Characterization of Ag nanoparticles on Si wafer prepared using Tollen’s reagent and acid-etching

Ag nanoparticles on SiO2/Si surfaces synthesized using the Tollen’s reagent and a subsequent acid-etching were characterized using X-ray photoelectron spectroscopy (XPS). Combining the reduction of the Tollen’s reagent and the chemical etching, one can create naked Ag nanoparticles with various sizes in the size range below 10 nanometers (nm). The reduced particle size by the chemical etching was identified using positive core level shifts with increasing etching time. Ag nanoparticles smaller than 3 nm undergo a reversible oxidation and reduction cycle by reacting with H2O2/H2O and a subsequent heating under vacuum to 150 8C, which was not found for the bulk counterparts and larger particles, demonstrating unique chemical properties of nanoparticles compared to the bulk counterparts