柔性衬底氧化物半导体透明导电膜的研究进展

回顾和评述了柔性衬底氧化物透明导电膜（包括锡掺杂的三氧化二铟ITO薄膜、铝掺杂的氧化锌AZO薄膜等）的研究进展情况。报道了在柔性衬底上制备的ITO膜、ZnO膜的光电性质对衬底种类、制备工芑及制备参数的依赖关系，给出了在此领域内应进一步进行的工作。     

柔性透明导电膜衬底材料的研究进展

综述了柔性透明导电膜材料的应用以及可用作柔性透明导电膜衬底材料的种类、存在的问题和可行的解决方法。介绍了柔性透明导电膜材料的优点、应用和国内外研究现状。重点介绍了可用作柔性透明导电膜衬底的聚合物材料—聚酰亚胺和聚酯,分析了各自的特点。通过分析柔性衬底存在的不足,寻求可行的解决方法,使柔性衬底可以更好地满足导电膜对衬底材料的要求,为柔性衬底材料的设计提供依据。     

掺铝氧化锌透明导电膜的研究进展

掺铝氧化锌(AZO)透明导电薄膜作为一种性能优异的多功能材料引起了研究人员的普遍关注,被认为是当前极具发展潜力的传统铟锡氧化物(ITO)薄膜的替代者.综述了AZO薄膜的不同制备工艺,并叙述了衬底温度、Al掺杂量、氧分压、退火条件、同质缓冲层5个因素对薄膜的结构以及光电性能的影响.针对AZO透明导电薄膜的研究现状,提出了今后的研究方向:理论与经验相结合,优化工艺设备,在提高薄膜透光率的同时进一步降低其表面电阻和制造成本,并不断开拓AZO薄膜新的应用领域.     

射频磁控溅射有机衬底SnO2：Sb透明导电膜性能的研究

采用射频磁控溅射法在聚丙烯己二酯有机薄膜(polypropylene adipate, PPA)衬底上低温制备出锑掺杂的氧化锡(SnO2∶Sb)透明导电膜.研究了薄膜的厚度效应对SnO2∶Sb薄膜的结构、光学和电学特性的影响.制备薄膜为多晶膜,并且保持了纯二氧化锡的金红石结构.载流子浓度和迁移率随着薄膜厚度的增加而增大,电阻率随着薄膜厚度的增加而减小,最低电阻率为 2×10-3Ω*cm.     

射频磁控溅射有机衬底SnO2∶Sb透明导电膜性能的研究

采用射频磁控溅射法在聚丙烯己二酯有机薄膜(polypropylene adipate, PPA)衬底上低温制备出锑掺杂的氧化锡(SnO2∶Sb)透明导电膜.研究了薄膜的厚度效应对SnO2∶Sb薄膜的结构、光学和电学特性的影响.制备薄膜为多晶膜,并且保持了纯二氧化锡的金红石结构.载流子浓度和迁移率随着薄膜厚度的增加而增大,电阻率随着薄膜厚度的增加而减小,最低电阻率为 2×10-3Ω*cm.     

可用于沉积透明导电氧化物薄膜的柔性衬底研究进展

柔性衬底表面沉积TCO薄膜具有许多独特的优点且应用广泛.但柔性衬底存在不耐高温的缺点,如何选择合适的柔性衬底,在表面沉积TCO薄膜过程中至关重要.简单介绍了各种柔性衬底的相关性能,阐述了当前国内外在该领域中各柔性衬底的研究成果,展望了未来柔性衬底的选择及应用趋势.     

