Growth evolution of self-catalytic tin-doped indium oxide nanowires

Self-catalytic tin-doped indium oxide nanowires were prepared via thermal-chemical vapor deposition. The growth evolution of these nanowires with respect to the growth time was investigated. Furthermore, the effect of oxygen gas flow on the growth was determined by comparing nanowires grown with/without the flow. In the early growth stages, the nanowires crawled to the substrate after droplet formation. Based on the Ellingham diagram and the difference between the energy barriers, Sn remained in the liquid phase on the head of the nanowires, whereas In2O3 formed as the stem of the wires. After 30 s of growth, the head of the crawling nanowires separated from the substrate, regardless of the droplet size. The droplets were almost completely eliminated from the end of the ITO nanowires grown under the oxygen gas flow but were present at the tips of the wires grown without the flow. The ITO nanowires grown under the flow were characterized by a turn-on field and field enhancement factor of ∼3.4 V/μm and 1632, respectively. The present work provides the mechanism for the growth of nanowires and the design architecture of materials used in various applications.