Resonant nuclear reaction analysis study of carbon phase formation during carbon ion-implantation into silver substrates

High fluence (1016 to 3 ' 1017 ions cm-2) carbon (13C+ or 12C+) ion-implantations were performed into silver substrates held at high temperature (400'700 °C) to produce carbon onions. The carbon concentration profiles were determined by using the 13C(p,)14N resonant nuclear reaction at the proton energy of 1748 keV. Implanted carbon atoms mainly precipitated inside the bulk of the silver matrix contributing to the formation of carbon onions. Carbon also precipitates onto the surface at the beginning of the implantation process, a phenomenon that concerns at maximum 1% of the implanted carbon atoms. Resonant nuclear reactions analysis characterizations reveal that there is no preferential carbon diffusion towards the surface during the implantation process. Furthermore, sputtering and evaporation of silver are proposed to be the key mechanisms that control the carbon concentration in the near surface region.