Formation of Nanostructures with a Controlled Size Distribution in Si-based Gels by Ion Irradiation

Abstract

Studies of irradiation effects in inorganic polymers and gels performed at CSNSM during the past 10 years are overviewed and examples of precipitations with interesting applications (C, Si, metals) occurring during the conversion into ceramics are presented. The precipitation yield, as a function of irradiation fluence or annealing conditions, and particle physical properties were investigated by means of various techniques, depending on their nature. The rates of gel-to-ceramics conversion and of precipitation are determined by the density of electronic excitations produced by ion irradiation (collision cascades slightly assisting the diffusion of metal atoms). Particles formed by ion irradiation show a narrower range of sizes and consequently more interesting characteristics for magnetic or optical applications than those formed in heat-treated gels