ZAO透明导电薄膜的制备及性质

ZAO（ZnO：Al）透明导电薄膜是一种具有高的载离子浓度和宽禁带的半导体氧化物，电学和光学性能优异。极具应用前景。本文介绍了ZAO薄膜的制备现状、特性、磁控溅射参数对其电学和光学性质的影响以及今后研究的方向。     

氢气热处理制备大块导电石墨烯薄膜及表征

通过真空抽滤水中分散良好的氧化石墨烯获得薄膜,并在600℃氢气气氛中保温2h还原即可获得含氧量极低的大片导电石墨烯(GE)薄膜。以X射线衍射(XRD)、红外分析(FT-IR)、拉曼光谱仪(Ramanspectroscopy)研究氢气气氛热处理前后薄膜的物相、官能团组成和分子结构;采用SEM观察石墨烯薄膜的表面形貌;采用四探针测试仪对氢气气氛热处理前后薄膜的电学行为进行了对比考察。实验结果表明,氢气气氛热处理氧化石墨烯可以获得含氧量极低且导电性能优良的石墨烯;96mL浓度为0.0937mg/mL的氧化石墨烯溶液抽滤膜经氢气处理后获得的石墨烯薄膜方阻达到11.3Ω/□,薄膜电阻率为0.6Ω.cm。     

两步还原法制备导电石墨烯薄膜

通过两步还原法制备了导电石墨烯薄膜。采用XPS、Raman等表征了薄膜的结构;采用四探针电阻仪表征了薄膜电学性能。结果表明:用两步法制备的石墨烯薄膜具有更高的还原程度,其碳和氧的原子比达8.9∶1;薄膜的方块电阻为0.42kΩ/□,而同等厚度的一次还原薄膜的方块电阻为5.57kΩ/□。     

三氧化二铟基透明导电薄膜光、电特性的研究

本文是一篇综述性报告，根据近年来的有关报道，结合作者的实验结果，对IO、ITO透明导电薄膜的研究情况和实验方法作了简要的评述，重点讨论了其电学性能和光学性能及影响它们的主要因素，分析了透过率峰位移随膜厚的变化关系，等离子体共振吸收峰与载流子浓度的依赖关系及紫外范围吸收限的位移与跃迁能隙的关系等。为进一步深入研究和制备优质透明导电薄膜提供参考。     

化学法制备掺铝氧化锌透明导电薄膜的研究进展

综述了掺铝氧化锌(ZAO)透明导薄膜的化学法制备技术、及应用前景,重点介绍了溶胶-凝胶法制备ZAO薄膜的热处理条件、溶胶浓度、陈化时间、加水量以及稳定剂种类和用量等方面对薄膜结构和性能的影响.     

湿化学工艺SrNbxTi1-xO3导电薄膜的制备及性能

采用湿化学工艺在硅衬底上成功地制备了结构致密、均匀且无龟裂的SrNbxTi1-xO3薄膜.金属盐的冰醋酸溶液经回流再加入乙酸酐除去无机阴离子和结晶水,形成的金属醋酸盐与适当的络合剂形成的多配体络合物经部分水解生成的羟基化合物M(OH)n-x(L)x(L=C4H6O6或AcAc,M=Sr或Ti或Nb)经羟基聚合形成SrNbxTi1-xO3簇状溶胶.丙三醇抑制了羟基金属过度聚合,甲基纤维素(MCL)使SrNbxTi1-xO溶胶具有网状结构.SrNb0.1Ti0.9O3(SNTO)凝胶薄膜经过650～750℃/30min退火形成假立方钙钛矿结构.应用XRD、SEM和TEM对薄膜结构和形貌进行表征.室温下SNTO薄膜的电阻率为54μΩ·cm,而在160K到室温之间薄膜电阻率随温度的变化遵从p=p0 AT2.分析结果表明:Nb5 离子的施主掺杂改变了禁带宽度,实现了SrTiO3的n-型半导体化.SNTO(100)/Pt/Ti/SiO2/Si衬底上的Pb(Zr0.52Ti0.48)O3(PZT)薄膜的择优取向明显,较之于Pt/Ti/SiO2/Si衬底上的PZT薄膜有良好的铁电性,其剩余极化强度也比PZT/Pt(111)/Ti/SiO2/Si的大.     

