Formation of metallic nanophases in insulators by high-energy ion-beam mixing

Composite materials consisting of nanometer-sized metallic clusters embedded in a dielectric matrix exhibit interesting optical properties with potential applications to non-linear optics and optoelectronics. Ion implantation appears to be a very promising technique to generate such clusters, but it suffers redhibitory limitations mostly owing to the thickness and homogeneity of the doped material. This paper presents a new methodology, also based on ion-beam processing, used to overcome these drawbacks: high-energy ion-beam mixing, Alternated metallic and insulator multilayers are irradiated with MeV heavy ions at room temperature. The amount of mixing and the homogeneity of the mixed layer are determined by RES experiments performed in situ during the mixing process. The formation of metallic nanoclusters is characterized by X-ray, electron microscopy and optical absorption experiments.