Stable field emission performance from urchin-like ZnO nanostructures

Abstract

The field emission properties of ZnO are often strongly affected by their morphology andstructure. The field emission properties of the 3D urchin-like ZnO nanostructures,which consisted of ZnO nanorods with sharp tips and were self-assembled via asimple hydrothermal route, are investigated in detail. The urchin-like ZnOnanostructures show a good field emission performance with a turn-on field of∼3.7 V µm−1 (at10 µA cm−2) and a thresholdfield of ∼4.8 V µm−1 (at1 mA cm−2) and goodstability (<4%, during a 250 min test). The field enhancement factorβ is estimated to be 1239. The field emission performance from the present ZnOforms can be comparable to the best value of ZnO nanostructures reported in theliterature. It is demonstrated that the ZnO nanorod sharp tip morphology results in agood and stable field emission performance, which may find applications in fieldemitters.