SERS-active Ag/Au bimetallic nanoalloys on Si/SiOx

Nanoalloys are clusters formed of two or more metallic elements and are of interest for applications in catalysis, spectroscopy, photonics, electronics, and magnetism. The hybridization of the individual plasmonic absorptions of different alloyed metals allows for plasmon tunability and a better coupling of plasmon-excitation line, giving rise to significant increases in the enhancement factor for surface-enhanced Raman scattering (SERS) spectroscopy. Here we report simple fabrication procedures for the preparation of Ag/Au nanoalloys on Si/SiO(x) substrates, with tunable plasmon resonances. The mechanism and kinetic of the nanoalloy formation and its optical properties were studied by SEM, XPS, SPR, and SERS.