Synthesis and characterization of ZnO nanowires using electrodeposition and thermal oxidation and their application as field emitter

ZnO nanocrystalline thin films were synthesized using cathodic reduction of Zn foil in aqueous electrolyte containing ZnCl2 and H2O2، followed by annealing at 400 oC in the air. The X-ray diffraction pattern exhibited a set of well-defined diffraction peaks corresponding to the ZnO wurtzite phase. Scanning electron microscope and transmission electron microscope images clearly revealed formation of randomly oriented ZnO nanowires having length up to several microns and diameter of ~ 100 nm. The field an emission studies were carried out in a planar diode configuration at a base pressure ~ 1x10-8 mbar. The turn-on field value، required to draw emission current density of 0. 1 mA/cm2 was found to be ~ 1. 2 V/mm. The Folwer-Nordheim (F-N) plot showed non-linear behavior in the entire range of applied field indicating the semiconducting nature of the emitter. The simplicity of the synthesis route، coupled with the better emission properties، proposes the electrochemically synthesized ZnO nanowire emitter as a promising electron source for high current density applications.