NiO/Ag/NiO透明导电膜光电特性研究

在室温条件下, 利用磁控溅射法在玻璃衬底上制备了NiO/Ag/NiO透明导电膜, 研究了不同NiO层和Ag层厚度对三层膜可见光透过率和电阻特性的影响。结果分析表明:制备的NiO/Ag/NiO为N型透明导电膜。在400~800 nm的可见光区域内, 随着NiO和Ag层厚度的增加, 薄膜的透光率先增大后减小。NiO层厚度为30 nm且Ag层厚度为11 nm时, 叠层膜具有较好的光学特性, 其最大透过率为84%, 薄膜电阻为3.8Ω/sq, 载流子浓度为7.476×10²¹cm^-3。对薄膜透过率进行了计算机模拟, 发现结果与实验中大致趋势相同, 但因为折射率选择和薄膜界面等因素的影响, 在可见光区域后半段实验值大于计算值。     

氧化锌透明导电薄膜的制备及其特性

氧化锌薄膜的透明导电特性与化学计量偏离和溅射条件有关。以２％氧化铝掺杂的氧化锌陶瓷作靶,采用ＦＲ磁控溅射技术制备的透明导电薄膜,其电阻率４．５＊１０＾－３Ωｃｍ,载流子浓度２．８＊１０＾２０ｃｍ＾－３,霍尔迁移率１５．８ｃｍ＾２／Ｖ．ｓ平均透射率大于８０％。     

铝锆共掺杂氧化锌透明导电薄膜的低温制备及特性研究

利用直流磁控溅射法在室温玻璃衬底上制备出了可见光透过率高、电阻率低的铝锆共掺杂氧化锌(ZAZO)透明导电薄膜。讨论了溅射功率对ZAZO薄膜结构、形貌和光电性能的影响。实验结果表明,溅射功率对ZAZO薄膜的结构、形貌和电学性能有很大影响,而对其光学性能影响不大。扫描电子显微镜和X射线衍射仪研究结果表明,ZAZO薄膜为六方纤锌矿结构的多晶薄膜,具有垂直于衬底方向的c轴择优取向。当溅射功率为120 W时,薄膜的电阻率达到最小值5.28×10-4Ω.cm,其可见光区平均透过率超过94%。     

超薄金属透明导电膜及其应用研究进展

透明导电薄膜被广泛地应用于显示、太阳能电池、发光二极管等光电子器件。近年来,随着信息技术和新材料的不断革新,柔性电子器件在显示、能源及可穿戴等领域得以迅速发展,这对透明导电薄膜的柔性化提出了新的挑战。相比于其他类型柔性透明导电薄膜,超薄金属导电薄膜具有柔性好、导电性好、光电性能均匀、稳定性好、成本低和可大规模制备等优点,有望成为替代ITO的理想材料。超薄金属薄膜的生长和其光电特性息息相关。与常规电介质衬底相比,金属普遍具有较大的表面能,因而金属薄膜在衬底表面通常按照岛状模式生长,阈值厚度高。对薄膜厚度低于阈值厚度的金属薄膜而言,在电学特性方面,纳米团簇形貌使电子在薄膜晶界和表面被过多散射,电子迁移率受到抑制,从而导致电阻率较高。而在光学特性方面,离散的纳米团簇也会引起局域表面等离子体共振,使超薄金属薄膜的透过率曲线在特定波长处明显下降。尽管进一步增加薄膜厚度可以降低电阻率,但厚度的增加会使透过率下降。因此,金属薄膜的超薄、低阈值厚度连续生长是同时获得良好的光学和电学特性的关键。已有的降低超薄金属薄膜阈值厚度的方法包括添加氧化物缓冲层和金属种子层、表面处理、掺杂及低温沉积等。其中添加氧化物的方法因可选择材料种类丰富、制备工艺简单可控等优点,成为制备超薄金属薄膜最普遍的方法;引入金属种子层和掺杂的方法可有效提高金属薄膜的润湿性,然而,其他金属的引入会带来薄膜光学损耗的问题;表面处理的方法对薄膜光学性能的影响较小,其利用聚合物分子层的官能团与金属原子间的键合作用抑制金属原子的扩散;对温度精确控制的要求较高和设备昂贵使低温沉积法的推广面临挑战。本文概述了超薄金属透明导电薄膜的最新研究进展,归纳总结了超薄金属薄膜的生长模式、电学特性和光学特性,重点介绍了降低超薄金属薄膜阈值厚度、实现薄膜连续化生长的多种方法及原理,分析了超薄金属薄膜在太阳能电池、OLEDs、长程表面等离子体激元波导以及Low-E涂层领域的应用情况。最后讨论了超薄金属透明导电膜未来的发展方向。     

