Plasmonics is the most promising field appointed to continue the predictions of the Law of Moore as well as for the
confinement of light on a subwavelength spatial scale, allowing the breaking of the diffraction limit. In that direction, we
have produced by ion implantation, interesting nanocomposites with very attractive optical properties. Recently, a double
implantation of Si and Ag ions in silica, with subsequent thermal treatments in appropriated atmospheres, allowed us to
obtain two layers: one of Si nanocristals (NCs), and other of Ag nanoparticles (NPs). This arrangement shows an
enhancement of the emission of Si nanocrystals (NCs) in a new, totally integrated configuration. The synthesis of the
system by ion implantation offers a total protection of the optical active agents from environmental effects such as
oxidation, additionally assuring a high degree of homogeneity.
We present a photoluminescence excitation study (420-500 nm) of Si NCs, with and without the presence of Ag
nanoparticles (NPs), both embedded in a matrix of SiO2. The level of saturation for Si NCs is independent of the
excitation wavelength, but for Si NCs in the presence of Ag NPs, a saturation level arises for excitation wavelengths near
the absorption band of the surface plasmon resonance of the Ag NP (325-475 nm). The increase of both, the values of
saturation and excitation cross-section of Si NCs in the presence of Ag NPs, is an evidence of the optical interaction
between the metal NPs and Si NCs studied in this work. This suggests a decrease of the lifetime of Si NCs
photoemission due to the interaction with the Ag NPs.