Silicon nanocrystals and defects produced by silicon and silicon-and-gold implantation in silica

High-purity silica samples were implanted at room temperature with 2-MeV Si ions or sequentially with 2-MeV Si and 10-MeV Au ions. Three photoluminescence bands associated with the presence of defects are identified in the as-implanted samples. After a heat treatment at 1100 °C, a line appears at 750 nm in Si-implanted samples. This line is attributed to the emission from localized states in Si nanocrystals. At this temperature, the defects are only partially annealed. In the case of the samples implanted sequentially with Si and Au ions, the Si nanocrystal emission band appears, even without heat treatment.