Precipitation of C, Si and metals nanoparticles in silicon-based gels induced by swift heavy ion irradiation

Studies of irradiation effects in inorganic polymers and gels performed at CSNSM during the last ten years are summarized, and new results concerning the effect of the density of transferred energy on the precipitation kinetics of C, Si and metal clusters are presented. The precipitation yield as a function of the fluence of ions with different masses and energies was investigated by means of various spectroscopies, depending on the particles nature. The rates of gel to ceramics conversion and of C, Si and metal precipitation are determined by the density of electronic excitations and nuclear collisions have little effect. Particles formed by ion irradiation show a narrower size distribution and, consequently, more interesting characteristics for magnetic or optical applications than those formed in heat treated gels.