Field emission properties of bare and gold-coated nickel nanowires grown in polymer ion-track membranes

Abstract

The authors have measured the field emission properties of freestanding bare and Au-coated Ni nanowires randomly distributed on thin metallic substrates. The nanowires of uniform length and diameter were grown in the etched ion-tracked pores of polycarbonate membranes by electrochemical deposition. While bare Ni samples yielded only 1.6×104emitters∕cm2 at 10V∕μm, Au coating of the Ni nanowires improved the emission site density to 1.4×105∕cm2 at 5V∕μm and about 1.6×106emitters∕cm2 at 18V∕μm. Average field enhancement factors β of 331 for bare Ni and 302 for Au-coated Ni nanowires correspond well to their cylindrical shape in the scanning electron microscope images. Stable Fowler-Nordheim-like emission was obtained on average up to currents of about 0.4 and 8μA for bare and Au-coated Ni nanowires, respectively. Locally measured I-V curves, maximum current Imax, and derived β values hint for the clustering of nanowires.