Field emission characteristics of electrochemically synthesized nickel nanowires with oxygen plasma post-treatment

The field emissive, electrical, magnetic, and structural characteristics of nickel (Ni) nanowires synthesized using the electrochemical deposition method with an alumina nanoporous template are reported. The synthesis and formation of Ni nanowires were confirmed by XRD, SEM, and HR-TEM experiments. Ferromagnetic hysteresis curves and the metallic temperature dependence of the current-voltage characteristics were observed for the Ni nanowire systems. The nanotip emitters of the field emission cells of the Ni nanowires after O₂ plasma treatment were easily patterned using the solution drop casting (SDC) method, in which the Ni nanowires were homogeneously dispersed in organic solvents, and then dropped and dried on an n-type doped Si substrate as the cathode. For the O₂ plasma treated Ni nanowires, we observed that the inhomogeneous oxidized layer on their surface was reduced, that the current density of the field emission cell increased from ∼3.0 × 10^-9 to ∼1.0 × 10^-3 A cm^-2 due to field emission, and that the lowest threshold electric field was ∼4 V νm^-1. The field enhancement factor was estimated as ∼1300 for the O₂ plasma treated Ni nanowires. The evolution of the field emission obtained from the phosphor screen was observed at different applied electric fields.