Single-Crystalline Pb Nanowires Grown by Galvanic Displacement Reactions of Pb Ions on Zinc Foils and Their Superconducting Properties

Abstract

Single-crystalline Pb nanowires (NWs) have been grown with galvanic displacement method on the zinc foil using Zn as a reducing agent at room temperature. The Pb NWs are hundreds of micrometers long with an average diameter of 80 nm. Heterostructured metal/semiconductor Pb/ZnOx core−shell nanocables were byproducts of the reactions. ZnOx shells served as a protective layer but can be stripped readily with a dilute HCl etching. The inner Pb cores were melted and leaked out and polycrystalline ZnO nanotubes were obtained after annealing at 400 °C. The superconducting transition temperature was measured to be about 7 K. The cathodoluminescence of ZnO nanotubes presents two emission bands around 380 and 590 nm. The work represents for the first time the achievement to produce the metallic NWs with the efficient and low-cost galvanic displacement method.