中间层Re的加入对覆膜钡钨阴极性能的改善

研究了一种新型的覆膜钡钨阴极——双层膜(Os-W/Re膜)钡钨阴极.对这种新型阴极的发射性能进行了测试，重点对其老炼前后表面薄膜的微观形貌进行了分析，表明中间层Re膜的加入使覆膜钡钨阴极的性能得到了改善.通过对Os-W双元合金膜钡钨阴极和Os-W/Re双层膜钡钨阴极发射特性的比较，发现Os-W/Re双层膜阴极的直流发射性能好于Os-W合金膜阴极.对两种阴极激活后发射表面的X射线光电子能谱分析表明，Os-W/Re双层膜阴极激活后表面形成的三元合金膜是其发射特性优于Os-W合金膜阴极的主要原因.应用扫描电子显微镜分析比较两种阴极激活老炼后的表面状态，结果表明：Os-W合金膜阴极在老炼一段时间后，其表面薄膜出现开裂，这会导致阴极发射均匀性下降；而Os-W/Re双层膜阴极在同样老炼条件下，发射表面薄膜均匀并保持完整，从而确保覆膜钡钨阴极发射均匀性和工作可靠性. 关键词： 双层膜钡钨阴极 Os-W/Re膜 Os-W膜 薄膜开裂     

用干涉方法测量薄膜应力

基于基片弯曲法和牛顿环的基本原理,使用He-Ne激光器、扩束镜、凸透镜和带分光镜的移测显微镜,搭建了薄膜应力测量装置.采用直流溅射法制备了厚度为30~144 nm的银薄膜,衬底采用厚度为0.15 mm、直径为18 mm的圆形玻璃片.实验发现,薄膜厚度对银薄膜的内应力有显著的影响,在薄膜厚度很小时,随着薄膜厚度的增加,应力迅速增大,达到最大值后,随着厚度的继续增加,薄膜应力下降较快并趋于稳定值.     

La0.82Te0.18MnO3薄膜的输运特性和光诱导效应

用脉冲激光沉积法制备了非金属Te掺杂的钙钛矿锰氧化物La_0.82Te_0.18MnO₃单晶薄膜.该薄膜从83 K升温至373 K过程中发生金属-绝缘体相变，转变点温度为283 K.其电阻率在T<T_MI时符合电子-电子、电子-磁振子散射公式；在T>T_MI时为小极化子输运.薄膜在低温段连续激光(波长为532 nm，40 mW)作用下电阻率显著增大，电阻变化率在253 K达到最大值51.1%,该变化率远大于相同条件下的空穴掺杂材料；在高温段产生了较小的光电导，电阻变化率小于10%.这些现象主要与激光激励下自旋系统和小极化子的变化有关.La_0.82Te_0.18MnO₃薄膜在激光诱导下具有明显的与自旋相关的弛豫现象.激光开始作用时薄膜电阻率随时间的变化符合指数关系. 关键词： 0.82Te_0.18MnO₃薄膜')" href="#">La_0.82Te_0.18MnO₃薄膜 光诱导 输运特性 电子掺杂     

生长温度对磁控溅射ZnO薄膜的结晶特性和光学性能的影响

采用反应射频磁控溅射方法，在Si (100) 基片上制备了具有高c轴择优取向的ZnO薄膜.利用 原子力显微镜、透射电子显微镜、X射线衍射分析、拉曼光谱等表征技术，研究了沉积温度 对ZnO薄膜的表面形貌、晶粒尺度、应力状态等结晶性能的影响；通过沉积温度对透射光谱 和光致荧光光谱的影响，探讨了ZnO薄膜的结晶特性与光学性能之间的关系.研究结果显示， 在室温至500℃的范围内，ZnO薄膜的晶粒尺寸随沉积温度的增加而增加，在沉积温度为500 ℃时达到最大；当沉积温度为750℃时，ZnO薄膜的晶粒尺度有所减小；在室温至750℃的范 围内，薄膜中ZnO晶粒与Si基体之间均存在着相对固定的外延关系；在沉积温度低于500℃时 ，制备的ZnO薄膜处于压应变状态，而750℃时沉积的薄膜表现为张应变状态.沉积温度的不 同导致ZnO薄膜的折射率、消光系数、光学禁带宽度以及光致荧光特性的变化，沉积温度对 紫外光致荧光特性起着决定性的作用.此外，探讨了影响薄膜近紫外光致荧光发射的可能因 素. 关键词： ZnO薄膜 表面形貌 微观结构 光学常数     

