Silica nanowire-Au nanoparticle pea-podded composites: Synthesis and structural analyses

Nanoscale wires of silicon oxide, among which some with embedded gold nanoparticles, are synthesized by a standard procedure involving the heating of a gold-coated silicon wafer at temperature higher than 1273 K. We report quantitative and systematic structural analyses of the silicon oxide nanowires with embedded gold nanoparticles performed by scanning electron microscopy, transmission electron microscopy, energy filtered transmission electron microscopy, X-ray diffraction, and optical transmittance measurements. For such pea-podded structures, the analyses allow us to correlate the diameter of the nanoparticles with the diameter of the nanowire in which they are embedded, and the diameter of the nanoparticles with their spacing. The results help in understanding the mechanism inducing the formation of such structures and indicate the coexistence of transport and instability processes during the growth stage.