氧化钒-氧化石墨烯复合薄膜的制备及其光电特性

基于溶胶凝胶法,采用旋涂和喷涂相结合的工艺,制备了氧化钒（VO_x,1≤x≤2.5）-氧化石墨烯（GO）复合薄膜。利用SEM、XRD、椭偏仪、紫外可见分光光度计、FTIR及高阻仪对所制薄膜的形貌、晶相、光学及电学性能进行了系统的表征测试。结果表明,加入GO之后,VO_x-GO复合薄膜的电阻率由108.78 Ω·cm下降至68.64 Ω·cm,而薄膜的电阻温度系数（TCR）则由-1.98% K^-1提高至-2.60% K^-1。此外,VO_x-GO复合薄膜还具有更高的光吸收率和工作稳定性。说明GO的加入增强了VO_x薄膜作为非制冷红外探测器热敏材料的综合性能。本研究为探索基于VO_x的新型红外热敏材料提供了参考,同时也对非制冷红外探测器的发展有促进作用。     

氧化钒薄膜制备与特性研究

用磁控反应溅射法制备出具有红外敏感特性的氧化钒薄膜,进行了薄膜光电特性的测试.通过AFM和XRD对薄膜的结构和特性进行分析研究,并给出了沉积参数对薄膜性能的影响.     

水溶性石墨烯及其高导电率薄膜的制备与表征

石墨烯表面不含含氧基团, 这导致石墨烯在水中很难分散. 制备具有水溶性的石墨烯是一个研究焦点. 本研究采用氧化石墨低温真空膨胀的方法, 通过调控氧化石墨烯的含氧基团数目, 制备具有水溶解性的石墨烯材料. AFM测试表明所制备的水溶性石墨烯的最小片层厚度约为1.7 nm, 尺寸为1.0 μm. 分散实验结果表明; 所制备的石墨烯在不添加任何表面活性剂的中性水溶液情况下可以稳定分散, 其浓度为0.07 mg/mL; 此外, 电性能测试表明: 石墨烯薄膜材料的导电率可高达1000 S/m, 比通过非共价键石墨烯制备的薄膜导电率要高.     

有序石墨烯导电炭薄膜的制备

采用Hummers法合成氧化石墨,在水中超声分散获得氧化石墨烯水溶胶,通过微滤法使氧化石墨烯片定向流动组装,制得氧化石墨烯薄膜.再通过化学还原和热处理使所制氧化石墨烯薄膜脱氧重石墨化,保持其形貌时可控制其导电性,制得电导率为184.8S/cm的石墨烯导电炭膜.     

溶胶-凝胶法制备的ITO薄膜电学及光学性能的研究

以无机盐为出发原料．采用溶胶-凝胶法制备了氧化铟锡(ITO)透明导电薄膜。进一步研究了热处理气氛、温度、Sn掺杂量时In2O3薄膜电学及光学性能的影响。分别在氮气、真空和空气3种环境下对薄膜进行热处理．结果表明真空热处理后薄膜的导电性最好。研究了薄膜方块电阻随锡掺杂量的变化．发现薄膜的方阻随掺锡量的增加先减小后增加,并在掺杂量为7mol％左右时达到最低;另外探讨了热处理温度对薄膜光电性能的影响．结果发现薄膜方块电阻随热处理温度的升高而减小．且热处理温度高于700℃后变化不显著,薄膜在可见光区平均透过率随热处理温度升高呈上升趋势。本研究所制得的薄膜可见光区(400-800nm)平均透过率可达85％、方阻约为66Ω。     

Preparation and study of thickness dependent electrical characteristics of zinc sulfide thin films

Zinc sulfide thin films have been deposited onto glass substrates by chemical bath deposition. The various deposition parameters such as volume of sulfide ion source, pH of bath, deposition time, temperature etc are optimized. Thin films of ZnS with different thicknesses of 76–332 nm were prepared by changing the deposition time from 6–20 h at 30° C temperature. The effect of film thickness on structural and electrical properties was studied. The electrical resistivity was decreased from 1.83 × 10⁵ Ω-cm to 0.363 × 10⁵ Ω-cm as film thickness decreased from 332 nm to 76 nm. The structural and activation energy studies support this decrease in the resistivity due to improvement in crystallinity of the films which would increase the charge carrier mobility and decrease in defect levels with increase in the thickness.     

脉冲激光沉积法制备Pt薄膜的研究

采用脉冲激光沉积技术在(0001)取向的蓝宝石基片上外延生长了Pt单晶薄膜,研究了沉积温度和激光能量对Pt薄膜的晶体结构,表面形貌及电学性能的影响规律.X射线衍射(XRD)分析结果表明,在沉积温度650℃、激光脉冲频率1Hz和激光能量280mJ的条件下,制备得到的Pt(111)单晶薄膜,其(111)面ω摇摆曲线半高宽(FWHM)仅为0.068°.原子力显微镜(AFM)分析表明外延的Pt薄膜表面具有原子级平整度,其表面均方根粗糙度(RMS)约为1.776nm.四探针电阻测试结果显示薄膜方阻为1/962Ω/□,满足铁电薄膜的制备工艺对Pt底电极的要求.     

