Structural characterization of Cu metallic clusters in amorphous SiO2 by synchrotron radiation grazing incidence X-ray scattering and diffraction

A structural investigation, based on X-ray methods, has been performed on Cu clusters formed in silica upon Cu ion implantation. Samples were implanted at various doses and annealed to obtain particles of different sizes, Due to the high dilution of the Cu atoms in the samples the intense beams from Synchrotron Radiation sources coupled with area detectors revealed to be necessary for this study. In order to minimize the scattering signal from the substrate the Grazing Incidence geometry was used. The Grazing Incidence Small Angle X-ray Scattering was used to determine the mean gyration radii of the particles and to detect the mutual correlation between the particle positions. Clusters of few nm of diameter were detected randomly distributed in the glass. The Grazing Incidence X-ray Diffraction technique has been used to identify the crystalline phases formed upon the implantation as well as the related lattice parameters. Only the metallic Cu phase has been detected in all the samples with an appreciable lattice parameter contraction for the smaller clusters.