Nano-cluster engineering: A combined ion implantation/co-deposition and ionizing radiation

We have used the energy deposited due to the electronic excitation by post-implantation irradiation to induce the nucleation of nano-clusters of Au in silica. We have produced the Au/silica by two methods. (A) MeV Au implantation into silica, (B) producing thin films of a combined Au and silica on a silica substrate, using co-deposition of gold and silica. The process of ion beam assisted nucleation of nano-clusters was used to reduce the threshold implantation dose, or the Au concentration in the silica host, required to produce Au nano-crystals by at least two orders of magnitude. In this presentation, we applied a similar technique, post-irradiation electronic excitation, to films produced by both ion implantation of Au into silica as well as to films produced using co-deposition of gold and silica. By a co-deposition technique, gold and silica (co-deposited at various concentrations) are grown, then post-irradiated. The resultant Au nano-cluster formation was observed and studied using optical spectroscopy, X-ray diffraction, RBS and TEM.