AG-CD AND CD-AG IMPLANTATIONS INTO HIGH-PURITY SILICA

Silica composites containing nanometer dimension colloids were fabrica ted by implantation of Ag ions followed by Cd ions, and by implantatio n of Cd ions followed by Ag ions. These samples were characterized usi ng transmission electron microscopy and optical spectroscopy. Doses us ed for the sequential implantations were 6 x 10(16) ions/cm(2) of Ag a nd Cd in a 1 to 1 ratio. Single element colloids were also fabricated by implantation of Ag or Cd using the same nominal dose and implantati on energy as the sequential implantations. Sequential implantation of Ag and Cd leads to the formation of multi-component metal nanoclusters and elemental nanoclusters. Different microstructures were obtained d epending on the order of implantation. Optical responses are consisten t with results expected from effective medium theory. (C) 1998 Elsevie r Science B.V.