共查询到20条相似文献,搜索用时 140 毫秒
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《光学学报》2010,(8)
采用射频磁控溅射法在n型单晶Si(100)衬底上制备Au/Si/Au多层薄膜,并在300℃真空原位退火30min。扫描电子显微镜(SEM)及透射电子显微镜(TEM)观察发现,退火前样品表面是一层平整的薄膜,而退火后样品表面形成均匀分布的岛状纳米颗粒,颗粒直径为10~20nm,面密度约1×1011cm-2。X射线光电子能谱(XPS)及TEM分析表明,退火后样品表面形成单晶结构的AuSix(x=1/2,1/7)纳米颗粒。室温下对退火后样品的光致发光(PL)特性进行测试,样品在580,628和700nm处出现三个发光峰,经过分析这些发光峰与样品表面的SiO2结构,AuSix纳米颗粒周围的悬挂键等缺陷以及样品表面SiO2纳米结构中的无桥联氧等因素有关。 相似文献
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采用XeCl脉冲准分子激光器,在10Pa的Ar气环境下,烧蚀高阻单晶Si靶,分别在距靶3cm的玻璃和单晶Si衬底上制备了纳米Si薄膜. 相应的Raman谱和x射线衍射谱均证实了薄膜中纳米Si晶粒的形成. 扫描电子显微镜图像显示,所形成的薄膜呈均匀的纳米Si晶粒镶嵌结构. 相应的光致发光峰位出现在599nm,峰值半高宽为56nm,与相同参数下以He气为缓冲气体的结果相比,具有较窄的光致发光谱,并显示出谱峰蓝移现象.
关键词:
纳米Si晶粒
脉冲激光烧蚀
薄膜形貌
光致发光 相似文献
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采用自悬浮定向流法制备出Ag2Al复合金属间化合物的纳米微粉,通过透射电子显微镜、X射线衍射仪和X射线能谱仪对纳米微粉的显微结构、粒度、相组成和成分构成进行研究。结果表明:所制备出的复合金属间化合物纳米颗粒呈规则球形,粒径分布在20~110 nm之间;纳米合金颗粒的主要组成相为Ag2Al,并伴有少量的Al;样品中的Ag,Al原子数比约为66.5∶33.5,金属间化合物纳米颗粒中Ag2Al晶粒尺寸约为33 nm,Al的约为21 nm。 相似文献
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在0.6keV Ar+高剂量(~1022/cm2)辐照石墨表面,借助于高分辨透射电子显微镜(HRTEM),发现有六方金刚石纳米晶产生.它们的平均直径介于1—50nm之间,而且晶粒个数约随其直径的增大而直线减少.有趣的是,晶粒具有两种结构模式:直径小于10nm的晶粒为单晶结构,而直径大于10nm的为多晶结构.基于受离子轰击过程特点制约的六方金刚石晶粒成核和成长观点,讨论了这种双重结构的形成性质.
关键词:
离子轰击
六方金刚石纳米晶 相似文献
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为了研究CdS纳米颗粒填充的自支撑多孔硅的光致发光特性,选用电阻率为0.01~0.02Ω·cm的P型硅片,先采用二步阳极氧化法制备自支撑多孔硅,再利用电泳法将CdS纳米颗粒填充入该自支撑多孔硅中.采用扫描电子显微镜、X射线能谱分析、X射线衍射分析、光致发光谱分析对所制备样品的形貌、相结构、组份及发光性能进行研究.实验结果表明:自支撑多孔硅内部成功填充了CdS纳米颗粒,该CdS纳米颗粒衍射峰为(210);CdS纳米颗粒填充的自支撑多孔硅光致发光峰峰位发生红移,且从570nm转移到740nm;电泳时间直接影响CdS纳米颗粒的填充量,导致相关的发光峰强度及发光峰位明显不同. 相似文献
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β-FeSi2作为一种环境友好的半导体材料,颗粒化及非晶化正在成为提高其应用性能和改善薄膜质量、膜基界面失配度的有效途径.利用射频磁控溅射法在单晶Si基体上沉积Fe/Si多层膜,合成纳米β-FeSi2/Si多层结构.通过透射电子显微镜、高分辨电子显微术等分析手段,研究了多层结构和制备工艺之间的相互关系.研究结果表明,采用磁控溅射Fe/Si多层膜的方法,不需要退火就可以直接沉积得到β-FeSi2相小颗粒.β-FeSi2相颗粒尺寸在20 nm以下,小的颗粒尺寸导致发光蓝移,带隙宽度变大,Edg值约为0.94 eV.经过850 ℃的真空退火处理后,β-FeSi2相没有发生改变,颗粒尺寸变大、蓝移效果消失,β-FeSi2相小颗粒的尺寸仍小于100 nm,结构的稳定性较好. 相似文献
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采用高压放电的方式对材料进行击穿,可以方便地制造纳米颗粒.搭建了高压击穿实验装置,对铜丝进行高压击穿实验;分别采用透射电子显微镜(TEM)、扫描电子显微镜(SEM)和元素能谱(EDS)、X射线衍射(XRD)测试,对铜丝击穿丝状物进行了形貌和成份分析.研究了铜丝高压击穿后的物相特性.研究结果发现,在高压作用下铜丝被充分电离,产生丝状分布,其构成为纳米颗粒的凝结;纳米颗粒的直径分布主要集中在30—60nm之间;颗粒产物由铜元素和氧元素组成;它们以单晶Cu,Cu2O和CuO组成混合物;粒径大小、产物成分与铜丝长度、直径及电压等因素相关. 相似文献
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Homogeneous ZnO Nanoparticles by Flame Spray Pyrolysis 总被引:2,自引:0,他引:2
Zinc oxide (ZnO) nanoparticles were made by flame spray pyrolysis (FSP) of zinc acrylate–methanol–acetic acid solution. The effect of solution feed rate on particle specific surface area (SSA) and crystalline size was examined. The average primary particle diameter can be controlled from 10 to 20nm by the solution feed rate. All powders were crystalline zincite. The primary particle diameter observed by transmission electron microscopy (TEM) was in agreement with the equivalent average primary particle diameter calculated from the SSA as well as with the crystalline size calculated from the X-ray diffraction (XRD) patterns for all powders, indicating that the primary particles were rather uniform in diameter and single crystals. Increasing the solution feed rate increases the flame height, and therefore coalescence and/or surface growth was enhanced, resulting in larger primary particles. Compared with ZnO nanoparticles made by other processes, the FSP-made powder exhibits some of the smallest and most homogeneous primary particles. Furthermore, the FSP-made powder has comparable BET equivalent primary particle diameter with but higher crystallinity than sol–gel derived ZnO powders. 相似文献
