We employed a simple and effective electroless (EL) plating approach to produce silvernanoparticles (NPs) on bare silicon, on dielectric ZnO nanowires (NWs) and on Si NWs,respectively. The surface stability of the homogeneous Ag NPs formed on the ZnO NWsurfaces was investigated by surface enhanced Raman spectroscopy (SERS), whichshow that the attachment of thiol to the Ag surface can slow down the oxidationprocess, and the SERS signal remains strong for more than ten days. To furtherexamine the Ag NP oxidation process in air, the oxygen content in the siliconnanowire core/Ag sheath composites was monitored by the energy dispersivex-ray (EDX) method. The amount of oxygen in the system increases with time,indicating the silver NPs were continuously oxidized, and it is not clear if saturationis reached in this time period. To investigate the influence of the Ag NPs sizedistribution on the oxidation process, the oxygen amount in the NPs formedby EL deposition and e-beam (EB) evaporation on a bare silicon surface wascompared. Results indicate a faster oxidation process in the EL formed Ag NPs thanthose produced by EB evaporation. We attribute this observation to the smalldiameter of the EL produced silver particles, which results in a higher surface energy.