A 3D-SERS substrate with high stability: Silicon nanowire arrays decorated by silver nanoparticles

Abstract

Stability is an important issue of surface-enhanced Raman scattering (SERS) substrates. In this paper, a highly stable three-dimensional (3D)-SERS substrate has been prepared by surface migration of silver on the surface of silicon nanowires (SiNWs). Along with the formation of silver nanoparticles (AgNPs), a thin layer of compact SiO₂ caps is formed on AgNPs, protecting the silver from aggregation effectively and guaranteeing the stability of the SERS substrates. Their shelf life can be improved greatly. The thin SiO₂ layer, which protects the silver from degradation, can be easily and quickly removed just prior to analysis of optimal SERS performance. This work introduces a creative technique to produce highly stable and efficient 3D-SERS substrates for trace detection of chemical and biological molecules.