Hierarchical SnO2 Nanostructures: Linear Assembly of Nanorods on the Nanowire Backbones

Abstract

Single-crystalline SnO2 nanorods were successfully assembled on SnO2 nanowire backbones through a sequential gold-catalyzed thermal evaporation method. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies showed that uniform secondary nanorod branches were epitaxially grown from two side surfaces of the nanowire backbones. These branch rods are parallel to each other with 2-fold symmetry with respect to the backbones. The crystal structure of these as-prepared SnO2 centipede-like nanostructures was identified to coincide to the normal rutile structure. The photoluminescence (PL) properties of single centipede-like SnO2 structures were studied by confocal microscopy, which showed that these structures can act as good optical waveguides. Cathodoluminescence (CL) spectra of the SnO2 branched structures obtained in the SEM−CL system featured a blue emission band around 462 nm that is attributed to a defect-state-related emission.