Formation and optical characterization of multi-component Ag-Sb nanometer dimension colloids formed by sequential ion implantation in silica

The optical properties of nanometer dimension metal colloids formed by the sequential implantation of Ag then Sb in silica are characterized as a function of the relative concentrations of Ag and Sb implanted. The doses used were in ratios, Ag to Sb, of 9:3, 6:6 and 3:9. Energy of implantation was 305 keV for the Ag and 320 keV for the Sb. Nominal total doses as determined by current integration for the three samples were 12 X 10(16) (Ag + Sb) ions/cm(2). Single element colloids were also made by implantation using the same nominal doses as the sequentially implanted samples. Sequential implantation of Ag and Sb leads to the formation of multi-component metal nanoclusters. Changes in the composition of the colloids from sequential implantation result in significantly different optical responses for these samples compared to the single element implanted samples. The optical responses are consistent with results expected from effective medium theory.