Assessment of thermal expansion coefficient of methylsilsesquioxane thin film

For the methylsilsesquioxane film whose optical birefringence is almost zero, it was recently reported that its vertical thermal expansion coefficient (CTE) was approximately one order of magnitude larger than the lateral CTE. Though the birefringence is not an absolute predictor of anisotropic behavior, the discrepancy in both the CTEs was so remarkable that it was essential to investigate whether the anisotropy was intrinsic property or not. If the effect of Poisson's ratio is considered in the calculation of the vertical CTE and when elastic modulus measured by surface acoustic wave spectroscopy is used in the assessment of the lateral CTE, both the CTEs are coincident with each other. Therefore, it can be concluded that the discrepancy in the CTEs can be attributed to a higher in‐plane polymer chain orientation but it can also arise from the misleadingly assumed modulus and Poisson's ratio. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3109–3120, 2006     

溶胶-凝胶VO2薄膜转换特性研究

利用溶胶凝胶法在SiO2Si衬底上沉积高取向的V2O5薄膜,在压强低于2Pa,温度高于400℃的条件下,对V2O5薄膜进行真空烘烤,获得了电阻率变化3个数量级以上、弛豫宽度为62℃的VO2多晶薄膜.以X射线衍射(XRD)、扫描电子显微镜(SEM)图和电阻率转换特性等实验结果为依据,详细分析了溶胶凝胶薄膜在真空烘烤时从V2O5向VO2的转化,它经历了从VnO2n+1(n=2,3,4,6)到VO2的过程.实验证明,根据选择合适的成膜热处理条件和真空烘烤条件是实现溶胶凝胶V2O5结构向VO2结构成功转换的关键 关键词： 溶胶-凝胶法 氧化钒薄膜 VO2膜转换特性     

Effects of nickel on the crystallization of Zr70Cu20Ni10 amorphous alloy

Differential scanning calorimetry (DSC) and x-ray diffraction (XRD) are employed to investigate the effects of nickel on the crystallization of the amorphous Zr₇₀Cu₂₀Ni₁₀ alloy. We have found that the crystallization process of the amorphous Zr₇₀Cu₂₀Ni₁₀ alloy is strongly influenced by the addition of nickel. Addition of 10 at% Ni to the Zr₇₀Cu₃₀ amorphous alloy makes the crystallization process proceed from a single-stage mode to a double-stage mode. The activation energy for crystallization of the amorphous Zr₇₀Cu₂₀Ni₁₀ alloy is calculated to be about 388kJ·mol^-1 on the basis of the Kissinger equation. The effects of nickel on the crystallization of the amorphous Zr₇₀Cu₂₀Ni₁₀ alloy are discussed in terms of the genetics of metals.     

Photo-Absorption and photochemical decomposition of copper and alkaline-earth ß-diketonates as source gases of high-Tc superconducting films

For low-temperature deposition of oxide films relating to Bi-Sr-Ca-Cu-O superconductors, photo-absorption and -decomposition properties were examined with respect to copper and alkaline-earth ß-diketonates. It was confirmed that all ß-diketonates examined were promising as source materials for photochemical vapour deposition (photo-CVD) using a low-pressure mercury lamp, in view of their large light absorption coefficients at wavelength 254 nm. The light irradiation was effective for the formation of highly crystalline oxide films at temperatures below 600 °C. By combining two sources, Ca₂CuO₃ and SrCuO₂ films were prepared. Photo-CVD of c-axis oriented Bi₂Sr₂CuO_x film was achieved by the irradiation of ternary sources of Bi(C₆H₅)₃ and strontium and copper ß-diketonates at 500 °C.     

高温超导薄膜微波非线性研究的进展

文章介绍了高温超导薄膜微波非线性的主要特征，阐述了高温超导薄膜微波非线性产生的原因和相关的研究现状，指出了高温超导薄膜非线性研究中遇到的困难和尚未解决的问题．     

Polarization inscription in ferroelectric (111) PZT and (100) SBT films

Ferroelectric thin films form an equilibrium domain structure compatible with their respective crystallographic symmetry. In tetragonal (111) PZT, 90° domains prevail; in (pseudo-tetragonal) (100) SBT both 90° and 180° domains are present. The size of 90° domains has been measured for e.g., PZT as slabs of 15 nm width. Domain size is a result of stress minimization in the film during the paraelectric (PE) → ferroelectric (FE) transition. A precise and regular domain pattern for (111) PZT and (100) SBT films has been investigated in detail by TMSFM. Single domains can be addressed mechanically with the tip of an AFM. Such single domain switching corresponds to a data storage density of 200 Gbit/inch². Applications of ferroelectric and high- paraelectric materials for e.g., non-volatile data storage replacing DRAM devices or as sensors in infrared cameras are increasingly becoming popular.