共查询到19条相似文献,搜索用时 140 毫秒
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为了得到准确的In2O3晶体电子结构, 本文分别采用GGA, GGA+U, HSE06的方法计算了电子结构, 并进行了G0W0修正, 通过比较计算结果, 得到HSE06+G0W0方法计算得到的禁带宽带最接近实验结果. 在此基础上使用Hedin的G0W0近似方法和Bethe-Salpeter方程计算得到了In2O3晶体的光学性质, 计算结果与实验结果吻合很好, 在此基础上通过对准粒子能带结构、光学跃迁矩阵和光学吸收谱的分析, 给出了In2O3晶体的光学跃迁机理. 相似文献
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应用射频磁控共溅射方法在石英玻璃和抛光硅片上制备了InP/SiO2复合薄膜,并在几种条件下对这些薄膜进行退火.X射线光电子能谱和卢瑟福背散射实验结果表明,复合薄膜中InP和SiO2的化学组分都大体上符合化学计量配比.X射线衍射和激光喇曼谱实验结果都证实了复合薄膜中形成了InP纳米晶粒.磷气氛保护下的高温(520℃)退火可以消除复合薄膜中残存的In和In2O3并得到了纯InP/SiO2纳米复合薄膜.实验观察到了室温下纳米复合薄膜的明显的光学吸收边蓝移现象和光学非线性的极大增强
关键词:
InP
纳米晶粒
微观结构
光学性质 相似文献
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磁通钉扎性能对GdBa2Cu3O7-δ超导块材的实际应用具有重要的影响, 而引入合适的第二相粒子可以改善GdBa2Cu3O7-δ 超导块材的磁通钉扎性能.本文采用顶部籽晶熔融织构法成功地制备出纳米微粒BaFe12O19(<100 nm)掺杂的超导块材, 样品的最终组分为Gd123+ 0.4 Gd211+ x BaFe12O19 (x=0, 0.2 mol%, 0.4 mol%, 0.8 mol%)+ 10 wt%Ag2O+ 0.5 wt%Pt. 通过研究不同掺杂量的BaFe12O19微粒对GdBa2Cu3O7-δ 超导块材微观结构和超导性能的影响, 结果表明当掺杂量为0.2 mol%时, 样品的临界电流密度几乎在整个外加磁场下都有明显的提高.在零场下, 临界电流密度达到5.5× 104 A/cm2. 纳米微粒BaFe12O19不仅可以保持掺杂前的化学组成, 作为有效的钉扎中心存在于超导块材中, 并且能够改善Gd2BaCuO5粒子的分布和细化Gd2BaCuO5粒子, 使Gd2BaCuO5粒子的平均粒径由未掺杂时的1.4 μ m减小到掺杂后的0.79 μ m, 进而提高了超导块材的临界电流密度和俘获磁场, 明显提高了GdBa2Cu3O7-δ 超导块材的超导性能.临界温度TC也有所提升, 并能够维持在92.5 K左右. 该结果为进一步研究纳米磁通钉扎中心的引入并改善GdBa2Cu3O7-δ 超导块材的性能有着重要的意义. 相似文献
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采用加热分解油酸铁法制备了Fe3O4磁性纳米颗粒,并用有机模板和反相微乳液相结合的方法将磁性纳米颗粒包裹在多孔二氧化硅中.用红外光谱(FTIR)研究了不同的处理方式对油酸铁表面官能团的影响及油酸的反应浓度和加热分解油酸铁的过程中升温速率对Fe3O4纳米颗粒的影响.结果表明,用乙醇和丙酮处理后的固态蜡状油酸铁表面的油酸基团会受到损害,将不利于加热分解时形成单分散性的Fe3O4纳
关键词:
3O4纳米颗粒')" href="#">Fe3O4纳米颗粒
2包裹')" href="#">多孔SiO2包裹
反相微乳液法
油酸铁 相似文献
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Al2O3介质薄膜与纳米Ag颗粒构成的复合结构,被应用于表面增强Raman散射探测实验中,其中Al2O3介质薄膜对纳米Ag颗粒的吸收谱及增强Raman散射光谱的影响被特别关注.该复合结构的光学特性表征出纳米Ag颗粒的偶极振荡特性.从光吸收谱中可以看到,其共振吸收谱随Al2O3介质薄膜厚度增加而在整个谱域上发生红移,表明纳米Ag颗粒的周围介电常数随Al2O3介质薄膜厚度的增加而增大.采用罗丹明6G作为探针原子,6个Raman特征峰的平均增益值作为表征表面增强Raman散射衬底增益程度的量度.实验结果表明,Al2O3介质薄膜层的引入提高了纳米Ag颗粒的衬底介电常数,并引起了散射共振的增强,从而使表面增强Raman散射强度提高.
