Microstructure and photoluminescence properties of bulk-quantity SnO2 nanowires coated with ZnO nanocrystals

Large-quantity single-crystal SnO2 nanowires coated with ZnO nanocrystals (nc-ZnO/SnO2 nanowires) were directly synthesized by a one-step thermal evaporation process. SnO2 nanowires were single-crystalline tetragonal structures with the diameters and lengths of 50-100 nm and several tens of micrometres, respectively. ZnO nanocrystals were single-crystalline wurtzite structures with average diameters less than 5 nm, which coated the whole SnO2 nanowires uniformly. Photoluminescence measurements showed that the nc-ZnO/SnO2 nanowires had a much stronger near-band UV emission (at 393 nm) than pure SnO2 nanowires. The Sn doping into ZnO nanocrystals may be a most possible reason for the redshift and broadening of UV emission peaks from nc-ZnO/SnO2 nanowires. The microstructure and photoluminescence properties of the nc-ZnO/SnO2 nanowires are discussed.