Spontaneous formation of single crystal ZnO nanohelices

This paper reports a novel helix-like ZnO nanostructure with several tens of nanometres in thickness synthesized on a gold-coated Si substrate by thermal evaporation of zinc sulfide powder at 1020°C. Transmission electron microscope characterization shows that as-synthesized ZnO nanohelices extend along 01\bar11 direction and the axial direction of the helix is along 0001 direction. A catalyst-intervened dislocation-induced growth mechanism has been suggested to explain the formation of the helix-like ZnO nanostructures. This study opens a new route to construct helix-like ZnO nanostructures by different evaporation sources.