Fabrication of ZnO nanoparticles in SiO2 by ion implantation combined with thermal oxidation

Zinc-oxide (ZnO) nanoparticles (NPs) are fabricated in silica glasses (SiO2) by implantation of Zn+ ions of 60 keV up to 1.0x1017 ions/cm2 and following thermal oxidation. After the oxidation at 700 deg. C for 1 h, the absorption in the visible region due to Zn metallic NPs disappears and a new absorption edge due to ZnO appears at ∼3.25 eV. Cross-sectional transmission electron microscopy confirms the formation of ZnO NPs of 5-10 nm in diameter within the near-surface region of ∼80 nm thick and larger ZnO NPs on the surface. Under He-Cd laser excitation at λ=325 nm, an exciton luminescence peak centered at 375 nm with FWHM of 113 meV was observed at room temperature