| Two new nanostructures, Plate-shape Nanostructures and Chrysanthemum-shape Nanostructures of SnO2, have been grown on single silicon substrates by Au-Ag alloying catalyst assisted carbothermal evaporation of SnO2 and active carbon powders (thermal CVD). The morphology and structure of the prepared nanostructures are determined on the basis of scanning electron microscopy (SEM), field-emission scanning electron microscopy (FESEM), energy dispersive spectrum (EDS), x-ray diffraction (XRD) and photoluminescence spectra (PL) analysis. The peak at 343 nm is the band-to-band emission peak and the corresponding band gap of SnO2 is calculated by using an accurate full-potential linearized augmented planewave method. The new peak at 416 nm in the measured photoluminescence spectra of SnO2 Plate-shape nanostructures is observed, implying that more luminescence centers exist in SnO2 Plate-shape nanostructures due to nanocrystals and defects. The growth mechanism of SnO2 Plate-shape nanostructures and SnO2 Chrysanthemum-shape nanostructures can be explained on the basis of the vapor-liquid-solid (VLS) processes. |
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