Fabrication of silver-coated silicon nanowire arrays for surface-enhanced Raman scattering by galvanic displacement processes

Silver-coated silicon nanowire (SiNW) arrays were prepared utilizing galvanic displacement processes consisting of three steps: galvanic displacement deposition of silver particles using a HF-AgNO3 or NH4F-AgNO3 aqueous solution; formation of SiNW arrays by a silver-assisted chemical etching process conducted in the HF-H2O2 aqueous solution; deposition of silver particles on the SiNW arrays from the NH4F-AgNO3 aqueous solution. The effects of the morphology of pre-deposited silver particles and deposition solution on the formation of silver-coated SiNW arrays were discussed. Surface-enhanced Raman scattering (SERS) performances have been studied using Rhodamine 6G (R6G) probe molecules on the silver-coated SiNW substrates.