Thermal and electrical transport properties of a single nickel nanowire

Abstract

The thermal conductivity (K), specific heat (C-p) and the resistivity (p) of a single nickel nanowire have been measured in the temperature range from 4 to 300 K by means of the "self heating 3 omega" technique. Starting with a 100 nm nickel film grown on a Si/Si3N4 substrate by thermal evaporation, a suspended nickel nanowire was then fabricated through e-beam lithography and etching processes. The width and length of the wire were determined by scanning electron microscope (SEM) as 180 nm and 35 mu m respectively. At 300 K the thermal conductivity of nanowire is similar to 20% of the bulk, it diminishes to lower value as temperature decreases. The consequence is opposite to that of the bulk and might be explained by the ristriction of mean free paths of electron/phonon-phonon interactions due to the grain boundaries. An enhancement of specific heat similar to 250% of the bulk is also observed. In addition, the resistivity of nanowire at room temperature is about four times larger than that of the bulk. The small relative resistiv-ity ratio (RRR) confirms the polycrystalline characteristic ofthe nanowire.