Hybrid nanostructured supports for Surface Enhanced Raman Scattering

Porous silicon solid supports with pore diameter 0.5-1 microns, infiltrated with Ag nanostructures for Surface Enhanced Raman Scattering, were prepared according to two procedures: spontaneous Ag+ reduction on the surface of freshly etched porous silicon immersed in Ag+ aqueous solutions , or anchoring colloidal Ag nanoparticles on the surface previously functionalized by aminosilane. Using rodhamine-6G as analyte the detection limits were of the order of 20 micro-M and 20 nano-M with porous silicon metalized by the first and second procedure, respectively. This large increase of sensitivity notwithstanding a reduced surface density of rodhamine-6G obtained on porous silicon metalized by the second procedure is discussed in terms of better hot spot efficiency and reduced aspecific binding out of the hot regions obtained depositing the colloids on the aminosilane functionalized surface