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.