Electron emission characteristics of Au-covered tungsten〈111〉 nanotips

We have investigated emission properties of Au-covered W〈111〉 nanotips fabricated by means of an electroplating method. The stable nanotips possessed a, three-sided pyramid structure terminated with three atoms, differing from the nanotips covered with the other noble metals such as Pd, Pt, Rh, and Ir, of which all the final structures are terminated with a single atom. The observed values of the Au-covered nanotips were comparable with those of single-atom tips covered with the other noble metals; they were the semi-cone angle of 2 degrees, the brightness of 5 × 10⁸ A/cm ²sr, and the half maximum full-widths of spectra, 0.3 eV. In addition, the self-repairing function and the demountable characteristic have been confirmed. As compared with other metal-covered nanotips, the other different feature of the Au-covered nanotips was their high reproducibility of the energy spectra. The hump always appeared at about 0.7 eV below Fermi level.