Chemical and Physical Routes for Composite Materials Synthesis: Ag and Ag2S Nanoparticles in Silica Glass by Sol-Gel and Ion Implantation Techniques

Two composite systems, "Ag" and "Ag-S" nanoparticles in silica films, were approached by using two different synthesis routes, namely sol-gel and ion implantation. Silica composites containing embedded nanosized silver- and silver sulfide-crystallites were obtained by the sol-gel process. The formation of silver nanograins was also observed in Ag-implanted silica samples, while sequential implantation (first Ag then S) led to the formation of core-shell Ag-Ag2S nanoclusters. The systems were then characterised using different analytical tools, i.e. X-ray photoelectron spectroscopy (XPS), X-ray-excited Auger electron spectroscopy (XE-AES), X-ray diffraction (XRD), secondary-ion mass spectrometry (SIMS), Rutherford backscattering spectrometry (RBS) and transmission electron microscopy (TEM). These advanced microscopic and X-ray analytical methods were combined to gain complementary information concerning the composition and microstructure of the investigated composite systems. In addition, the characterisation of both systems by means of several investigation techniques provided a valuable insight into the potential features offered by sol-gel and ion implantation and enabled a fruitful comparison between these preparative routes. The influence of the different synthesis parameters on the final features of the composites is analysed and discussed.