The Effect of Size and Size Distribution on the Oxidation Kinetics and Plasmonics of Nanoscale Ag Particles
NAVAL RESEARCH LAB WASHINGTON DC ELECTRONICS SCIENCE AND TECHNOLOGY DIV
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We employed a simple and effective electroless EL plating approach to produce silver nanoparticles 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 NW surfaces was investigated by surface enhanced Raman spectroscopy SERS, which show that the attachment of thiol to the Ag surface can slow down the oxidation process, and the SERS signal remains strong for more than ten days. To further examine the Ag NP oxidation process in air, the oxygen content in the silicon nanowire coreAg sheath composites was monitored by the energy dispersive x-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 saturation is reached in this time period. To investigate the influence of the Ag NPs size distribution on the oxidation process, the oxygen amount in the NPs formed by EL deposition and e-beam EB evaporation on a bare silicon surface was compared. Results indicate a faster oxidation process in the EL formed Ag NPs than those produced by EB evaporation. We attribute this observation to the small diameter of the EL produced silver particles, which results in a higher surface energy.
- Physical Chemistry
- Coatings, Colorants and Finishes
- Metallurgy and Metallography