Ultrathin CuO nanowires grown by thermal oxidation of copper powders in air

Copper powders were thermally treated in the air at a wide temperature range of 200-700 degrees C. It was found that thin CuO nanowires were grown at 300 degrees C and thick CuO nanowires were grown at 500 degrees C. The diameters of the thin CuO nanowires were distributed in the range of 5-10 nm, and the growth directions along [(1) over bar 11] and [110] were observed. In addition, the thermally treated copper powders with ultrathin CuO nanowires showed a broad violet emission band peaking at 402 nm. (C) 2015 Elsevier B.V. All rights reserved.