Lateral epitaxial growth of faceted SnO2 nanowires with self-alignment

Abstract

Self-aligned, lateral SnO₂ nanowires (NWs) were grown on r-cut (012) sapphire substrate by thermal evaporation via a Au-catalyzed vapor–liquid–solid (VSL) mechanism. The lateral SnO₂ NWs were hetero-epitaxially grown on r-cut sapphire and the growth direction was [01] of SnO₂, which was confirmed by an X-ray pole figure and high-resolution transmission electron microscopy (HRTEM). The SnO₂ NWs exhibited sawtooth-like morphology in the length direction, and rectangular shape with round corners in the perpendicular direction. The top surface of the SnO₂ NW was (101) and the side surfaces were (020). Consequently, the lateral SnO₂ NWs grew in the direction of a large lattice mismatch with the formation of surface facets and coherent interface in the perpendicular direction. In addition, the effects of gas supply direction and the size of Au catalysts on the growth direction and growth mode of the SnO₂ NWs were examined.