Field emission from ZnO nanostructures with different morphologies

ZnO nanostructures including nanowires, nanocones and microspheres were controllably synthesized by a thermal evaporation method. The morphologies and crystal structures of as-grown samples were characterized by scanning electron microscopy and by X-ray diffraction. The formation of different ZnO nanostructures was dependent on the growth temperature and growth duration. The measurement results of the field emission properties of ZnO nanostructures showed that different morphologies of ZnO nanostructures had a significant effect on their field emission properties; ZnO nanowires exhibited the best electron field emission ability among the three kinds of nanostructures, and this was attributed to a high field-enhancement factor and dense emission sites. (c) 2009 Elsevier B.V. All rights reserved.