Fabrication and characterization of eutectic gold–silicon (Au–Si) nanowires

Hypoeutectic, eutectic and hypereutectic gold–silicon (Au–Si) alloys were synthesized using vacuum smelting. When Au and Si were smelted in a vacuum chamber near 1100 °C, Si(g), Si2(g), Si3(g), SiO2(g), Au(g), SiO2(s) and Au2O3(s) were formed rapidly; the quantities of Au and Si lost were estimated from thermodynamic formulas. The nano- and microstructures of the Au–Si eutectic compound were characterized with a SEM and a TEM, which showed a discontinuous phase of Si dispersed and mounted within a matrix phase of Au. Cracks that formed about the Au–Si interface made the Au–Si eutectic brittle. From an Au–Si alloy of superior quality as a bulk material, eutectic nanowires of average diameter 60 nm were fabricated after the alloy was melted and injected into an anodic aluminum-oxide (AAO) template.