  Coral Pt islands films are deposited via electrochemical reduction on silica
coated nanostructured Ag electrodes. From these devices surface enhanced
(resonance) Raman [SE(R)R] signals of molecules exclusively attached to Pt are
obtained with intensities up to 50% of the value determined for Ag. SE(R)R
spectroscopic investigations are carried out with different probe molecules,
silica coating thicknesses and excitation lines. Additionally, field
enhancement calculations on Ag-SiO2-Pt support geometries are performed to
elucidate the influence of the Pt island film nanostructure on the observed
Raman intensities. It is concluded that the non perfect coating of the Pt
island film promotes the efficiency of the induced Pt SER activity. Comparison
with similar measurements on Ag-SiO2-Au electrodes further suggests that the
chemical nature of the deposited metal island film plays a minor role for the
SE(R)R intensity.
