| Nano-science and technology is one of the most important contents of the science and technology industrial revolution in 21 centuries. As having the merits of common composite materials and modern nanometer materials , nano-composite thin films have been widely studied. Recent several decades, nano-structure growing on oxides matrix has caused extensive concern and research in the scope of the world. With the variations of size, shape and interaction of the prepared nano-structure, chemical and physical characteristics of the composite materials present a diversification in a very big scope. Electronics structure becomes one of the most important roles to decide the properties of interactions between metal-metal or metal-oxide as the rapid increases of surface ratio and quantum size effect. And thus, it greatly influences the function characteristic of the compound materials.Silicon dioxide will often be chosen to grow some metal nano-stuctures, because it has many excellent characteristics and has huge applications in the semi-conductor production and the electronics industry. Copper dioxide is a semiconducting, antiferromagnetic material with an indirect band gap of 1.0 eV, which has been applied in superconductive material, hot electricity material, transducer, glass, porcelain and ceramics, etc.The copper dioxide / silicon oxide (CuO/SiO2) nano-composite thin films are prepared on n-type Si(111) substrates by radio frequency (RF) magnetron co-sputtering and subsequently high temperature annealing with a Cu/SiO2 composite target. The structure, morphology and photoluminescent properties of the films are determined by X-ray diffraction (XRD), Fourier transform infrared transmission spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Scanning electronic microscopy (SEM) and Photoluminescence (PL). The results show that the as-deposited film is mainly amorphous phase and crystallization takes place in the composite films and a little quantity CuO with small granule sizes is formed after annealed in NH3 at 900℃for 30min. With the further increasing annealing temperature, crystallization quality becomes much better, but it's morphology remais granule thin film. The sample annealed in N2 crystallizes with small sizes granules monoclinic CuO. With the further increasing annealing temperature and a part of monoclinic CuO changes into cubic CuO, which may nucleate into CuO nanoclusters embedded in SiO2 matrix. The CuO one-dimension nanowires are formed annealed in N2 at 1100℃. Excited by 488nm light at room temperature, the films are found strong emission peaks at 431nm. The purple-light emission peak may be ascribed to the electron transition from the defect level,resulting from the Cu vacancies to the conductor band of CuO composite film. The stong emission peaks may be also attribute to the Si-O related luminescence-center of amorphous phase SiO2 under CuO film. Further studies about the mechanism of PL are still in progress.Electrophoretic deposition is a simple method of preparing CuO thin film. Fully grinded CuO powders are dissolved in ethanol, with a small amount of nitric acid as electrolyte, by full ultrasonic vibrations, thus electrophoretic solution is obtained. Cu and CuO thin films are deposited on Si substrates with an electrophoretic device, then Cu thin films are annealed at 900℃for 30min. The test results show: different granual thin films are found at different electric voltages. After anealed at high temperature in atmosphere, they have almost the same composites, while the morphologys are quite different. The CuO that oxided in the process of electrophoretic deposition has better crystallization quality. |
PDF Full Text Request