Controllable template synthesis of superconducting Zn nanowires with different microstructures by electrochemical deposition.

A systematic study was conducted on the fabrication, structural characterization, and transport properties of Zn nanowires with diameters between 40 and 100 nm. Zinc nanowires were fabricated by electrodepositing Zn into commercially available polycarbonate (PC) or anodic aluminum oxide (AAO) membranes. By controlling the electrodeposition process, we found that the nanowires can be single-crystal, polycrystalline Zn, crystalline Zn/nanocrystalline ZnO composites, or entirely ZnO. The microstructure and chemistry was characterized by using transmission electron microscopy. Transport studies on single-crystal or polycrystalline Zn nanowire arrays embedded inside the membrane showed that the superconducting transition temperature, Tc, is insensitive to the nanowire diameter and morphology. The superconductivity shows a clear crossover from bulklike to quasi-1D behavior, as evidenced by residual low-temperature resistance, when the diameter of the wires is reduced to 70 nm (20 times smaller than the bulk coherence length).