Mechanical properties of ZnO thin films deposited on polyester substrates used in flexible device applications

ZnO is growing in importance as a functional film in flexible devices because of the wide range of electrical properties that can be achieved through appropriate doping and the relative abundance of Zn. We have deposited ZnO films with various thicknesses by sputtering on polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) flexible substrates and measured their mechanical properties using compression and scratch tests coupled with in-situ optical microscopy. The cracking of ZnO, during compression, is thickness dependent and at lower thicknesses the films sputtered on PEN exhibit the highest crack onset strains, around 2%. During scratch testing, two major scratch failure mechanisms are observed, analyzed and discussed. It is also found that scratch resistance of ZnO is thickness dependent for both PET and PEN. At high scratch loads a secondary failure mechanism due to impregnation of film debris into the polymer substrates is observed.     

Ga-Ti共掺杂ZnO透明导电薄膜的微观结构和光电性能研究

采用磁控溅射方法在玻璃基片上制备了Ga-Ti共掺杂ZnO(GTZO)透明导电薄膜,通过XRD、四探针仪和分光光度计测试,研究了氩气压强对GTZO薄膜光电性能和晶体结构的影响。结果表明:所有GTZO薄膜均为(002)择优取向的六角纤锌矿结构,其光电性能和晶体结构与氩气压强密切相关。当氩气压强为0.4Pa时,GTZO薄膜具有最大的晶粒尺寸(85.7nm)、最小的压应力(-0.231GPa)、最高的可见光区平均透射率(86.1%)、最低的电阻率(1.56×10-3Ω·cm)和最大的品质因子(4.28×105Ω-1·cm-1),其光电综合性能最佳。另外,采用光学表征方法计算了薄膜的光学能隙和折射率,并利用有效单振子理论对折射率的色散性质进行了分析,获得了GTZO薄膜的色散参数。     

Properties of ZnO:Al films deposited on polycarbonate substrate

Transparent conducting aluminum-doped zinc oxide (ZnO:Al) films have been prepared on polycarbonate (PC) substrates by pulsed laser deposition technique at low substrate temperature (room-100 °C); Nd-YAG laser with wavelength of 1064 nm was used as laser source. The experiments were performed at various oxygen pressures (3 pa, 5 pa, and 7 Pa). In order to study the influence of the process parameters on the deposited (ZnO:Al) films, X-ray diffraction and atomic force microscopy were applied to characterize the structure and surface morphology of the deposited (ZnO:Al) films. Polycrystalline ZnO:Al films having a preferred orientation with the c-axis perpendicular to the substrate were deposited with a strong single violet emission centering about 377–379 nm without any accompanying deep level emission. The average transmittances exceed 85% in the visible spectrum for 300 nm thick films deposited on polycarbonate.     

ZnO:Al films deposited by in-line reactive AC magnetron sputtering for a-Si:H thin film solar cells

Throughout the last years strong efforts have been made to use aluminium doped zinc oxide (ZnO:Al) films on glass as substrates for amorphous or amorphous/microcrystalline silicon solar cells. The material promises better performance at low cost especially because ZnO:Al can be roughened in order to enhance the light scattering into the cell. Best optical and electrical properties are usually achieved by RF sputtering of ceramic targets. For this process deposition rates are low and the costs are comparatively high. Reactive sputtering from metallic Zn/Al compound targets offers higher rates and a comparable high film quality in respect to transmission and conductivity. In the presented work the process has been optimised to lead to high quality films as shown by reproducible cell efficiencies of around 9% initial for single junction amorphous silicon solar cells on commercial glass substrates. The crucial point for achieving high efficiencies is to know the dependency of the surface structure after the roughening step, which is usually performed in a wet etch, on the deposition parameters like oxygen partial pressure, aluminium content of the targets and temperature. The most important insights are discussed and the process of optimisation is presented.     

