SERS-active Ag nanoparticles embedded in glass prepared by a two-step electric field-assisted diffusion

A highly stable substrate used for surface-enhanced Raman scattering (SERS) was fabricated by combining two-step electric field-assisted diffusion (EFAD) with subsequent annealing. The samples were characterized by UV/Vis spectroscopy, X-ray diffraction analysis (XRD), X-ray photoelectron spectra (XPS), atomic force microscopy (AFM) and transmission electron microscopy (TEM). The SERS activity of these substrates was evaluated by using Rhodamine 6G (R6G) as the probe molecule. The results showed that the Raman signals were significantly enhanced in our substrates. The reverse EFAD process was applied to induce larger silver NPs or aggregates formed in the glass, leading to a stronger SERS signal. The enhancement factor about 10 6 and the detection limit of 10 −9   M for R6G were achieved. This method is also very simple and cost-effective and provides a novel pathway for the development of future SERS sensor chips.