Epitaxial Directional Growth of Tin Oxide (101) Nanowires on Titania (101) Substrate

Highly aligned single crystal SnO2 (101) nanowires were epitaxially grown on TiO2 (101) substrates by thermal evaporation via Au-catalyzed vapor−liquid−solid (VLS) growth. The orientation relationship and interface structure between the nanowires and the substrate were determined by X-ray pole figure and high resolution transmission electron microscopy (HR-TEM) combined with the focused ion beam (FIB) lift-out technique. Epitaxially grown SnO2 (101) nanowires exhibited three angular growth directions ([101], [011], and [01̅1]) with different inclination angles to the substrate due to a tetragonal crystal structure. An atomic stacking model was proposed to describe the angular growth of SnO2 (101) nanowires with ⟨101⟩ growth directions. The obtained results are expected to provide an understanding of the growth direction of nanowires and heteroepitaxial relationships between nanowires and substrate to synthesize the well-aligned SnO2 nanowires, which can be integrated into the electronic devices and lead to enhanced properties in the fields such as Li-ion batteries, dye-sensitized solar cells, and gas sensors.