Formation of zinc-oxide nanoparticles in SiO2 by ion implantation combined with thermal oxidation

Metal-ion implantation followed by thermal oxidation was carried out to fabricate zinc-oxide (ZnO) nanoparticles (NPs) in silica glass (SiO2). A SiO2 substrate was implanted with Zn+ ions of 60 keV up to 1.0 x 10(17) ions/cm(2). In the as-implanted state, the sample shows a strong absorption peak at similar to 4.8 eV and a weak one at similar to 1.2 eV due to Zn metallic NPs. After annealing in oxygen gas at 700 degrees C for 1 h, the absorption in the visible region disappears and a new absorption edge appears at similar to 3.25 eV. The grazing incidence X-ray diffraction (GXRD) confirms the formation of ZnO NPs. The ZnO NPs show a photoluminescence (PL) peak at 3.32 eV under pulsed nitrogen-laser excitation at 3.68 eV. Annealing at 900 degrees C induces an additional shift of the absorption edge to similar to 5.3 eV. The additional shift indicates the formation of a Zn2SiO4 phase which was confirmed by GXRD. (c) 2005 Elsevier B.V. All rights reserved.