Preparation And Properties Of Ni And NiO Ordered Macroporous Arrays

Nanotechnology has been developed from the synthesis of nanomaterials and their basic qualitative exploration to the unique properties of nanomaterials with different dimensions production application research. In recent years, a new research hotspot of nanomaterials has gradually turned to the two-dimensional orderly nanostructure arrays. The scientists in lorentz Berkeley national laboratory at the university of California point out that the design of nanoscale materials is one of the important frontier subject of modern materials chemistry and physics in a paper just published in Nature. Two-dimensional orderly array structure, is not only one of the leading direction of materials science research, but also has a broad application prospect in in optics, magnetism, information science, catalysis, sensors, optoelectronic devices, photonics, heat, magnetism, data storage and biological technology.Two-dimensional orderly array structure, which refers to choosing corresponding structure unit such as clusters, nanoparticles, nanowire and nano holes according to certain rules of a structural system in the two-dimensional space range, is an important part of nanometer material system. In recent years, the research on the synthesis and properties of nanometer system, more and more cause the attention of people.In this thesis, the construction of large scale and highly ordered nanostructured arrays was fabricated by using colloidal monolayer technique, electrochemical deposition technique, thermal oxidation treatment and magnetron sputtering method, and investigated on their structure-related properties. The dissertation mainly focuses on the design of new synthesis of morphology-controlled nanostructured arrays, structure-related properties. The research results and originates of the dissertation are displayed as follows:1. The construction and magnetic studies of Ni and Ni-Pt alloy orderly holes arrayBy using the polystyrene colloidal crystal as the template, we demonstrate the construction of the elemental Ni on ITO substrate and the Ni-Pt alloy ordered nanostructured arrays on the flexible PET/ITO substrate based on electrochemical deposition technique. The structure, composition and magnetism characteristic of the samples were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM)and energy spectrometer (EDS), vibrating sample magnetometer (VSM), and magnetic force microscope (MFM).The results indicated that the sample of Ni ordered nanostructured arrays are arranged to six party rules, magnetic analysis shows that the samples with small coercive force are good soft magnetic materials, the coercive force and remanence rate change regularly with Angle (external magnetic field and micro-nano array Angle).According to the theoretical analysis, the shape anisotropy of Ni ordered pore array itself is the cause of excellent magnetic properties, mechanism of competition itself magnetocrystalline anisotropy of hole shape anisotropy and the film is caused by the physical nature of the magneticchange. The as prepared Ni-Pt ordered pore array structure is flexible, its six square hole arranged regularly, pore size is about 300 nm, hole spacing of 500 nm, the Pt content in the material is about 1.3%.Magnetic analysis shows that the sample has good soft magnetic materials with small coercive force, in parallel and perpendicular with the direction of the field measured coercivity are respectively 495.77A/m and 770.71 A/m, with the characteristics of magnetic anisotropy.2. Structure and magnetic properties of two and three dimensional ordered macroporous films of nickel oxideUsing polystyrene colloidal crystals as the template, two-dimensional and three-dimensional ordered macroporous NiO thin films were fabricated by the method of electrochemical deposition and thermal oxidation on ITO substrate. The structure, composition and magnetism characteristic of the samples were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) and energy spectrometer (EDS), vibrating sample magnetometer (VSM). The results show that the prepared NiO macroporous film hole diameter and the distance were 500 nm, three-dimensional ordered macroporous NiO films with thickness of 2.4μm.Magnetic analysis shows that the two dimensional and three dimensional ordered macroporous NiO thin films are excellent soft magnetic materials with low coercive force, has the characteristics ofmagnetic anisotropy.3. Study on the electrical properties of NiO-ZnO heterojunctionUsing polystyrene colloidal crystals as templates, we demonstrate P-type NiO thin film by the method of electrochemical deposition and thermal oxidation on ITO substrate, the N-type ZnO thin films was prepared by magnetron sputtering on proper growth conditions on NiO substrates, the NiO-ZnO heterogeneous structure is formed by the P-type NiO ordered porous films and N-type ZnO thin film which grow on the substrate from bottom to top. The morphology and structure were investigated by scanning electron microscope and X ray diffraction, the electrical properties of the heterojunction was measured by electrochemical workstation. The cyclic voltammetry test showed that the NiO-ZnO heterojunction has obvious rectifying characteristics.