Field Emission From Hydrothermally Grown ZnO Nanoinjectors

An injector-like nanostructure of ZnO fabricated by hydrothermal method was tested for field emission (FE) properties. The turn-on field of 3.8 V/mum was obtained at a current density of 0.1 muA/cm
²
. Above the turn-on field, the emission current density quickly raised up to 1 mA/cm
²
at about 12.8 V/mum. The field enhancement factor beta was estimated to be 2556 and 1226 in the low and high field regions, respectively. The two-slope FE behavior was attributed to the adsorbates and defects which were introduced in the fabrication process in aqueous solution at low temperature. The good FE properties of the ZnO nanoinjectors indicate that they are applicable as low-cost and low-temperature cathode materials for FE-based devices.