Self-Assembled Highly Faceted Wurtzite-Type ZnS Single-Crystalline Nanotubes with Hexagonal Cross-Sections

摘要

Highly hexagonal-faceted ZnS nanotubes have been self-assembled via a thermochemistry process. Typically, the synthesized ZnS nanotubes have a length of several to tens of micrometers, and have diameters of 120-150 nm and wall thicknesses of 8-10 nm. For the formation process of the highly hexagonal-faceted tubular ZnS, no templates or metal catalysts were utilized. The typical crystal habit exhibits a basal polar sulfur plane (0001) and a top tetrahedron corner-exposed polar zinc (0001) face. The faceted ZnS nanotubes grow along the < 0001 >direction, and are closed by low-index faces consisting of non-polar {1000} faces. It was shown that the synthesis temperature and reactor gas pressure play an important role in the formation of ZnS nanotubes. The synthesized ZnS tubes exhibit a weak blue emission centered at 439 nm and a strong green emission centered at about 538 nm. The emission bands from the faceted tubes may be derived from the large surface-to-volume ratio in the synthesized faceted nanotubes, and the stoichiometric defects including self-activated centers, vacancy states, and interstitial states related to the peculiar nanostructures.