ZnO nanowire arrays grown on Al: ZnO buffer layers and their enhanced electron field emission

Arrays of highly ordered ZnO nanowires have been synthesized on polycrystalline Al-doped ZnO (AZO) buffer layers prepared on p -Si substrates (7-13cm) with assistance of a thermal deposition method. The diameter and interspacing of the nanowires have been controlled by the growth conditions and properties of AZO films. The optimized array of ZnO nanowires shows low turn-on and threshold fields (∼1.1 and ∼3.0 V/μm, respectively) and displays exceptional time stability of electron field emission. The time-fluctuation instability was found to be less than 0.6% at a current density of 10 mA/ cm2, as measured for 500 min. The low turn-on and threshold fields as well as the stable electron emission current suggest that the arrays of ZnO nanowires could be considered in some electron field emission applications. © 2009 American Institute of Physics.