Mechanism and control of sidewall growth and catalyst diffusion on oxide nanowire vapor-liquid-solid growth

Oxide nanowires formed via the vapor-liquid-solid (VLS) mechanism are attractive building blocks toward nanowire-based electronic devices due to their fascinating physical properties. Although well-defined oxide nanowires are strongly required for the applications, tapering during oxide nanowire VLS growth has been detrimental and uncontrollable. Here we demonstrate the mechanism to control the tapering during oxide VLS growth. Suppressing simultaneously both the oxidization of adatoms at the sidewall and the catalyst diffusion from the tip was found to be essential to avoid the tapering. This mechanism would be universal in various oxide nanowire VLS growths.