Synthesis and Characterization of SnO2 One-dimensional Nanostructures

Single-crystalline SnO2 nanowires have been successfully prepared in large scale on Au-coated silicon substrate by heating the mixture of self-made high-purity SnO2 powders and graphite powders at 900℃. Besides the line type nanowires some more features were observed. The products were characterized by means of X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) and Raman spectrum techniques. The results indicate that the tin dioxide nanowires have a rutile structure with diameters ranging from 30 to 120 nm and lengths up to several tens of micrometers. The possible mechanism of the growth and reaction for the nanowires was also discussed.     

Fe/ZnO(0001)界面的同步辐射光电子能谱研究

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.     

X-Ray Magnetic Circular Dichroism Measurement of Fe-Co Alloy Films Prepared by Electrodeposition

The macro- and micro-magnetic properties of Fe-Co alloy films eletrodeposited on CaAs（100） are studied by synchrotron radiation x-ray magnetic circular dichroism （XMCD） in combination with the magneto-optical Kerr effect （MOKE） measurements and magnetic force microscopy （MFM）. The orbital and spin magnetic moments of each element in the Fe-Co alloy are determined by the sum rules of XMCD. Element-specific hysteresis loops （ESHL） are obtained by recording the La MCD signals as a function of applied magnetic field. MOKE results reveal that the amorphous films are magnetically isotropic in the surface plane. The MFM image shows that the dimension of the magnetic domains is about 1-2 #m, which is much larger than that of the grains, indicating that there are intergranular correlations among these grains. Both ESHL and MOKE hysteresis loops indicate the strong ferromagnetic coupling of Fe and Co in the alloy films.     

Co-Ni合金薄膜的电化学外延及同步辐射XMCD研究

采用电化学循环伏安法在单晶GaAs(001)衬底上外延沉积了Co-Ni二元合金薄膜. 扫描电子显微镜观察结果显示, 薄膜厚度约180 nm, 其表面由约40 nm大小的颗粒组成. 用X射线荧光法确定了薄膜的组分为Co66Ni34, XRD确定了其为面心立方结构. 用同步辐射圆偏振软X射线分别测量了样品中Co和Ni的吸收谱(XAS), 从而得到X射线磁性圆二色(XMCD)谱, 通过加和定则分别计算出了合金中Co和Ni的轨道磁矩和自旋磁矩, 与纯的Co和Ni样品相比, 它们都有不同程度的增加.     

循环伏安法制备Ag纳米线阵列

In this paper, highly ordered anodic aluminum oxide (AAO) template with hexagonal close-packed arrays was successfully fabricated through a two-step anodization process. Ag nanowire arrays with high aspect ratio were prepared using cyclic voltammetry within the confined nanochannels of AAO template. In addition, standing Ag nanowire arrays free-support of templates were also fabricated successfully by cyclic voltammetry method. The micrographs and crystal structures of Ag nanowires were studied by field emission scanning electron microscope (FESEM) and X-ray diffraction (XRD). FESEM observation showed that the Ag nanowire arrays with high aspect ratio lie orderly on the surface of the substrate. The diameter of the Ag nanowire is about 60 nm and the length up to 30 μm or more. While the controlled nanowire arrays exhibit highly ordered structure in large area and the standing Ag nanowire in the array has the length of 1 μm and good orientation. XRD results illustrated that the Ag nanowires in the arrays deposited by cyclic voltammetry method have a face centered cubic structure and are preferentially oriented in the (220) direction.     

Fe/ZnO (0001)体系界面相互作用中薄膜厚度效应的光电子能谱研究

利用同步辐射光电子能谱(SRPES)和X射线光电子能谱(XPS)技术,系统研究了室温下Fe/ZnO界面形成过程中Fe薄膜与氧结尾的ZnO(000 1 )衬底之间的相互作用,结果显示初始沉积的Fe明显被表面氧氧化为Fe²⁺离子,在Fe覆盖度为0—3 nm的范围内,分别观察到与界面电荷传输、化学反应以及薄膜磁性相关的三个有意义的临界厚度,这一结果将有助于基于Fe/ZnO界面的相关器件的设计和研发. 关键词： Fe/ZnO 界面作用 同步辐射光电子能谱 X射线光电子能谱     

Fe/ZnO(0001-)界面的同步辐射光电子能谱研究

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2A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1．5A）的Fe被ZnO（0001）面的外层0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5．1A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0．2A时达到最小值4．5．eV，偶极层形成后逐渐稳定在4．9eV．     

单晶ZnO纳米线的合成和生长机理研究

用化学气相输运(CVT)方法合成了直径在20～120nm呈单晶结构的ZnO纳米线.利用场发射扫描电 镜(FESEM)、高分辨透射电镜(HRTEM)以及选区电子衍射(SAED)等技术对ZnO纳米线的生长机理和结构进行 了系统研究,结果表明,纳米线的成核与Au Zn合金催化颗粒的饱和度有直接的关系,先饱和的颗粒上纳米线首 先成核.纳米线顶端合金颗粒组成的变化是导致纳米线生长终止的重要原因,大量纳米线的生长不是同时进行 的.本工作提供了支持纳米线气液固(V L S)生长机理的新实验证据,提出了氧化物纳米线的生长机理.     

电沉积铁族薄膜的磁性圆二色研究

采用循环伏安法在GaAs(100)单晶表面电沉积了铁族金属单质薄膜. 扫描电子显微镜(SEM)结果显示, Fe族金属薄膜的晶粒较小, 薄膜平整度较高。通过X射线衍射(XRD)谱分析了Fe, Co, Ni在GaAs(100)晶面上的外延生长. 使用磁光克尔效应装置研究了Fe族金属薄膜的宏观磁性, 用同步辐射圆偏振软X射线测量了铁族单质磁性薄膜的吸收谱, 获得了X射线磁性圆二色谱, 并通过加和定则计算了磁性薄膜中Fe族金属原子的轨道磁距和自旋磁矩.     

Fe/ZnO (0001)体系界面相互作用中薄膜厚度效应的光电子能谱研究

利用同步辐射光电子能谱(SRPES)和X射线光电子能谱(XPS)技术,系统研究了室温下Fe/ZnO界面形成过程中Fe薄膜与氧结尾的ZnO(000 1 )衬底之间的相互作用,结果显示初始沉积的Fe明显被表面氧氧化为Fe²⁺离子,在Fe覆盖度为0—3 nm的范围内,分别观察到与界面电荷传输、化学反应以及薄膜磁性相关的三个有意义的临界厚度,这一结果将有助于基于Fe/ZnO界面的相关器件的设计和研发.