Two-Step Synthesis of ZnO Rod-Needle Nanostructures Using a ZnS Source

A novel ZnO rod-needle nanostructure with a gold nanoparticle on the tip has been prepared by combining electrochemical deposition and thermal evaporation methods. The morphologies were characterized by field-emission scanning electron microscopy and transmission electron microscopy. It is found that only a single ZnO nanoneedle is located on the top of each ZnO nanorod. The density and length of this ZnO rod-needle nanostructure can be tuned feasibly. An intriguing phenomenon of crystal lattice rotation between ZnO nanoneedle and nanorod segments is observed and explained in detail. The adoption of ZnS as the source plays an important role in the formation of this structure and the rotation of crystal planes.