Optical and electrical properties of ITO film on flexible fluorphlogopite substrate

Indium Tin Oxide (ITO) films were prepared, at room temperature, on a fluorphlogopite substrate using magnetron sputtering technology. At various temperatures of 500 °C, 600 °C, 700 °C, 800 °C, and 900 °C, the samples were (had) annealed for 2 h (a 2-h duration). The results showed improvement in the crystalline performance of ITO film at selected annealing temperatures, with a significant reduction in resistivity at 800 °C. The lowest resistivity is 4.08 × 10^?4 Ω-cm, which is nearly an order of magnitude lower than the unannealed sample. All samples have an average light transmittance above 85% in the visible light range (400–800 nm), and with increasing annealing temperature, the average light transmittance tends to decrease. Besides, at the sensitive wavelength of 550 nm, the light transmittance is as high as 93.74%. The sheet resistance testing of the sample was through the number of bending times, which revealed that with the increase of the number of bending, the sheet resistance increases. However, after 1200 bending times, the change rate of the sheet resistance remains below 5%. Thus, the ITO film prepared on the flexible fluorphlogopite substrate revealed excellent optical and electrical properties, good flexibility, and improved stability after high-temperature annealing, which guarantees successful application in flexible electronic devices.     

Synthesis,characterization and charge transport properties of Pr–Ni Co-doped SrFe2O4 spinel for high frequency devices applications

Ferrites are materials of interest due to their broad applications in high technological devices and a lot of research has been focused to synthesize new ferrites. In this regard, an effort has been devoted to synthesize spinel Pr–Ni co-substituted strontium ferrites with a nominal formula of Sr_1-xPr_xFe_2-yNi_yO₄ (0.0 ≤ x ≤ 0.1, 0.0 ≤ y ≤ 1.0). The cubic structure of pure and Pr–Ni co-substituted strontium ferrite samples calcinated at 1073 K for 3 h has been confirmed through X-ray diffraction (XRD). Average sizes of crystallites (18–25 nm) have been estimated from XRD analysis and nanometer particle sizes of synthesized ferrites have been further verified by scanning electron microscopy (SEM). SEM results have also shown that particles are mostly agglomerated and all the samples possess porosity. It has been observed that at 298 K, the values of resistivity (ρ) increase, while that of AC conductivity, dielectric loss, and dielectric constants decrease with increasing amounts of Pr³⁺ and Ni²⁺ ions. The values of dielectric parameters initially decrease with frequency and later become constant and can be explained on the basis of dielectric polarization. Electrochemical impedance spectroscopy (EIS) studies show that the charge transport phenomenon in ferrite materials is mainly controlled via grain boundaries. Overall, synthesized ferrite materials own enhanced resistivity values in the range of 1.38 × 10⁹–1.94 × 10⁹ Ω cm and minimum dielectric losses, which makes them suitable candidates for high frequency devices applications.     

High resistivity measurement of SiC wafers using different techniques

To establish fast, nondestructive, and inexpensive methods for resistivity measurements of SiC wafers, different resistivity-measurement techniques were tested for characterization of semi-insulating SiC wafers, namely, the four-point probe method with removable graphite contacts, the van der Pauw method with annealed metal and diffused contacts, the current-voltage (I-V) technique, and the contactless resistivity-measurement method. Comparison of different techniques is presented. The resistivity values of the semi-insulating SiC wafer measured using different techniques agree fairly well. As a result, application of removable graphite contacts is proposed for fast and nondestructive resistivity measurement of SiC wafers using the four-point probe method. High-temperature van der Pauw and room-temperature Hall characterization for the tested semi-insulating SiC wafer was also obtained and reported in this work.     

