ZnO- SiO2 nanocomposites were synthesized by ion implanting a Zn+ beam in a silica slide and by annealing in oxidizing atmosphere at 800 °C. A detailed structural and optical characterization was performed by using glancing incidence x-ray diffraction, transmission electron microscopy combined with selected area electron diffraction and energy dispersive spectrometry, optical absorption, and photoluminescence spectroscopies. Samples obtained with three different Zn+ fluences in the range 1-2× 1017 ions/ cm2 have been investigated. According to the results, Zn crystalline nanoparticles were found in the as-implanted Zn- SiO2 samples. The size of the Zn nanoparticles was proportional to the implantation fluence. The annealing in oxidizing atmosphere promotes the total oxidation of the Zn nanoparticles with a preferential migration of the nanoparticles toward the surface of the sample along with an opposite and less pronounced diffusion toward the bulk of the matrix. A relatively strong excitonic peak from the ZnO nanoparticles was observed both in the optical absorption and photoluminescence spectra. We found that the oxidation of the Zn nanoparticles is size-dependent because the time necessary for the total oxidation of the nanoparticles increases with the decreasing in the size of the nanoparticles. This size-oxidation correlation has been explained in terms of arguments related to the stress of the Zn nanoparticles. © 2008 American Institute of Physics.

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