关键词:
纳米Ag薄膜
共振吸收
表面增强Raman散射
介电常数 相似文献
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Sodky Hamed Mohamed 《哲学杂志》2013,93(27):3598-3612
Oxygen-deficient (OD) and nearly stoichiometric (NST) ZnO and In2O3 nanowires/nanoparticles were synthesized by chemical vapor deposition on Au-coated silicon substrates. The OD ZnO and OD In2O3 nanowires were synthesized at 750 and 950°C, respectively, using Ar flow at ambient pressure. A mixture of flowing Ar and O2 was used for synthesizing NST ZnO nanowires and NST In2O3 nanoparticles. Growth of OD ZnO nanowires and NST In2O3 nanoparticles was found to be via a vapor–solid (VS) mechanism and the growth of NST ZnO nanowires was via a vapor–liquid–solid mechanism (VLS). However, it was uncertain whether the growth of OD In2O3 nanowires was via a VS or VLS mechanism. The optical constants, thickness and surface roughness of the prepared nanostructured films were determined by spectroscopic ellipsometry measurements. A three-layered model was used to fit the calculated data to the experimental ellipsometric spectra. The refractive index of OD ZnO, NST ZnO nanowires and NST In2O3 nanoparticles films displayed normal dispersion behavior. The calculated optical band gap values for OD ZnO, NST ZnO, OD In2O3 nanowires and NST In2O3 nanoparticles films were 3.03, 3.55, 2.81 and 3.52?eV, respectively. 相似文献
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P. Malar 《Journal of Physics and Chemistry of Solids》2005,66(11):1928-1932
CuInSe2/In2O3 structures were formed by depositing CuInSe2 films by stepwise flash evaporation onto In2O3 films, which were grown by DC reactive sputtering of In target in presence of (Ar+O2) gas mixture. Phase purity of the CuInSe2 and In2O3 films was confirmed by Transmission Electron Microscopy (TEM) studies. X-ray diffraction (XRD) results on CuInSe2/In2O3/glass structures showed sharp peaks corresponding to (112) plane of CuInSe2 and (222) plane of In2O3. Rutherford Backscattering Spectrometry (RBS) investigations were carried out on CuInSe2/In2O3/Si structures in order to characterize the interface between In2O3 and CuInSe2. The results show that the CuInSe2 films were near stoichoimetric and In2O3 films had oxygen deficient composition. CuInSe2/In2O3 interface was found to include a ∼20 nm thick region consisting of copper, indium and oxygen. Also, the In2O3/Si interface showed the formation of ∼20 nm thick region consisting of silicon, indium and oxygen. The results are explained on the basis of diffusion/reaction taking place at the respective interfaces. 相似文献
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Nonlinear optical properties of Fe2O3 nanoparticles were investigated by the signal-beam Z-scan technique with Ar+ and Ne–He lasers. The largest reported effective nonlinear coefficient, n2=−8.07×10−7 cm2/W, was obtained. It is demonstrated that the nonlinear optical response originals from quantum confinement effect. 相似文献
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M. M. Mikhailov V. V. Neshchimenko N. V. Dedov Chundong Li Shiyu He 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2011,5(6):1152-1161
The effect of the modification of ZnO powders by ZrO2 and Al2O3 nanoparticles with a concentration of 1–30 wt % is investigated by diffuse reflectance spectra within the wavelength range
0.2 to 2.5 μm before and after 100 keV proton and electron irradiation. It has been established that the introduction of nanoparticles
enhances the optical stability of the pigments under proton irradiation, but reduces it under electron irradiation. Samples
modified by 5 wt % of ZrO2 nanoparticles have the highest stability of optical properties after proton exposure. The degradation of optical properties
under electron irradiation is not high for this concentration of nanoparticles. A decrease in the absorption of pigments modified
with nanoparticles after proton exposure is determined by a decrease in the intensity of bands located in the UV and visible
regions. After electron exposure the absorption bands have a high intensity in the whole spectrum range. 相似文献
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Octahedral In2O3 crystals were synthesized by evaporation of a mixture of In2O3 and graphite in a horizontal double-tube system. By adjusting the experimental conditions, In2O3 nanowires and nanobelts were also obtained. The microstructures of the resultant In2O3 materials were characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), selected-area electron diffraction (SAED), X-ray diffraction. In addition, the growth mechanism of the octahedral In2O3 crystals was discussed in detail. 相似文献
