The Growth of One-Dimensional Oxide Nanostructures by Thermal Oxidation of Metals

The growth of one-dimensional oxide nanostructures by direct oxidation of metals has received extensive attention for its technical simplicity and large growth capabilities. However, the understanding of the basic mechanism leading to the spontaneous oxide whisker formation still remains essentially incomplete. Here we present a review of our systematic studies on the oxide nanowire growth from the oxidation of model metal systems, Cu and Fe. We show that the compressive stresses generated by the volume change associated with the interfacial reaction accompanying the layered oxide growth stimulate oxide nanowire formation and the one-dimensional oxide growth kinetics is controlled by surface diffusion of cations supplied by outward grain boundary diffusion through the oxide layers. We show that the oxide nanowire formation can be effectively promoted by surface bending tensile stress or surface roughening via sandblasting. We further demonstrate that oxygen gas pressure can be employed to manipulate the interfacial reaction, thereby allowing for tuning the oxide growth morphologies via the stress-driven grain boundary diffusion