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941.
942.
采用阴极还原方法,在透明导电玻璃(ITO)上制备了高c轴择优取向的ZnO薄膜.通过X射线衍射、扫描电子显微镜等表征技术,研究了沉积电流对ZnO薄膜的结构、应力状态及表面形貌的影响;利用光致荧光光谱及透射光谱等分析方法,探讨了沉积电流变化对ZnO薄膜的光学性能的影响.研究结果显示:各沉积电流下均可制得高c轴取向的ZnO薄膜;薄膜表面形貌受电流的影响较大;从透射谱可以看出,薄膜在可见光波段有较高透射率,且薄膜厚度随沉积电流的增大而增大.光致荧光测量表明,电化学沉积的ZnO薄膜具有明显的带隙展宽.而且,随着沉积电流的增加,带隙发光强度逐渐减弱,缺陷发光逐渐增强. 相似文献
943.
Based on the framework of effective-mass approximation and variational approach, the luminescent properties are investigated theoretically in self-formed wurtzite GaN/AlxGa1−xN single-quantum dots (QDs). Considering the three-dimensional (3D) confinement of electron and hole pair and the strong built-in electric field effects, the exciton binding energy, the emission wavelength and the oscillator strength are calculated with and without the built-in electric field in detail. The results elucidate that the strong built-in electric field has a significant influence on luminescent properties of GaN/AlxGa1−xN QDs. 相似文献
944.
Composite ZnO/Ag nanoparticles have been formed via the photocatalytic reduction of silver nitrate over the ZnO nanocrystals,
their optical, electrophysical and photochemical properties have been investigated. Mie theory has been applied to analyze
the structure of the absorption spectra of ZnO/Ag nanocomposite. The irradiation effects upon the optical properties of ZnO/Ag
nanostructure have been investigated. It has been found that the irradiation of ZnO/Ag nanoparticles results in electrons
accumulation by both the semiconductor and the metallic components of the nanocomposite. It has been found that silver nitrate
can be photochemically deposited onto the surface of ZnO nanoparticles under the illumination with the visible light in the
presence of the sensitizer – methylene blue. Kinetics of the sensitized Ag(I) photoredution has been studied. It has been
concluded that the key stage of this process is the electron injection from singlet-excited methylene blue molecule into ZnO
nanoparticle. 相似文献
945.
Lianhai Lu Shuang Hu Ho-In Lee Christof Wöll Roland A. Fischer 《Journal of nanoparticle research》2007,9(3):491-496
Cu nanoparticles were formed on surface of nano-ZnO by UV light induced photoreduction of CuCl2 in methanol solution suspended with ZnO nanoparticles. By controlling the reaction conditions, the average size of the produced
copper nanocrystal can be fine-tuned in the range of 10–200 nm. At constant UV irradiation, the Cu nanocrystals gradually
grew up as the initial concentration of copper cation was increased, showing that the in situ formed Cu nanoparticles act as a bridge to facilitate the transferring of photoexcited electrons from ZnO surface to Cu2+ in solution. A Redox property was also proved for the Cu nanoparticles. 相似文献
946.
利用同步辐射光电子能谱研究了Fe/ZnO生长模式、界面化学反应和电子结构.结果表明,Fe在ZnO(0001)表面以类SK模式生长(单层加岛状生长).当沉积约2?的Fe后,生长模式开始从二维层状生长转变成混合模式生长.界面价带谱和Fe3p芯能级谱的分析表明,在低覆盖度下,约有一个原子层(约1.5?)的Fe被ZnO(0001)面的外层O原子氧化,随着沉积厚度的增加,金属态Fe的信号逐渐增强.当吸附了5.1?的Fe时,出现了较强的金属Fe的Fermi边,说明出现了Fe的金属态.此外,在Fe原子吸附过程中,样品功函数在Fe厚度为0.2?时达到最小值4.5eV,偶极层形成后逐渐稳定在4.9eV. 相似文献
947.
S. Chakrabarti B. Doggett R. OHaire E. McGlynn M.O. Henry A. Meaney J.-P. Mosnier 《Superlattices and Microstructures》2007,42(1-6):21
The crystalline, optical and electrical properties of N-doped ZnO thin films were measured using X-ray diffraction, photoluminescence and Hall effect apparatus, respectively. The samples were grown using pulsed laser deposition on sapphire substrates coated priorly with ZnO buffer layers. For the purpose of acceptor doping, an electron cyclotron resonance (ECR) plasma source operated as a low-energy ion source was used for nitrogen incorporation in the samples. The X-ray diffraction analyses indicated some deterioration of the ZnO thin film with nitrogen incorporation. Temperature-dependent Van der Pauw measurements showed consistent p-type behavior over the measured temperature range of 200–450 K, with typical room temperature hole concentrations and mobilities of 5×1015 cm−3 and 7 cm2/V s, respectively. Low temperature photoluminescence spectra consisted of a broad emission band centered around 3.2 eV. This emission is characterized by the absence of the green deep-defect band and the presence of a band around 3.32 eV. 相似文献
948.
A.G. Rolo J. Ayres de Campos T. Viseu T. de Lacerda-Arso M.F. Cerqueira 《Superlattices and Microstructures》2007,42(1-6):265
In this work, a study of the structure and optical properties of undoped ZnO thin films produced by r.f. magnetron sputtering technique as a function of the growth parameters is reported. Modification under annealing conditions is also analysed. Raman spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction and optical transmittance have been used. From the position of the (002) X-ray diffraction peak and the E2 (high) mode detected in Raman spectra, the residual stress both in the as-grown and in the annealed samples has been estimated. 相似文献
949.
Crystalline ZnO nanoparticles were synthesized by mechanochemical method. Mechanochemical processing involves the mechanical activation of solid-state displacement reactions at low temperatures in a ball mill. Statistical design was used to investigate the effect of main parameters (i.e. time, milling rate and calcination temperature) on ZnO crystallite size and morphology. After annealing at 400 °C in air, zinc oxide (ZnO) nanoparticles were obtained. The milled powders are analyzed by X-ray diffraction (XRD), TG/DTA and transmission electron microscope (TEM).The crystallite size of ZnO samples calculated from XRD is consistent with the TEM images and estimated to be less than 20 nm. The optical properties of the samples were studied by UV-vis spectrophotometer. 相似文献
950.
Fan Li 《Journal of luminescence》2007,124(1):162-166
ZnO thin films were deposited with the addition of H2 to the reaction gas using the atmospheric-pressure metal organic chemical vapor deposition method. The incorporation and outdiffusion of hydrogen in ZnO films were investigated by comparing the intensity of the hydrogen-related bound-exciton peak (I4: 3.363 eV) in the photoluminescence spectrum. The intensity of I4 peak was found to be the strongest in the ZnO film deposited at 680 °C with H2 present. However, for the ZnO films prepared at the same temperature 680 °C but without H2 present and at the higher temperature of 900 °C with H2 present, respectively, the I4 peak was just a minor shoulder of another bound-exciton peak (I8: 3.359 eV). The intensity of I4 peak in the ZnO films deposited with H2 present was found to decrease with the increasing of annealing temperature. These results suggest that it is difficult for hydrogen to incorporate into ZnO thin films grown at high temperatures even in the hydrogen-present ambient. 相似文献