提出了一种在极低的生长速率下(例如分子外延技术),以SrTi O3为代表的ABO3型氧化物薄膜的生长机理,并针对这一生长机制,给出了基于Monte Carlo方法的三维模型和模拟算法.模拟基于Solid on Solid模型,并采用周期性的边界条件;模拟中通过...提出了一种在极低的生长速率下(例如分子外延技术),以SrTi O3为代表的ABO3型氧化物薄膜的生长机理,并针对这一生长机制,给出了基于Monte Carlo方法的三维模型和模拟算法.模拟基于Solid on Solid模型,并采用周期性的边界条件;模拟中通过库仑作用势引入了基底对沉积分子的影响;Monte Carlo事件由沉积事件、扩散事件、吸附成核事件组成;分子扩散能力与扩散激活能相关.展开更多
The effects of rare-earth La_2O_3 addition on microstructures and electrical properties of SrTiO_3 ceramics were investigated. Semiconductor SrTiO_3-based voltage-sensing and dielectric dual functional ceramics was pr...The effects of rare-earth La_2O_3 addition on microstructures and electrical properties of SrTiO_3 ceramics were investigated. Semiconductor SrTiO_3-based voltage-sensing and dielectric dual functional ceramics was prepared by a single step sintering technology in this study, and the effects of the content of La_2O_3 on characteristics of the product were discussed in terms of microstructures and electrical properties of materials. The results show that SrTiO_3-based ceramics doped with La_2O_3 exhibits more homogeneous grain distribution, greater grain size, and excellent voltage sensing and dielectric characteristics than those without La_2O_3 doping. The samples doped with 1 1% La_2O_3 were sintered at 1420 ℃ in N_2+C weak reducing atmosphere. The average grain size of the samples doped with La_2O_3 is 40 μm, the breakdown voltage of 19.7 V·mm^(-1), the nonlinear exponent of 7.2, and dielectric constant of 22500. The results reveal that final products are suitable to use in low operating voltage.展开更多
Lanthanum and nitrogen co-doped SrTiO_3 was prepared by a mechanochemical reaction using SrTiO_3, urea and La_2O_3 as the raw materials. The samples were characterized by X-ray diffraction, X-ray photoelectron spectro...Lanthanum and nitrogen co-doped SrTiO_3 was prepared by a mechanochemical reaction using SrTiO_3, urea and La_2O_3 as the raw materials. The samples were characterized by X-ray diffraction, X-ray photoelectron spectrometer, transmission electron microscopy, and nitrogen adsorption-desorption isotherm measurements. Lanthanum doping could increase the doping content of nitrogen in the sample. The sample prepared with 0.2 mol% La_2O_3, 22 mol% urea and 77.8 mol% SrTiO_3 by mechanochemical reaction, which has nearly the same nitrogen and lanthanum doping fractions, exhibited high photocatalytic activities. Under the irradiation of light with wavelength larger than 400, and 290 nm, the photocatalytic activity of nitrogen and lanthanum co-doped SrTiO_3 were 2.6 and 2 times greater than that of pure SrTiO_3.展开更多
基金Project supported by Science and Technology Foundation of Yunnan Province (2002GG-09)
文摘The effects of rare-earth La_2O_3 addition on microstructures and electrical properties of SrTiO_3 ceramics were investigated. Semiconductor SrTiO_3-based voltage-sensing and dielectric dual functional ceramics was prepared by a single step sintering technology in this study, and the effects of the content of La_2O_3 on characteristics of the product were discussed in terms of microstructures and electrical properties of materials. The results show that SrTiO_3-based ceramics doped with La_2O_3 exhibits more homogeneous grain distribution, greater grain size, and excellent voltage sensing and dielectric characteristics than those without La_2O_3 doping. The samples doped with 1 1% La_2O_3 were sintered at 1420 ℃ in N_2+C weak reducing atmosphere. The average grain size of the samples doped with La_2O_3 is 40 μm, the breakdown voltage of 19.7 V·mm^(-1), the nonlinear exponent of 7.2, and dielectric constant of 22500. The results reveal that final products are suitable to use in low operating voltage.
文摘Lanthanum and nitrogen co-doped SrTiO_3 was prepared by a mechanochemical reaction using SrTiO_3, urea and La_2O_3 as the raw materials. The samples were characterized by X-ray diffraction, X-ray photoelectron spectrometer, transmission electron microscopy, and nitrogen adsorption-desorption isotherm measurements. Lanthanum doping could increase the doping content of nitrogen in the sample. The sample prepared with 0.2 mol% La_2O_3, 22 mol% urea and 77.8 mol% SrTiO_3 by mechanochemical reaction, which has nearly the same nitrogen and lanthanum doping fractions, exhibited high photocatalytic activities. Under the irradiation of light with wavelength larger than 400, and 290 nm, the photocatalytic activity of nitrogen and lanthanum co-doped SrTiO_3 were 2.6 and 2 times greater than that of pure SrTiO_3.
