Effect of post-annealing on the properties of copper oxide thin films obtained from the oxidation of evaporated metallic copper. V. Figueiredo a. , E. Elangovan.
Effect of post-annealing on the properties of copper oxide thin films obtained from the oxidation of evaporated metallic copper V. Figueiredo a, E. Elangovan a,*, G. Gonc¸alves a, P. Barquinha a, L. Pereira a, N. Franco b, E. Alves b, R. Martins a, E. Fortunato a a
Materials Science Department, CENIMAT-I3N and CEMOP-UNINOVA, FCT-UNL, Campus de Caparica, 2829-516 Caparica, Portugal b LFI, Dep. Fı´sica, Instituto Tecnolo´gico e Nuclear, EN10, 2686-953 Sacave´m, Portugal Received 23 October 2007; received in revised form 12 December 2007; accepted 14 December 2007 Available online 23 December 2007
Abstract Thin films of copper oxide were obtained through thermal oxidation (100–450 8C) of evaporated metallic copper (Cu) films on glass substrates. The X-ray diffraction (XRD) studies confirmed the cubic Cu phase of the as-deposited films. The films annealed at 100 8C showed mixed Cu–Cu2O phase, whereas those annealed between 200 and 300 8C showed a single cubic Cu2O phase. A single monoclinic CuO phase was obtained from the films annealed between 350 and 450 8C. The positive sign of the Hall coefficient confirmed the p-type conductivity in the films with Cu2O phase. However, a relatively poor crystallinity of these films limited the p-type characteristics. The films with Cu and CuO phases show n-type conductivity. The surface of the as-deposited is smooth (RMS roughness of 1.47 nm) and comprised of uniformly distributed grains (AFM and SEM analysis). The post-annealing is found to be effective on the distribution of grains and their sizes. The poor transmittance of the as-deposited films (
