Correlation between formation of layered nanoparticles in phase separated films and ion beam assisted deposition

Au nanoparticles embedded in silica were prepared using electron beam evaporation of gold and silica together with 50 eV Ar+ bombardment followed by post-deposition annealing. Thin films were characterized using X-ray diffraction, X-ray reflectivity, TEM, and optical spectra. The Au nanoparticles have an average diameter around 12 nm and a preferred (200) orientation. Spatially, they are distributed into a multilayered structure. The formation of layered nanoparticles is proposed to correlate to the phase separation guided by experimentally observed pre-existing compositional modulations in the as-deposited Au–silica film.