Novel Protonic Conductive Silicates Produced by the Sol-Gel Method

ABSTRACT

Materials which display ionic conductivity were produced by the sol-gel and microemulsion-gel methods. The charging and discharging characteristics were investigated and it was found that a single ionic species was responsible for the conduction, the ionic species being residual protons from the initial component mixture. The complex impedence of various samples was measured and the ionic conductivities ranged in value from 9 × 10^?8 to 1 × 10^?5 ohm^?1 cm^?1. An Arrhemius plot for a microemulsion-gel revealed that the energy of activation was 0.15 eV.     

Zur Methodik der Autoradiographie im Elektronenmikroskop

Die elektronenmikroskopische Autoradiographie erlaubt unter Ausmutzung des hohen Auflösungsvermögens des Elektronenmikroskops eine exakte Lokalisierung radioaktiver Verbindungen in Präparaten. Voraussetzung dafür ist die Herstellung einer Einkornschicht des Silberhalogenids aus einer vorgegebenen Filmemulsion. Diese Einkornschicht mit möglichst gleichmäßiger Silberhalogenidverteilung muß dann auf das radioaktive Objekt aufgebracht werden. Nach einer Übersicht über die Versuchsmethode werden Untersuchungen zur Präparation von Silberhalogenid-Einkornschichten aus den Emulsionen ORWO K 2, K 5, K 6, Ilford L 4 und Gevaert Nuc 7.15 für die elektronenmikroskopische Autoradiographie dargestellt.     

Polycrystalline silicon films prepared by metal-induced crystallisation using pre- and post-deposited aluminium on amorphous silicon

We report on the successful fabrication of polycrystalline silicon films by aluminium-induced crystallisation (AIC) of Radio frequency (rf) plasma-enhanced chemical vapour deposited (PECVD) a-Si films. The effects of annealing at different temperatures (300 and 400°C), below the eutectic temperature of the Si–Al binary system, on the crystallisation process have been studied. This work emphasises the important role of the position of the Al layer with respect to the Si layer on the crystallisation process. The properties of the crystallised films were characterised using X-ray diffraction, Raman spectroscopy, ellipsometry, field-emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). With an increase in the annealing temperature, it was found that the degree of crystallisation of annealed a-Si/Al and Al/a-Si films increased. The results showed that the arrangement where the Al was on top of the a-Si had a more prominent effect on crystallisation enhancement than when Al was below the a-Si. The interfacial layer between the Al and a-Si film is crucial because it influences the layer-exchange process during annealing. The oxide layer formed between the Al and the a-Si layers greatly retards the crystallisation process in the case of the Al/Si arrangement. Our investigations suggest that polycrystalline Si films formed by AIC can be used as a seed layer in solar cell fabrication.     

GaAs薄膜的有效量子限制长度及其极化子特性

本文用分数维方法研究Al_xGa_1-xAs衬底上GaAs薄膜中的极化子特性, 提出了确定GaAs薄膜的有效量子限制长度的一个新方法, 解决了原来方法中在衬底势垒处有效量子限制长度发散的困难, 得到了Al_xGa_1-xAs衬底上GaAs薄膜中的极化子的维数和结合能. 关键词： 分数维方法 极化子 GaAs薄膜     

表面力仪的改进及超薄膜流变特性的实验研究

在对原表面力仪进行较大改进的基础上 ,以 5 0 0 SN基础油和十六烷为研究对象 ,进行了超薄膜流变特性的实验研究 .结果表明 :在超薄膜润滑条件下 ,5 0 0 SN和十六烷均表现出明显的非牛顿剪切响应 ,即剪切稀释现象 ;摩擦力幅值随剪切速度的增大急剧上升到最大值 ,然后下降至某一固定值附近并产生波动 ;剪切挤压下的临界膜厚小于静态挤压的临界膜厚 ,剪切运动对吸附层有序结构产生破坏作用     

Pico-second photoelectric characteristic in manganite oxide La0.67Ca0.33MnO3 films

Ultrafast photoelectric characteristic has been observed in La_0.67Ca_0.33MnO₃ films on tilted SrTiO₃ substrates. A pico-second (ps) open-circuit photovoltage of the perovskite manganese oxide films has been obtained when the films were irradiated by a 1.064μm laser pulse of 25 ps duration. The rise time and full width at half-maximum of the photovoltage pulse are ～300 ps and ～700 ps, respectively. The photovoltaic sensitivity was as large as ～500 mV/mJ.     

沟道层厚度对室温制备的In2O3薄膜晶体管器件性能的影响

在室温下采用直流磁控溅射以SiO₂/Si为衬底制备了不同沟道层厚度的底栅式In₂O₃薄膜晶体管,讨论了沟道层厚度对底栅In₂O₃薄膜晶体管的电学性能的影响。实验结果表明:器件的特性与沟道层厚度有关,最优沟道层厚度的In₂O₃薄膜晶体管为增强型,其阈值电压为2.5 V,开关电流比约为10⁶,场效应迁移率为6.2 cm²·V^-1·s^-1。     

Ag/AAO纳米有序阵列复合结构等效光学参量的确定

引入厚度偏差Δd, 修正了薄膜透射率表达式.基于Ag/AAO纳米有序阵列复合结构实验透射光谱(500—2700nm)的两条极值包络线, 定义了一个优化函数, 结合最优化数值算法尝试确定具有较强吸收的Ag/AAO纳米有序阵列复合结构的等效光学参量. 由此计算了该结构的等效折射率n、等效消光系数k、平均等效厚度d以及厚度偏差Δd. 该方法对Ag/AAO纳米复合结构平均等效厚度的相对计算误差仅为0.3%, 与实测厚度基本一致, 且Ag/AAO纳米复合结构的模拟透射谱与实验透射光谱在500—2700nm波段范围内相符. 这表明该计算方法可有效确定Ag/AAO纳米复合结构的等效光学参量, 并与实验结果是自洽的. 关键词： 薄膜光学 光学参量 纳米复合结构 最优化算法     

椭圆偏振技术研究VHF-PECVD高速沉积微晶硅薄膜的异常标度行为

采用VHF-PECVD技术高速沉积了不同生长阶段的微晶硅薄膜,通过椭圆偏振技术研究了生长过程中微晶硅薄膜表面粗糙度的演化.实验结果表明,沉积气压P_g=300 Pa时,β=0.81,其超出标度理论中β最大值为0.5范围,出现异常标度行为.这表明微晶硅薄膜高速生长中还存在其他粗糙化增加的因素,此粗糙化增加的因素与阴影作用有关. 关键词： 微晶硅薄膜 椭偏光谱法 生长机制 表面粗糙度     

用于红外激光防护的高开关率VO2薄膜

采用反应离子束溅射和后退火处理技术在石英玻璃基底上制备了具有纳米粒子的二氧化钒(VO₂)薄膜. 该薄膜具有半导体-金属相变特性,在3 μm处的开关率达到76.6%。 热致相变实验结果给出了准确的最佳退火温度为465 ℃. 仿真、热致相变和光致相变实验都显示VO₂薄膜在红外波段具有很高的光学开关特性. 光电池防护实验结果显示VO₂薄膜将硅光电池的抗干扰能力提升了2.6倍, 证明了VO₂在激光防护中的适用性. 采用连续可调节系统研究得到VO₂在室温条件下的相变阈值功率密度为4.35 W/cm², 损伤阈值功率密度为404 W/cm²。 低相变阈值和高损伤阈值都进一步证明VO₂薄膜适用于激光防护系统。本实验制备的VO₂薄膜在光开关、光电存储器、智能窗等方面也具有广泛的应用价值.