Amorphous silicon-assisted self-catalytic growth of FeSi nanowires in arc plasma

We report the synthesis of FeSi nanowires via a direct current arc discharge method. As material sources, the mixture of Si and Fe powders are put into a graphite crucible that acts as the anode. Free-standing FeSi nanowires are deposited on the iron wires suspended near the cathode without the designed use of any catalyst. The as-grown FeSi nanowires are characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The typical size of the FeSi nanowires is 1–3 μm in length and 10–20 nm in diameter. Based on the traditional vapor-liquid-solid (VLS) growth model, a so-called amorphous silicon-assisted self-catalytic growth process is put forward to explain the growth mechanism of the FeSi nanowires. A photoluminescence emission peak with a maximum at about 600 nm is observed at room temperature. Magnetic characterization is carried out and the results show that the FeSi nanowires exhibit ferromagnetic characteristics at room temperature.