Investigation of individual CuO nanorods by polarized micro-Raman scattering

Rod-shaped CuO nanostructures were successfully synthesized by a one-step annealing process in air using copper plates as starting material. Phase analysis was carried out using X-ray diffraction, transmission electron microscopy and micro-Raman scattering and the results confirmed the nanorods as single-phase CuO. For the first time, single individual CuO nanorods with different aspect ratios were investigated by polarized micro-Raman scattering in this work. An obvious anisotropy in the intensity of Raman modes was observed when the electric field vector of the incident laser beam is parallel and perpendicular to the long axis of a nanorod. The mechanism responsible for the observed polarized Raman spectra was attributed to the polarization effect produced by the large length to diameter ratio of the nanorods and the large dielectric contrast between these nanorods and their surrounding environment.