Preparation of high dielectric constant thin films of CaCu3Ti4O12 by sol-gel

Preparation of sol-gel derived CaCu₃Ti₄O₁₂ (CCTO) thin films using two different sols and their characterization including their dielectric response are reported. The properties of CCTO films depend heavily on solvents used to prepare the sols. Dielectric constant as high as ∼900 at 100 kHz could be obtained when acetic acid was used to prepare the sol; in contrast, use of hexanoic acid in the sol yielded films with a much lower dielectric constant. The variation in grain and grain boundary conductivities with temperature has been measured. Activation energies of 0.08 eV and 0.68 eV have been found for grain and grain boundary conduction, respectively.     

Thermally stable, highly conductive, and transparent Ga-doped ZnO thin films

Highly conductive and transparent films of Ga-doped ZnO (GZO) have been prepared by pulsed laser deposition using a ZnO target with Ga₂O₃ dopant of 3 wt.% in content added. Films with resistivity as low as 3.3 × 10^− 4 Ω cm and transmittance above 80% at the wavelength between 400 and 800 nm can be produced on glass substrate at room temperature. It is shown that a stable resistivity for use in oxidation ambient at high temperature can be attained for the films. The electrical and optical properties, as well as the thermal stability of resistivity, of GZO films were comparable to those of undoped ZnO films.     

Design of ZnO/Ag/ZnO multilayer transparent conductive films

We have studied the properties of ZnO/Ag/ZnO multilayers prepared on glass substrates by simultaneous RF magnetron sputtering of ZnO and dc magnetron sputtering of Ag. The electrical and optical performance of Ag and ZnO single layer films was also investigated. Different optimization procedures were used for good transparent conductive film. Several analytical tools such as spectrophotometer, scanning electron microscope (SEM), four-point probes were used to explore the causes of the changes in electrical and optical properties. Low sheet resistance of 3 Ω/sq. and transmittance over 90% at 580 nm was achieved. The results of optimization condition of both oxide layers and metallic Ag layers were illustrated.     

Electrical properties of thermally evaporated tellurium thin films

Results of dielectric and conduction properties of vacuum evaporated tellurium (Te) thin film capacitors (Al-Te-Al) have been reported in the frequency range 1–100 kHz at various temperatures (303–423 K). Loss factor (tanδ) which shows a maximum with frequency increases with rise of temperature and tanδ _max shift towards high frequency region. The large values of capacitance and dielectric constant (ɛ′) in the low frequency region indicate the possibility of an interfacial polarization mechanism.I-V characteristics show ohmic, space charge limited (SCLC) and thermionic emission conduction mechanisms to operate at low, intermediate and high voltages respectively. Various transport parameters have been calculated. It has been observed that the Schottky type of conduction is predominant in the high field region and the Schottky barrier height has been determined. The Hall coefficient, Hall mobility and carrier concentration are also discussed.     

Electrical,electromechanical and thermal properties of thin tellurium films

Thin films of tellurium of wide range of thicknesses have been deposited by vacuum evaporation and their electrical properties such as electrical resistivity and temperature coefficient of resistance have been measured. The suitability of these films for possible use as strain gauges has been studied and their strain resistivity behaviour is presented. The thermal conductivity of these films have been determined and these results are presented alongwith. An interesting phenomenon has been noticed. In all these effects an extraordinary behaviour is observed at a specific thickness. This smears out with an increase in the thickness of the film. These effects are explained in terms of size effects in thin films.     

Preparation and characterization of flash-evaporated CuInSe2 thin films

Thin films of CuInSe₂ have been evaporated onto glass substrates by flash evaporation. The as-deposited films are amorphous and annealing in selenium atmosphere produces polycrystalline films. The films were characterized bytem and x-ray diffraction techniques. The optical absorption of the films shows three energy gaps of 1·03, 1·07 and 1·22 eV. The crystal field and spin-orbit splitting are thus found to be 0·04 eV and 0·16 eV respectively. The percentaged-character of the valence band states is ∼35%. The Arrhenius plot of electrical conductivity of films showed impurity ionization ofE _A = 75 meV.     

Preparation and conductive properties of neodymium-doped lanthanum nickelate thin films by chemical solution deposition method

Neodymium-doped lanthanum nickelate (La_1 − xNd_xNiO₃, LNNO) thin films have been prepared on Si substrates by chemical solution deposition method. The effects of annealing temperature and the neodymium concentration on the structural and electrical properties of the thin films have been investigated. X-ray diffraction analysis showed that the LNNO thin films exhibited perovskite structure with (100) preferential orientation. The (100) orientation degree of the thin films changed with neodymium content; however, the resistivity of the thin films was not related to the degree of orientation. Field emission scanning electron microscopy observations confirmed that the films had a smooth surface and uniform thickness. The resistivity of the thin films annealed at 700 °C increased from 1.97 mΩ·cm to 5.35 mΩ·cm, with increasing neodymium doping amount from LaNiO₃ to La_0.6Nd_0.4NiO₃.