Study On Preparation And Optical Properties Of Metallic Oxide Nanostructures

Zinc oxide (ZnO) is an important wide band gap n-type semiconductor material,copper oxide (CuO) is an important narrow band gap p-type semiconductor material.Both of them are widely used in photocatalysis, solar cells, field emission devices,sensor and so on. In this paper, Multiform ZnO nanostructures were synthesized byelectrochemical deposition method and thermal evaporation method, CuO nanoflowersand CuO nanowires with Cu2O quantum dots nanostructure were prepared byelectrochemical deposition method. The obtained products were characterized by X-raydiffraction (XRD), field emission scanning electron microscopy (FESEM), transmissionelectron microscopy (TEM), energy disperse spectroscopy(EDS), ultraviolet visibleabsorption (UV-vis)，Raman scattering and photoluminescence (PL) spectroscopy toobtain the structural and optical properties. The main contents are as follows:1. Multiform ZnO nanostructures array controlled synthesis and optical propertiesMultiform ZnO nanostructures, such as nanotubes, nanorods with tower-like tips,cone-like tips and groove-like tips, are controllably synthesized by electrochemicaldeposition method at60oC, which is lower compared with the prepared temperatures ofreported works. The results of XRD indicate the wurtzite ZnO nanostructures aresingle-crystalline and grow along the c-axis perpendicularly on the substrate. The bandgap of ZnO nanostructures changes from2.57to3.39eV in UV-vis absorption test.Multiform ZnO nanostructures array are promising candidates for future applications inoptoelectronic nanodevices and field emission devices.2. Preparation, microstructure and spectroscopy of ZnO nanobrushsTwo different ZnO nanobrushs were first synthesized by thermal evaporation method.The products were characterized in detail by XRD, FESEM and TEM, showed thenanobrushs trunk growth along [0001] direction. The band-like bristles growth alongthe[1100],[1010] and [0110](or [1100],[0110] and [1010]) three equivalent direction;the needle-like bristles growth along the [1100],[0110],[1010],[1100],[0110] and [1010] six equivalent direction. The test for ZnO nanobrushs bandgap of UV-visabsorption spectrum is3.15eV and3.21eV, because of the ZnO nanostructures smallsize effect and the quantum size effect. Photoluminescence spectrum obversed that a wide and high strength defect luminous zone because of oxygen vacancy, zincdeficiency or the distribution of ZnO structures.3. Preparation and spectroscopy of CuO nanoflowers and CuO nanowires withCu2O quantum dotsCuO nanoflowers and CuO nanowires with Cu2O quantum dots nanostructures weresynthesized by a template-free electrochemical deposition method. The results of XRDindicate the the monoclinic phase CuO nanostructures and cubic phase Cu2Onanostructures. The PL spectra of CuO nanoflowers and CuO nanowires with Cu2Oquantum dots structures indicated that CuO nanowires with Cu2O quantum dotsstructure less defects than CuO nanoflowers. The Raman spectra of CuO nanoflowersshow Cu2O characteristic peak are not found, we analyse that the product is pure CuO;the Raman spectra of CuO nanowires with Cu2O quantum dot structure show twocharacteristic peaks of Cu2O, we analyse the surface of CuO nanowires with Cu2Oquantum dots structure is mainly Cu2O quantum dots.