Tunable Ordered Silver Nano-Arrays Prepared by TiO₂ Templates as Surface-Enhanced Raman Scattering Substrates

Surface-enhanced Raman spectroscopy has attracted much attention because it is a sensitive non-destructive technique offering the possibility of quantitative analysis down to the molecular level. Much research has hitherto been dedicated to the fabrication of substrates with high enhancement effects based on the electromagnetic or chemical mechanism. In this work, surfaced-enhanced Raman scattering is performed to probe rhodamine 6 g on highly-ordered multi-scale silver nano-arrays prepared by magnetron sputtering using templates with close end tubes of titania (TiO₂) membranes. The surface morphology can be controlled by adjusting the anodization voltage and thickness of the silver film. This simple and flexible technique produces substrates with high enhancement factors stemming from controlled optimization of the hot spots. The electromagnetic field distribution is analyzed by finite difference time domain simulation and the theoretical and experimental results are in good agreement revealing the potential of rapid surfaced-enhanced Raman scattering detection. This low-cost and rapid technique can be readily scaled up for mass production.