Composite materials formed by metal nanoclusters (NCs) embedded in dielectric films (Metal Nanocluster Composite Film, MNCF) are the object of several studies owing to their peculiar properties suitable for application in several fields, such as nonlinear optics, photoluminescence, catalysis, or magnetism [1-4]. Recently, also sensitizing effects for rare earth ions luminescence have been reported as due to energy transfer between metallic NCs and Er ions in silica glass [5]. Updated review chapter dealing with MNCFs are currently published, each one covering one or more particular

aspects, ranging from preparation techniques to properties and characterization. In particular, by ion implantation, very large doping concentration values can be obtained in the ion irradiated region, with a modification of chemical and physical material properties. A proper choice of implantation energies and fluences allows to predetermining the composition, the depth and the spatial shape of the modified layer. A fundamental feature of ion implantation is that the implantation process does not take place under thermodynamic equilibrium and consequently the usual solubility limits of the implanted ions in the host can be largely overcome, achieving impurity local concentrations inaccessible by conventional synthesis routes.