Preparation and character of textured ZnO:Al thin films deposited on flexible substrates by RF magnetron sputtering

ZnO:Al thin films deposited on transparent TPT substrates by magnetron sputtering were etched in acetic acid solution. The effects of etching solution concentration and etching time on the structure and properties of ZnO:Al films were investigated. The obtained films had a hexagonal structure and a highly preferred orientation with the c-axis perpendicular to the substrate. The ZAO film etched in 1% acetic acid solution for 10 s had a pyramidal structure and an enhanced light scattering ability, the average transmittance and reflectance in the visible region were 72% and 26% respectively, the sheet resistance was 260 Ω/□. Both transmittance and reflectance of the films decreased as the etching solution concentration and etching time increasing. Etching had a negative effect on the conductive properties of ZAO films. The lowest sheet resistance was 120 Ω/□ for the ZAO film without etching.     

Ellipsometric studies on ZnO:Al thin films: Refinement of dispersion theories

We characterize sputter-deposited aluminum-doped zinc oxide (ZnO:Al) thin films on glass and silicon substrates by variable-angle spectroscopic ellipsometry in the spectral range of 240 nm to 1700 nm. The model dielectric function includes the excitonic effects of direct band-gap semiconductors in the presence of high carrier densities as well as the scattering of free carriers by ionized donors. We show that an energy-dependent broadening term of the band-gap model avoids an extended absorption tail below the absorption threshold as it usually results from Lorentzian broadening. Uniaxial anisotropy takes account of the oriented growth of hexagonal crystalline ZnO:Al thin films. All the parameters derived from the optical measurements such as surface roughness, free-carrier concentration and mobility agree with the results of independent thin-film characterization methods such as atomic-force microscopy, Hall and four-point probe measurements. In the case of the glass samples, we need an additional interface layer which is confirmed by transmission-electron microscopy as an intermix layer of ZnO and glass.     

Multifunctional ZnO:V thin films deposited by rf-magnetron sputtering from aerogel nanopowder target material

ZnO:V thin films have been grown onto suprasil substrates by rf-magnetron sputtering at room temperature using nanocrystalline powder synthesized by modified sol-gel method. In our approach the water for hydrolysis used in the synthesis of nanopowder was slowly released by esterification reaction followed by a thermal drying in ethyl alcohol at 250 °C. The effects of V concentration on structural, electrical, morphological and optical properties were studied. The as-deposited films with a thickness of about 0.4 μm were polycrystalline with a hexagonal wurtzite structure and preferentially oriented in the (002) crystallographic direction. The films present high optical transmittance in the visible range of approximately 90%, carrier concentration of about 10²⁰ cm^− 3 and electrical resistivity of 10^− 3 Ω cm at room temperature. In the as-prepared state the films also present ferromagnetic properties attributed to the presence of vanadium based secondary phases.     

Mn-doped ZnO transparent conducting films deposited by DC magnetron sputtering

Mn-doped zinc oxide (ZnO:Mn) thin films with low resistivity and relatively high transparency were firstly prepared on glass substrate by direct current (DC) magnetron sputtering at room temperature. Influence of film thickness on the properties of ZnO:Mn films was investigated. X-ray diffraction (XRD) and scanning electron microscopy (SEM) show that all the deposited films are polycrystalline with a hexagonal structure and have a preferred orientation along the c-axis perpendicular to the substrate. As the thickness increases from 144 to 479 nm, the crystallite size increases while the electrical resistivity decreases. However, as the thickness increases from 479 to 783 nm, the crystallite size decreases and the electrical resistivity increases. When film thickness is 479 nm, the deposited films have the lowest resistivity of 2.1 × 10^− 4 Ω cm and a relatively high transmittance of above 84% in the visible range.