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A. V. Klochkov V. V. Naletov M. S. Tagirov D. A. Tayurskii A. N. Yudin R. Sh. Zhdanov M. R. Zhdanov A. A. Bukharaev N. I. Nurgazizov 《Applied magnetic resonance》2000,19(2):197-208
Nanocavities with a size of less than 30 nm on the crystal surface of superfine LiYF4 powders and single crystals of the Van Vleck paramagnet LiTmF4 were detected by nuclear magnetic resonance (NMR) cryoporometry and atomic-force microscopy (AFM) and liquid3He NMR cryoporometry. NMR investigations show that the nanocavities are evidently present on the surface of the LiYF4 powder particles. The distribution of nanocavities has two maxima corresponding to the specific porous sizes of 3–5 and 10–15 nm. AFM investigations detect the presence of the nanocavities with sizes in the range 50–300 nm on the surface of powder particles and single crystals. The cases of powder microparticles and of a single crystal differ in the value of the parameter “surface roughness”, which is 14.5 and 11 nm, respectively. The mechanism of creation of nanocavities is proposed and verified by additional investigations with CaF2 powders. 相似文献
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MicrostructureEvolutioninLaserRSCo-baseMetastableAlloyWANGAnan;CHENGShunqi;GUOZhiyao(KunmingUniversityofScienceandTechnology,... 相似文献
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This paper reports the formation and properties of nano-composite pyroelectric thin films. They consist of pyroelectric triglycine sulfate (TGS) single-crystal nano-rods grown inside a highly dense array of alumina pores (about 65 nm diameter and density of 1011 cm−2). The nucleation and growth of the TGS single crystals are obtained by precipitation from a supersaturated aqueous solution. Nucleation is preferred only at the bottom of the pores due to a tight control of temperature, composition and pore diameter. Growth of single crystals with preferred crystallographic orientation is obtained with the aid of an applied electric field. Various crystallographic orientations (1 0 0) (−1 1 0) (−1 2 0) are obtained separately as a single preferred orientation by changing the amplitude of the electric field during crystal growth. The films exhibit ferroelectric behavior. 相似文献
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I. A. Prokhorov Yu. A. Serebryakov I. Zh. Bezbakh B. G. Zakharov V. V. Ratnikov M. P. Shcheglov I. L. Shul’pina 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2009,3(6):936-942
Concentration and structural inhomogeneities in highly doped GaSb(Si) single crystals grown under various conditions of heat
and mass transfer are studied by methods of X-ray topography, high-resolution X-ray diffractometry, and digital image processing.
