Fabrication of ZnO ring-like nanostructures at a moderate temperature via a thermal evaporation process

ZnO ring-like nanostructures have been successfully synthesized by thermal evaporation of a mixture of ZnS and active carbon powders at 900 °C. Studies found that as-grown ZnO nanorings grew along the [ 0 1 over(1, ̄) 0 ] direction with the top/bottom surfaces as the (2 over(1, ̄) over(1, ̄) 0) planes, and the (0 0 0 1) polar surface pointing to the center of the rings. The ring-like structures were believed to be formed by bending the (0 0 0 1) polar surface dominated ZnO nanobelts, which was induced by the spontaneous polarization. The synthesis method may be extended to synthesize other semiconducting nanomaterials with similar structures.