Double implantation in silica glass for metal cluster composite formation: a study by synchrotron radiation techniques

Silica glass containing metal clusters is studied for both basic and applied aspects, related to the physics of cluster formation and to the optical properties of these materials. To obtain such composite structure, Cu + Ni, Au + Cu, Au + Ag, Cu + Co, and Cu + Ag sequential implantations in fused silica were realized. The resulting systems, after possible annealing in various atmospheres, were studied by synchrotron radiation-based techniques, namely, extended X-ray absorption fine structure (EXAFS) spectroscopy, grazing incidence X-ray diffraction (GIXRD), and grazing incidence small angle X-ray scattering (GISAXS). The unique potential of these techniques is the capability to investigate dilute (volume fraction of clusters⩾0.01) and very thin (50 nm) systems. In the presented experiment, both pure and alloy clusters in the nanometer range of size were observed to form, pointing out the complexity of the cluster formation process in terms of physical and chemical driving forces.