Growth mechanism and photoluminescence of the SnO2 nanotwists on thin film and the SnO2 short nanowires on nanorods

SnO₂ nanotwists on thin film and SnO₂ short nanowires onnanorods have been grown on single silicon substrates by usingAu--Ag alloying catalyst assisted carbothermal evaporation ofSnO₂ and active carbon powders. The morphology and thestructure of the prepared nanostructures are determined on the basisof field-emission scanning electron microscopy (FESEM), transmissionelectron microscopy (TEM), selected area electronic diffraction(SAED), high-resolution transmission electron microscopy (HRTEM),x-ray diffraction (XRD), Raman and photoluminescence (PL) spectraanalysis. The new peaks at 356, 450, and 489 nm in the measured PLspectra of two kinds of SnO₂ nanostructures are observed,implying that more luminescence centres exist in these SnO₂nanostructures due to nanocrystals and defects. The growth mechanismof these nanostructures belongs to the vapour--liquid--solid (VLS)mechanism.