Fabrication, structure, and luminescence properties of ZnTiO3/ZnO coaxial nanowires

초록

ZnTiO3/ZnO coaxial nanowires were successfully synthesized on (100) Si substrates by thermal evaporation of a mixture of ZnO and TiO2 powders followed by atomic layer deposition of ZnO. X-ray diffraction, scanning electron microscopy and transmission electron microscopy (TEM) analyses showed that the diameters and lengths of the coaxial nanowires were a few hundreds of nanometers and a few tens of micrometers, respectively, and the ZnO shell layer thickness ranged from 10 to 13 nm. TEM and X-ray diffraction analyses indicated that the cores and shells of the coaxial nanowires comprised a single crystal perovskite-structured ZnTiO3 and a single crystal wurtzite-structured ZnO, respectively. Photoluminescence measurements showed that the ZnTiO3 nanowires had a strong emission band centered at approximately 355 nm in the near-ultraviolet region In contrast, ZnTiO3/ZnO coaxial nanowires had two emission bands: a strong emission band centered at ~370 nm in the near-ultraviolet region and a weak emission band at ~570 nm in the yellow region. The yellow emission might be from the ZnO shells in the ZnTiO3/ZnO coaxial nanowires whereas the weak near-ultraviolet emission might be from the ZnTiO3 cores and ZnO shells in the core-shell nanowires.