Synthesis and characterization of large-scale single-crystal ZnO nanotubes

We demonstrate bulk fabrication of high-quality crystalline ZnO nanotubes by heating Zn nanopowders at 800degreesC which are characterized by Xray diffraction, transmission electron microscopy, energy dispersive X-ray spectroscopy, and selected area electron diffraction. The as-synthesized ZnO nanotubes have the inner diameter of about 20 nm wall thickness of about 6 nm and length up to one micrometer. In particular, the mechanism of growth of the nanotube. is suggested for a novel process in which formation of ZnO nanotubes is due to a quasi-template confinement effect.