Direct synthesis of vertical α-Fe2O3 nanowires from sputtered Fe thin film

Abstract

α -Fe 2 O 3 (hematite) nanowires were synthesized from Fe thin films. The bladelike nanowires were synthesized by the simple annealing of a sputtered Fe thin film in a furnace with the annealing time varied between 0 and 100 min. The length of the nanowires was proportional to the logarithm of the annealing time. The number density of nanowires was saturated within an annealing time of 0–1 min. The Fe thin film may have been oxidized during annealing and the iron oxide molecules may have diffused to the roots of nanowires in accordance with the solid-phase growth model or they may have vaporized and then have been deposited on the surface of nanowires in accordance with the vapor-liquid-solid model. The authors characterized the nanowires by Raman spectroscopy and transmission electron microscopy (TEM). The Raman shift and the results of TEM indicated that the nanowires consisted of trigonal α-Fe2O3.