Effect of electric field on Fe2O3 nanowire growth during thermal oxidation

Abstract

A direct current of 5 A was applied to narrow strips of iron foil in air to synthesize iron oxide nanowires (NWs) via thermal oxidation route of resistive heating. Transverse electric fields of 0–4000 V/m were applied perpendicularly to the surface of the iron foil during thermal oxidations. Results showed that the Fe2O3 NW array can grow perpendicularly on that surface by using this kind of thermal oxidation method. Transverse electric fields applied during thermal oxidation significantly affected the morphology of the Fe2O3 NW array. With increasing strength of the transverse electric fields, the Fe2O3 NWs became much longer, thinner and denser in distribution, and the diameters became more uniform. Furthermore, solid state based-up diffusion growth mechanism for the Fe2O3 NW array was confirmed by thermal oxidation.