Phase transformation in FeSi2 nanowires

We report the formation of β-FeSi2 nanowires (NWs) on Si(1 1 0), produced by annealing s-FeSi2 NWs at 800 °C. These two phases of iron silicide are semiconducting and metallic, respectively, in thin film form. The s-phase NWs are formed by reactive deposition at 700 °C and have average dimensions of 5 nm thick×8 nm wide×3 μm long. Both are endotaxial, meaning they grow into the substrate along inclined Si{1 1 1} planes. The transformation temperature is higher than observed in thin films, due to the small thickness and large interface area of the NWs, which stabilize the s-phase.