Single-crystal nanocastles of ZnO

As a result of switching the growth from hexagonal disks to nanorods/nanobelts, single-crystalline ‘nanocastles’ of ZnO have been synthesized. This new structure was constructed by two basic parts: a sheet-like hexagonal crystal base and vertical nanorods/nanobelts surrounding the base as the ‘walls’ of the castle. Moreover, for the first time, ZnO nanorods with a triangular and diamond cross-sections were found growing on top of the nanocastles. The whole nanocastle structure was enclosed by the (0 0 0 1) and {01 1 ¯ 0} facets. This configuration is a new member in the family of ZnO nanostructures. The in situ morphology switching mechanism would be an useful technique for fabricating high quality heterostructures or interconnects at nanometer scale.