Cl-对镁-铝合金β相模型合金表面膜稳定性的影响

采用电化学阻抗测试技术(EIS)、Mott-Schottky方法对β相模型合金在Cl-溶液环境中形成的表面膜的稳定性和半导体特性进行研究.结果表明,Cl-浓度的增加,使β相表面膜形成和活化溶解的趋势均加剧,即表面膜的稳定性变差.原因在于Cl-浓度较低时,β相表面膜的半导体类型为P型,P型半导体膜是一种阳离子导体膜,Cl-很难通过迁移扩散的方式穿过表面膜.随着Cl-浓度的增大,β相表面膜的半导体类型转变为N型,N型半导体膜便于Cl-穿越膜层到达膜层底部,继续腐蚀金属并使表面膜发生破裂.     

Growth behavior of polycrystalline silicon thin films deposited by RTCVD on quartz substrates

Polycrystalline silicon (poly-Si) thin films were prepared on quartz substrates by rapid thermal chemical vapor deposition (RTCVD) system, and their structures were studied by XRD, SEM and TEM, respectively. XRD spectra exhibit a single strong (220) diffraction peak, which indicates that the poly-Si films are preferentially <110> oriented. Plane-view SEM images show that the surface of the poly-Si films is composed of large numbers of polygonal pyramid grains with different sizes, and cross-section SEM images further indicate that they are columnar grains with growth direction perpendicular to substrate surface. TEM observation results demonstrate that there are a lot of twin crystals including one-order, two-order and high-order (≥3) twin crystals in the poly-Si films. The above experimental results can not be elucidated by the conventional opinion on growth behavior of poly-Si films prepared by atmosphere pressure chemical vapor deposition (APCVD), but can be explained by the Ino’s multiply twinned particles (MTPs) model found in the face centered cubic metal films. According to the above experimental results and Ino’s model, we tend to think that nucleation and grain growth of poly-Si films deposited by RTCVD on quartz substrates are based on the formation of MTPs, and then these MTPs form the continuous films in an island growth mode.     

Effect of Mg content on the structural and optical properties of Mg<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>Zn<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript>O alloys

Mgx Zn1–x O thin films with x = 0, 0.11, 0.28, 0.44, 0.51, and 0.65 were grown by plasma-assisted molecular beam epitaxy on (0001) sapphire substrates. X-ray diffraction measurement reveals that phase separation of the Mgx Zn1–x O films occurred at x =0.44 and 0.51. Optical absorption spectra show that the absorption edges of the films shift to high-energy side with increasing Mg contents. In resonant Raman spectra, multiple-order Raman peaks originating from ZnO-like longitudinal optical phonons were obser...     

聚合物覆膜对长周期光栅灵敏度的调制

利用静电自组装技术在长周期光栅表面组装了聚丙烯胺盐酸盐(PAH)/聚苯乙烯磺酸钠(PSS)薄膜,并探索了覆膜的长周期光栅对异丙醇、乙醇、甲醇、水、空气的响应性能。实验表明,聚合物薄膜的厚度或组装层数对长周期光栅的灵敏性产生了调制,使长周期光栅对折射率呈如下的敏感规律:随着组装层数的增加,长周期光栅对折射率的敏感性逐渐从高折射率向低折射率转移;并且长周期光栅对折射率相邻的介质有一个最佳敏感区。这对开发高灵敏性和高选择性的长周期光栅生化传感器提供了很好的依据。     

Photo-induced optical changes in GexAs40Se60-x thin films

Ge-As-Se chalcogenide thin films show a wide range of photosensitivity, which is utilized for the fabrication of micro-optical elements for integrated optics. The photosensitivity of GexAs40Se60?x(x=0,15) chalcogenide thin films for UV light was presented. For that purpose, the bulk samples of GexAs40Se60?x(x=0,15) chalcogenide glasses were prepared using conventional melt quenching technique, and thin films were prepared using thermal evaporation technique. These thin films were exposed to UV light for two hours. Amorphous natures of bulk samples and thin films were verified by XRD and chemical compositions were verified by EDX measurements. The thicknesses of the thin films were measured using a thickness profilometer. Linear optical analysis of these thin films was done using transmission spectra in wavelength range of 300?900 nm. Optical bandgap was determined by first peak of transmission derivative as well as extrapol ation of Tauc’s plot. R2 analysis was done using R software to ensure that the material is indirect bandgap material. It is observed that two hours UV exposure causes photo-darkening along with photo-expansion in As40Se60 thin films, while photo-bleach ing and photo-densification for Ge15As40Se45 thin films. However, the amounts of photo-induced optical changes for Ge15As40Se45 thin films are smaller than those for As40Se60 thin films. The changes in optical absorption, bandgap and thickness are understood base d on the bonding rearrangement caused by UV exposure.     

磁性材料的交换偏置效应浅谈

交换偏置效应的根源在于铁磁反铁磁界面处交换各向异性能的存在,该效应导致磁滞回线偏置,已应用于信息存储技术及永磁体磁性增强。文章介绍了磁性材料的交换偏置研究进展情况、交换偏置效应的应用、交换偏置计算模型、交换偏置材料制备手段等方面,展望了在新理论、新实验技术的推动下交换偏置研究的前景。针对òscar Iglesias等提出的计算交换各向异性能的公式,提出了通过自洽场理论来得到更为准确的结果。     

恒电流电沉积ZnO薄膜及其光电性能研究

采用恒电流电沉积的方法,在ITO导电玻璃上制备ZnO薄膜.通过X射线衍射仪、扫描电子显微镜等手段,对制备出的ZnO薄膜进行表征,并研究了溶液的pH值对薄膜的光学性质的影响.结果表明,电流密度为0.175mA·cm-2、pH为4.7时,制备出的ZnO薄膜具有纤锌矿结构,薄膜表面较均匀、致密,具有很好的附着力,在可见和近红外波段透过率约为80%,禁带宽度为3.37eV.光电流测试表明薄膜的导电类型为n型.     

用离子化技术制备C-BN薄膜

立方晶系的氮化硼(C-BN)具有极好的硬度、绝缘性,近年来受到国内外的注目。本文介绍在10~(-1)Pa的氮气氛中,用电子束蒸发硼,再进行离子化,制得氮化硼薄膜。经电子显微镜衍射图分析及与块状材料相比,其晶格距离极为一致,本文还分析了薄膜形成过程中基板温度、真空度等的影响。     

平面厚膜SnO2乙醇敏感器件的研制

分绍一种利用厚膜工艺制作的ＳｎＯ２乙醇敏感器件。重点介绍实验方法；分析了该器件的灵敏度、选择性的特点。证实该方法可制得较高电参数一致的，高灵敏度、选择性的乙醇敏感器件。     

高TCR薄膜温度传感器的研究

本文作者利用镍金属的优良特性,通过特定的工艺处理和控制,研制出了性能价格比高的薄膜温度传感器,其使用温区为-50～250℃;TCR 可达5900(10~(-6) /℃);线性度为±2. 13%;响应时间≤0. 2秒;电阻值为100～150Ω并可调整。