基体温度对磁控溅射沉积ZAO薄膜性能的影响

利用中频交流磁控溅射方法 ,采用氧化锌铝陶瓷靶材 [w(ZnO) =98%、w(Al2 O3 ) =2 % ]制备了ZAO(ZnO∶Al)薄膜 ,观察了基体温度对ZAO薄膜的晶体结构、电学和光学性能的影响 ,采用X射线衍射仪对薄膜的结构进行了分析 ,采用光学分度计和电阻测试仪测量了薄膜的光学、电学特性 ,采用霍尔测试仪测量了薄膜的载流子浓度和霍尔迁移率。结果表明 :沉积薄膜时的基体温度对薄膜的结构、结晶状况、可见光透射率以及导电性有较大的影响。当基体温度为 2 5 0℃ ,Ar分压为 0 8Pa时 ,薄膜的最低电阻率为 4 6× 10 -4Ω·cm ,方块电阻为 35Ω时 ,可见光 (λ =5 5 0nm)透射率高达 92 0 %。     

激电法找油的原理及应用

激电法是非地震物探手段中的一种，由于油气在向上渗透的过程中会与地层发生一系列的生物。化学反应而形成次生黄铁矿，激电法正是通过发现油气藏上方形成的次生黄铁矿晕来寻找油气的一种间接找油方法。通过详细介绍激电法寻找油气的基本原理。仪器设备等，从实践角度论述了激电法在油田勘探开发中的应用范围及其特点，最后通过兴例说明了其良好的应用效果。     

测井岩性类比解释法及应用

利用理想的地质体积模型和电阻率测井的供电电流流过模型的导电机理,推导出一种不需要含水饱和度参数即能定量计算含水饱和度的方法,即岩性类比解释法。经过初步实践,该方法应用于砂泥岩地层的测井分析,效果良好。     

利用测井资料评价储集层性质的探讨

根据对储集层之简化导电模型的理论分析,提出了一个由电阻率、孔隙度信息表示的、反映储层性质的“孔隙结构参数S”。实际应用表明,S参数在评价储集层性质、计算储层渗透率等方面具有一定的使用价值。     

接地降阻剂机理及用量研究

本文介绍我们对降阻剂降低接地电阻的机理所作的试验研究结果。这个问题目前尚有争议,有人认为存在着很大的所谓浸润层,亦有人持怀疑态度。我们的试验表明,在埋设降阻剂时确实存在着降阻剂导电溶液向土壤中渗透的一定区间。经过理论分析计算,确定了渗透层的厚度和渗透层的平均土壤电阻率。渗透层并不大,约几公分到十几公分,它可使降阻率提高约20～30％,并有良好的均压作用。仅少数的试验结果已可看出,降阻率的提高对降咀剂用量的关系具有饱和特性。     

Temperature-dependent resistivity from phonons in cuprate superconductors

The temperature dependence of the resistivity of the cuprate superconductors arising from phonon scattering is considered within standard Bloch-Gruneisen theory allowing for several different shapes of transport spectral functions _tr ² F(). In contrast to often made comments that linear resistivity is not characteristic of electron-phonon scattering, it is shown rather that it is more difficult to get muchnonlinearity from this theory except below 50–100 K, and in this low-T regime better solutions to the Boltzmann equation might be required. The reasons for the linear behavior are clarified, and the variations to be expected from possible coupling functions are explored. Possible origins of the nonlinear resistivity seen in YBa₂Cu₄O₈ and recently in YBa₂Cu₃O₇ are suggested, and effects not included specifically in these calculations are discussed. It is also pointed out that phonon contributions to the energy () dependence of quasiparticles, which is a closely related consequence of electron-phonon coupling, will differ significantly from the simple ² Fermi liquid behavior that is commonly assumed.     

Inverse resistivity problem: Geoelectric uncertainty principle and numerical reconstruction method

Mathematical model of vertical electrical sounding by using resistivity method is studied. The model leads to an inverse problem of determination of the unknown leading coefficient (conductivity) of the elliptic equation in R²$R^2$ in a slab. The direct problem is obtained in the form of mixed BVP in axisymmetric cylindrical coordinates. The additional (available measured) data is given on the upper boundary of the slab, in the form of tangential derivative. Due to ill-conditionedness of the considered inverse problem the logarithmic transformation is applied to the unknown coefficient and the inverse problem is studied as a minimization problem for the cost functional, with respect to the reflection coefficient. The Conjugate Gradient method (CGM) is applied for the numerical solution of this problem. Computational experiments were performed with noise free and random noisy data.