La-doped nano-ZnO and the ZnO / La (OH) _3 mixed film of cathodic electrodeposition

Title: La-doped nano-ZnO and the ZnO / La (OH) _3 mixed film of cathodic electrodeposition of
　　Author: Wang Yankun
　　Degree-granting unit: Zhengzhou University
　　Keywords: ZnO nanorods;; electro-deposition;; temperature;; earth;; ZnO / La (OH) _3 mixed film
　　Summary:
　　ZnO as an important wide band gap (3.37 eV), high exciton binding energy (60 meV) of Ⅱ - Ⅵ semiconductor materials. With good light, electricity, magnetism and other properties, has been widely used in light emitting devices, solar cells, gas sensing electrode, piezoelectric sensors and photocatalytic fields. In recent years, rare earth ions (eg Tb, Er, Eu, Dy, Ce)-doped ZnO because of the unique luminescent properties and has attracted many scholars, but most Neodymium magnets studies focused on the substitutional doping of ZnO on , on the rare earth hydroxides and doped ZnO deposition studies were still rare.
　　This paper uses three-electrode potentiostatic electrodeposition technique, using the thermodynamic method of ZnO thin film deposition process temperature on the potential-pH, physical distribution coefficient, ZnO / Zn (OH) 2 solubility and ITO (indium tin oxide, ITO) glass electrode prepared with high c-axis preferred orientation of ZnO nanorod array film and rare earth elements La-doped ZnO / La (OH) 3 were deposited film.
　　Experiment first by 0.1mol / L Zn (NO3) 2 system at different temperatures of the electric potential-pH, composition of the distribution coefficient and ZnO / Zn (OH) 2 solubility thermodynamic method of calculation of the optimal experimental conditions and the final electrodeposition deposition of the product. Then use the CV curve of the deposition process, the current density - time curve, film X-ray powder diffraction, scanning electron microscopy and thermogravimetry - differential thermal thermodynamic experimental results verify the theoretical analysis. Optical study, ZnO thin films in the visible region with a high transmittance (> 80%) and relatively steep absorption edge. Finally, experiments made with zinc nitrate aqueous electrodeposition of ZnO in the reaction mechanism.
　　Using constant potential cathodic electrodeposition control technology, the simple Zn (NO3) 2 solution, the use of hexamethylene tetramine (Hexamethylenetetramine, HMT) as the morphology control reagent, directly in the ITO transparent conductive substrate prepared dense ZnO nanorod array film. X-ray powder diffraction, scanning electron microscopy, energy dispersive spectroscopy, UV - visible transmission spectra and photoluminescence techniques, its crystalline properties, surface morphology, composition, optical properties were studied. The results show that the auxiliary role in the HMT, the preparation of highly c-axis preferred orientation of ZnO nanorods for high-purity single-crystal wurtzite structure, particle size of about 300nm, membrane surface roughness improved significantly. UV - visible transmission spectra of ZnO thin films in the visible region shows a high transmittance (> 80%) and steep absorption edge at room temperature photoluminescence spectra of strong and sharp UV emission peak and a weak green emission peak shows that the ZnO nanorod array film with good crystallinity and excellent luminescence properties.
　　Cathodic potentiostatic electrodeposition technique, containing different concentrations of La3 + ions 0.01M Zn (NO3) 2,0.1 M KNO3 solution prepared La-doped ZnO / La (OH) 3 were deposited film. First, La-NO3-H2O system at 25 ℃ and 70 ℃ under the conditions of potential-pH, composition of the distribution curve and ZnO / La (OH) 3 solubility thermodynamic method to predict the La3 + in the NO3-ion solution in the electric chemical behavior. According to La-NO3-H2O and Zn-NO3-H2O system contrast material is deposited first obtained ZnO, with the solution in the reduction of NO3-ions lead to the electrode surface pH increased, then La (OH) 3 began to deposit with the ZnO on the ITO electrode surface to form a hybrid of the deposited film, co-deposition film La (OH) 3 groups were calculated by the thermal decomposition temperature of roughly 662K. http://www.chinamagnets.biz/Neodymium/Ball-Neodymium-Magnets.php The thermodynamic analysis on ITO electrodes by co-deposition of ZnO / La (OH) 3 thin films were deposited on the membrane and TG - DTA experiments to be confirmed. It was found that with increasing concentrations of La3 + and rapid emergence of two-phase: dispersion of La-doped ZnO flower-like and at the bottom by the La (OH) 3 and ZnO-ceramic composition of the coating. With increasing concentration of La3 +, ZnO / La (OH) 3 films were deposited by the optical surface roughness of the decline due to lower.
　　Degree Year: 2010