Enhancement of field emission in nanotip-decorated ZnO nanobottles

We report a simple fabrication process for the growth of nanotip-decorated ZnO nanobottles with an enhanced field emission property. Well-aligned ZnO nanobottles grown on ITO-coated glass substrates were synthesized by the thermal evaporation technique with the up-side down arrangement of substrate compared with the common method. The hydrothermal growth was carried out to decorate the nanobottles with ZnO nanotips. We demonstrate that the nanobottles decorated with nanotips show a much better field emission property. The improved field emission is attributed to the different local field enhancement factors at the nanobottles tops. Our results confirm the importance of the top morphology of a material in field emission.