It is established that the inhomogeneity of crystals is determined by specific features of impurity microsegregation during
growth under conditions of nonstationary convection in a melt and by peculiarities of the dislocation structure of crystals.
The processes related to the initial stage of the decay of the Si supersaturated solid solution in GaSb contribute considerably
to the inhomogeneity of crystals on the micro- and macrolevels. 相似文献
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Yu. I. Chumlyakov I. V. Kireeva E. Yu. Panchenko V. A. Kirillov E. E. Timofeeva I. V. Kretinina Yu. N. Danil’son I. Karaman H. Maier E. Cesari 《Russian Physics Journal》2012,54(8):937-950
The results of investigations into the influence of disperse particles on the temperatures of martensitic transformations
as well as values of thermal and mechanical hysteresis in the FeNiCoAlTa, CoNiGa, NiFeGa, TiNi single crystals are reported.
It is shown that the disperse particles are responsible for refining martensitic crystals and changing their fine twin structure
as compared with the monophase state. This, in turn, affects the values of thermal and mechanical hysteresis and the temperature
range of superelasticity. 相似文献
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Characterization of ultrafine zirconia and iron oxide powders prepared under hydrothermal conditions
Abstract Nanocrystalline zirconia (6-20 nm) and iron oxide (20-80 nm) powders were produced by hydrothermal treatment of corresponding hydroxides and nitrate solutions. The synthesis parameters (temperature, duration, concentration) allow fabrication of ultrafine oxide powders with various particle size and morphology. The smallest particles were produced by short-time (4-7 s) treatment of nitrate solutions (PH ≈ 1). Prepared nanocrystalline powders exhibit high activity in model solid state reactions. 相似文献
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V. T. Bublik S. Yu. Matsnev K. D. Shcherbachev M. V. Mezhennyi M. G. Mil’vidskii V. Ya. Reznik 《Physics of the Solid State》2003,45(10):1918-1925
Diffuse x-ray scattering (DXS) is used to study the formation of microdefects (MDs) in heat-treated dislocation-free large-diameter silicon wafers with vacancies. The DXS method is shown to be efficient for investigating MDs in silicon single crystals. Specific defects, such as impurity clouds, are found to form in the silicon wafers during low-temperature annealing at 450°C. These defects are oxygen-rich regions in the solid solution with diffuse coherent interfaces. In the following stages of decomposition of the supersaturated solid solution, oxide precipitates form inside these regions and the impurity clouds disappear. As a result of the decomposition of the supersaturated solid solution of oxygen, interstitial MDs form in the silicon wafers during multistep heat treatment. These MDs lie in the {110} planes and have nonspherical displacement fields. The volume density and size of MDs forming in the silicon wafers at various stages of the decomposition are determined. 相似文献
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In this report we analyze the causes of gallium microinclusion formation in gallium arsenide single crystals. We present a model in which microinclusions result from the decomposition of a supersaturated solid solution. From experimental data available in the literature and calculated kinetic parameters of the model we demonstrate that microinclusion formation in bulk single crystals follows the mechanism of homogeneous nucleation and Brownian coalescence of precipitated liquid gallium metal.Translated from Izvestiya Vysshikh Uchbenykh Zavedenii, Fizika, No. 2, pp. 32–35, February, 1988. 相似文献
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A. E. Cordero-Borboa E. Sterling-Black A. Gmez-Corts A. Vzquez-Zavala 《Applied Surface Science》2003,220(1-4):169-174
An X-ray diffraction study was carried out on powders of a series of catalysts prepared from aqueous solutions of H2PtCl6 and PdCl4 and amorphous SiO2 with different concentrations in weight of Pt and Pd at about 4% in overall metallic weight. Measurements of the position of high angle Bragg reflections in the diffractograms show evidence of the fact that the small catalyst particles are bi-metallic Pt-Pd crystals having a face-centred cubic Bravais lattice. The lattice constant of these crystals was found to change with the relative concentration of Pt and Pd by following the Vegard’s rule. This correlation leads to the conclusion that the bi-metallic catalyst particles are made of a single solid solution of Pt and Pd atoms in the whole range of relative concentrations. Relative concentrations of these metals in the samples under study were determined by using energy dispersive X-ray spectrometry and their values were found to be close to the stochiometric relative concentrations in weight of the metals in the precursor aqueous solution. An average size of about 96 Å was estimated for the bi-metallic particles from the full-width at half-maximum value measured for the (2 0 0) diffractometric curve. 相似文献