Surface enhanced Raman scattering (SERS) substrate and preparation method thereof

The invention provides a surface enhanced Raman scattering (SERS) substrate and a preparation method thereof. The SERS substrate comprises a silicon substrate and a chemical modification layer arranged on the silicon substrate. The chemical modification layer includes a hydrophilic silane compound layer with area smaller than 7.5 square millimeter; a hydrophobic silane compound layer surrounding the hydrophilic silane compound layer; and a mono-layer metal nanoparticle layer arranged on the hydrophilic silane compound layer. Under action of the hydrophilic silane compound layer and the hydrophobic silane compound layer, aqueous solution of to-be-detected substance is concentrated on the middle small-area hydrophilic silane compound layer, to improve concentration degree of aqueous solution of the to-be-detected substance. The metal nanoparticle layer realizes more uniform distribution of aqueous solution of the to-be-detected substance. Therefore, the SERS substrate can improve signal intensity and detection sensitivity.