Silica sol-gel materials with metal and semiconductor nanoparticles: synthesis, structure and optical features

Recent achievements on fabrication, structure and optical features of the metal- and semiconductor-doped silica sol-gel materials are reviewed. The nanoparticles of copper and copper compounds (oxides, sulfides and selenides) have been produced by means of the modified silica-based sol-gel technique within the two types of materials: amorphous silica films and monolithic glasses. The features of optical absorption are discussed in dependence on chemical composition. They are variable by stoichiometry of the compounds, size of particles, their concentration and localization in the matrix. These factors determine optical properties of mate- rials and open pathways of their application, in particular, as switching and beam-controlling elements in near-IR lasers. The quantum confinement and a partial surface chemical modification of the nanoparticles are considered as possible reasons for occurrence of the optical features specific for the copper multivalent compounds