Facile vapor-phase synthesis of copper nanostructures on cuprous iodide films

Abstract

One-dimensional growth of copper (Cu) is observed when Cu is deposited on cuprous iodide (CuI) films at elevated temperatures by thermal evaporation in high vacuum. The morphology, crystallinity, and chemical composition were examined for the samples using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. Straight single-crystalline Cu nanowires can be formed on polycrystalline CuI films at 200 °C. Anisotropic growth of Cu in one-dimension was promoted by enhancing grain growth and continuity of CuI films. At a lower temperature of 100 °C, fuzzy branching nanowires were grown on the surface of CuI films, enabling to simply fabricate a self-supporting, highly porous film of Cu. It is revealed that a CuI film serves as a functional substrate to synthesize nanostructured Cu at low temperatures. Possible growth processes are proposed to explain the observed morphology evolution of Cu with respect to synthesis conditions. The characterization of water wettability showed that the hydrophobicity was remarkably enhanced due to the formation of nanostructured Cu on the CuI films.