Regularities of formation of silver/porous silicon nanostructures for Surface Enhanced Raman Scattering

This paper presents results of investigation of formation regularities of nanostructures produced at different modes of immersion deposition onto porous silicon for their use as active substrates in Surface-Enhanced Raman Scattering (SERS). Porous silicon samples were formed by anodization of monocrystalline n+-Si in water-alcohol solution of fluorhydric acid HF. It has been found that the intensity of SERS signal depends significantly on the morphology of nanostructured silver films which in turn depends on the silver salt concentration in the solution for immersion deposition and by the immersion period. Optimal modes of silver depositing have been revealed which made it possible to produce SERS-active substrates allowing reaching the detection limit for copper porphyrin to be 1×10^-11 M of analyte.