Surface-enhanced Raman scattering of silver thin films on as-roughened substrate by reactive ion etching

Abstract

A series of silver films with various degrees of roughness were deposited on smooth and roughened substrates by magnetron sputtering. The effects of substrate roughness on the structure and optical properties of silver thin films were investigated by atomic force microscopy, X-ray diffraction (XRD), optical absorption/scattering, and Raman scattering spectra measurements, respectively. XRD spectra indicate that the substrate roughness has the effects of varying the preferential orientation of silver thin films. Both the plasma edge and interband transition peaks of silver thin films vary due to the variation of surface roughness. Both the optical and Raman scattering intensities are enhanced with the increase in surface roughness due to the surface plasmon resonance. The present fabrication of silver thin film could provide an effective way for SERS substrate.