Optical and magnetic properties of CuO nanowires grown by thermal oxidation

CuO nanostructures with different morphologies, such as single-crystal nanowires, nanoribbons and nanorods, have been grown by thermal oxidation of copper in the 380–900 °C temperature range. Cathodoluminescence spectra of the nanostructures show a band peaked at 1.31 eV which is associated with near band gap transitions of CuO. Two additional bands centred at about 1.23 and 1.11 eV, suggested to be due to defects, are observed for nanostructures grown at high temperatures. The magnetic behaviour of nanowires with lengths in the range of several micrometres and diameters of 50–120 nm has been investigated. Hysteresis loops of the nanowires show ferromagnetic behaviour from 5 K to room temperature