The synthesis of Sn-doped ZnO nanowires on ITO substrate and their optical properties

Single crystalline Sn-doped ZnO nanowires were successfully synthesized on indium tin oxide (ITO)-coated glass substrate by simple thermal evaporation approach without introducing any catalysts. The morphology and microstructure were determined by field emission scanning electron microscopy (FE-SEM), X-ray diffraction, high-resolution transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS) and photoluminescence (PL) spectroscopy. The investigation confirmed that the products were of the wurtzite structure of ZnO. These doped nanowires have diameters in the range 30-50 nm and lengths of several tens of micrometers with growth direction along the c-axis of the crystal plane. Photoluminescence of these doped nanowires exhibits a weak ultraviolet (UV) emission peak at around 400 nm and the strong green emission peak at around 495 nm at room temperature, which may be induced by the Sn-doping. The growth mechanism of the doped nanowires was also discussed.