Systematic Study of the Growth of Aligned Arrays of α‐Fe₂O₃ and Fe₃O₄ Nanowires by a Vapor–Solid Process

Growth of aligned and uniform α‐Fe 2 O 3 nanowire (NW) arrays has been achieved by a vapor–solid process. The experimental conditions, such as type of substrate, local growth and geometrical environment, gas‐flow rate, and growth temperature, under which the high density α‐Fe 2 O 3 NW arrays can be grown by a vapor–solid route via the tip‐growth mechanism have been systematically investigated. The density of the α‐Fe 2 O 3 NWs can be enhanced by increasing the concentration of Ni atoms inside the alloy substrate. The synthesized temperature can be as low as 400 °C. Fe 3 O 4 NWs can be produced by converting α‐Fe 2 O 3 NWs in a reducing atmosphere at 450 °C. The transformation of phase and structure have been observed by in situ transmission electron microscopy. The magnetic and field‐emission properties of the NWs indicate their potential applications in nanodevices.