Effect of annealing on the conductivity of electroless deposited Ni nanowires and films

We examined the effect of annealing on the conductivity of electroless deposited nickel nanowires and nanofilms. The electroless deposited nanowires were 50-200-nm thick and a few micrometers long. TEM analysis of the wires revealed that they have a bead-like (50 nm in size) structure. On annealing, in a nonoxidizing environment, the beads coalesced to form contiguous wires. Four-point resistance measurements of the nickel nanowires showed that annealed wires have considerably lower resistivity than nonannealed wires. In-situ resistance measurement of Ni nanofilms, during annealing, showed an exponential decay of resistance with temperature. The drop in resistance is thought to be a result of bead coalescence and grain-boundary attrition. After annealing, the resistivity showed a linear dependence on temperature, with the slope indicative of the electron-phonon interaction