10⁻¹⁵ M with enhancement factor in the range of 10¹¹ to 10¹². The relative standard deviation of 6.2% was obtained from 15 random SERS spectrum, indicating superior reproducibility of the as-fabricated 3D porous Si/Au SERS platform.