Spitzer shaped ZnO nanostructures for enhancement of field electron emission behaviors

We observed enhanced field emission (FE) behavior for spitzer shaped ZnO nanowires synthesized via a hydrothermal approach. The spitzer shaped and pointed tipped 1D ZnO nanowires of average diameter 120 nm and length ∼5-6 μm were randomly grown over an ITO coated glass substrate. The turn-on field (E _on) of 1.56 V μm^-1 required to draw a current density of 10 μA cm^-2 from these spitzer shaped ZnO nanowires is significantly lower than that of pristine and doped ZnO nanostructures, and MoS₂@TiO₂ heterostructure based FE devices. The orthodoxy test that was performed confirms the feasibility of a field enhancement factor (β _FE) of 3924 for ZnO/ITO emitters. The enhancement in FE behavior can be attributed to the spitzer shaped nanotips, sharply pointed nanotips and individual dispersion of the ZnO nanowires. The ZnO/ITO emitters exhibited very stable electron emission with average current fluctuations of ±5%. Our investigations suggest that the spitzer shaped ZnO nanowires have potential for further improving in electron emission and other functionalities after forming tunable nano-hetero-architectures with metal or conducting materials.