Influence of mesoporous silicon preparation condition on silver clustering and SERS enhancement

Mesoporous Si samples, prepared by anodisation technique with different current densities (0.5–40 mA/cm2), were silver coated by using immersion plating into 10–2 and 10–3 m AgNO3 solutions. It was shown that different porous structures yield formation of different Ag crystals on the surface of mesoporous Si for the same immersion conditions. The effect of immersion time on the morphology of Ag crystals and the corresponding surface-enhanced Raman spectroscopy (SERS) activity were monitored by using the rhodamine 6G dye molecule. A strong difference in the enhancement factor of the SERS signal in the silver-clustered mesoporous silicon in comparison with that in crystalline silicon was found. It was shown that respectable enhancement of the SERS substrates with detection limits of 10−9 m rhodamine 6G is possible to produce by optimisation of anodisation current, concentration of AgNO3 and silver crystals’ growth time. Copyright © 2016 John Wiley & Sons, Ltd.