Large-scale preparation of chestnut-like ZnO and Zn-ZnO hollow nanostructures by chemical vapor deposition

Large-scale chestnut-like ZnO and Zn-ZnO hollow nanostructures on Si substrates were prepared without catalyst by a one-step chemical vapor deposition technique. The morphology, composition, and phase structure of as-prepared products were characterized by scanning electron microscopy, energy-dispersive X-ray spectrometry, and X-ray diffraction, respectively. The ZnO consists of chestnut-like nanostructures with hollow interior and a lot of nanoneedles aligning on the surface of the hollow structure in a radial way, whereas the Zn-ZnO shows that long nanowires grew on the chestnut-like hollow structure with a hexagonal flower-like structure on the top layer. A vapor-solid (VS) growth mechanism for the chestnut-like ZnO and Zn-ZnO hollow nanostructures was proposed. The photoluminescence (PL) of ZnO and Zn-ZnO shows a large number of oxygen vacancy defects appeared in the novel hollow nanostructures.