Evolutional Transformation of Copper Oxide Nanowires to Copper Nanowires by a Reduction Technique

We report here a simple method to produce copper nanowires on a substrate as an alternative to template approaches and chemical synthesis routes. First, copper oxide nanowires are grown from conventional bulk copper wires by thermal oxidation. The resulting nanowires, which are a mixture of CuO and Cu₂O, are normal to the substrate. Next, these oxide nanowires are reduced to copper nanowires in the same furnace under a hydrogen flow at 400 °C. The evolution of oxide nanowires and their transformation to copper nanowires is studied as a function of time. Electrical characterization reveals a reduction of resistance by six orders of magnitude at the completion of the reduction process.