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In2O3 is introduced into TiO2 by sol-gel method to improve the response/recovery rate and expand the operating temperature, when the In2O3-TiO2 mixed system is exposed to H2/O2. The sensor is fabricated by thick film technology. Influence of In2O3 on the film phase composition, microstructure and sensing characteristics is discussed. Dynamic response properties show that the operating temperature of the mixed system is at 500-800 °C, which is about 600-800 °C for pure TiO2. Response time of the sensor is about 200-260 ms (millisecond) while recovery time is in a narrow range of 60-280 ms at 600-800 °C. The promoting mechanism is suggested to arise from the introduction of In2O3 and grain size effect of the sensing film. Then In2O3-TiO2 thick films are surface-modified by Pt using chloroplatinic acid. The promoting effect of Pt dispersed on the mixed system is also investigated. 相似文献
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R.Y. Hong T.T. Pan Y.P. Han H.Z. Li J. Ding Sijin Han 《Journal of magnetism and magnetic materials》2007
Methods to synthesize magnetic Fe3O4 nanoparticles and to modify the nanoparticle surface are presented in this paper. In these methods, Fe3O4 nanoparticles were prepared by co-precipitation, and the aging of nanoparticles was improved by applied magnetic field. The obtained nanoparticles were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray powder diffraction (XRD), and vibrating sample magnetometer (VSM). Thereafter, to enhance the compatibility between nanoparticles and water, an effective surface modification method was developed by grafting acrylic acid onto the nanoparticle surface. FT-IR, XRD, transmission electron microscopy (TEM), and thermogravimetry (TG) were used to characterize the resultant sample. The testing results indicated that the polyacrylic acid chains have been covalently bonded to the surface of magnetic Fe3O4 nanoparticles. The effects of initiator dosage, monomer concentration, and reaction temperature on the characteristics of surface-modified Fe3O4 nanoparticles were investigated. Moreover, the Fe3O4-g-PAA hybrid nanoparticles were dispersed in water to form ferrofluids (FFs). The obtained FFs were characterized by UV–vis spectrophotometer, Gouy magnetic balance and laser particle-size analyzer. The testing results showed that the high-concentration FF had excellent stability, with high susceptibility and high saturation magnetization. The rheological properties of the FFs were also investigated using a rotating rheometer. 相似文献
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Monica Sorescu L Diamandescu D Tarabasanu-Mihaila 《Journal of Physics and Chemistry of Solids》2004,65(10):1719-1725
α-Fe2O3-In2O3 mixed oxide nanoparticles system has been synthesized by hydrothermal supercritical and postannealing route, starting with (1−x)Fe(NO3)3·9H2O·xIn(NO3)3·5H2O aqueous solution (x=0-1). X-ray diffraction and Mössbauer spectroscopy have been used to study the phase structure and substitutions in the nanosized samples. The concentration regions for the existence of the solid solutions in the α-Fe2O3-In2O3 nanoparticle system together with the solubility limits of In3+ ions in the hematite lattice and of Fe3+ ions in the cubic In2O3 structure have been evidenced. In general, the substitution level is considerably lower than the nominal concentration x. A justification of the processes leading to the formation of iron and indium phases in the investigated supercritical hydrothermal system has been given. 相似文献
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Daisuke Yamashita Tsuyoshi Yoshioka So Nishida Tomoyuki Yamamoto 《Physica B: Condensed Matter》2012,407(22):4485-4488
The valence band electronic structures of Mn- and/or Fe-doped In2O3, i.e., In2O3:Mn, In2O3:Fe, and In2O3:(Mn, Fe), are investigated by photoemission yield measurements. Significant changes are observed in the threshold energy of photoemission, depending on the doped magnetic ions, which indicates that an additional occupied band appears above the top of the valence band of In2O3 owing to doping with Mn and/or Fe ions. It is confirmed that the order of the threshold energies of photoemission, EPET, is EPET(In2O3:Mn)<EPET(In2O3:(Mn, Fe))<EPET(In2O3:Fe)<EPET(In2O3). To gain a better understanding of these results, first-principles molecular orbital calculations are also carried out, which successfully explain the observed changes in the photoemission threshold energies. 相似文献