封面图片说明

正封面图片出自论文"纳米结构的倾斜角度沉积及性能优化".是清华大学材料学院张政军教授研究团队提供的倾斜角度沉积过程示意图及制备的不同形貌纳米棒状结构的电镜照片.倾斜角度沉积是指以较大的角度(大于75°)倾斜入射沉积薄膜,通过控制沉积束流与基底法线的夹角α和基底绕自身法线自转的速度ω,再根据沉积速率和具体材料的不同,可制备出具有特定形貌(如螺旋形、折线形纳米结构)及优异性能(如抗反射性能、表面增强拉曼性质)的纳米结构.它具有适用     

离子液体添加剂对电沉积氢氧化镁薄膜形貌的影响

以离子液体[MEIM]+[ES]-为晶体生长调控剂,采用简便的电化学方法合成了特定形貌的氢氧化镁纳米结构薄膜.对影响电沉积氢氧化镁薄膜的合成参数(如离子液体的含量、沉积电位和沉积时间)进行了研究,并分别用电镜、X射线衍射和热分析技术对所得氢氧化镁薄膜的形貌和热稳定性进行了表征.此外,该电化学过程可望推广到制备其它形貌独特和性能奇特的纳米/介观结构.     

酞菁铜/氧化钛纳米复合薄膜的制备及其光导性能的研究

通过电化学阳极氧化法在Ti片上制备了氧化钛(TiO2)纳米管阵列.用这种高度有序的阵列结构作为模板,利用电泳沉积的方法在模板表面沉积了一种有机半导体材料酞菁铜(CuPc),从而得到了CuPc/TiO2有机/无机纳米复合结构.通过场发射扫描电镜(FESEM),透射电镜(TEM)等手段对这种复合结构的表面形貌及结构进行了表征.能谱数据证实了复合结构中有机物的存在.此外,CuPc薄膜的形貌和结构可以通过改变电泳沉积参数(如沉积时间和电压)进行调控,从而得到相应的纳米晶、纳米线和微米线薄膜.用该复合薄膜作为载流子发生层制备的双层光导体的光导性能测试结果表明,与复合前的氧化钛薄膜相比,该复合薄膜的光敏性有明显的提高.     

脉冲电沉积法制备纳米材料的研究进展

纳米材料具有特殊的磁性、光学、力学、电学、电化学催化等性能,而脉冲电沉积技术在制备纳米材料方面应用广泛且优点多.着重列举了脉冲电沉积技术在制备纳米晶材料、纳米复合材料、纳米析氢材料、纳米金属薄膜及纳米金属多层膜、纳米线材料等方面的应用,总结了纳米材料的一些特点,展望了脉冲电沉积技术制备纳米材料的前景.     

高致密度FeNi纳米颗粒薄膜制备与性能研究

传统磁控溅射装置制备的纳米颗粒薄膜粒径不均一并且实现粒径大小调控比较困难。本研究采用电场辅助沉积技术,在沉积平台施加5~30 kV的电场,以Si(100)为衬底制备了一系列纳米颗粒粒径均一的高致密度FeNi纳米颗粒薄膜材料。通过XRD、SEM以及VSM测量,研究了不同沉积电场下FeNi纳米颗粒薄膜的结构、形貌和磁性能。利用单端口短路微带线法对0.5~5.5 GHz范围内的微波磁谱进行表征。实验结果表明:沉积电场越大,纳米颗粒粒径均一且薄膜的致密度越高,越有利于薄膜综合磁性能的改善和饱和磁化强度增大。薄膜材料微波磁谱表明,电场辅助沉积技术制备的软磁薄膜材料能够在GHz频段得到广泛应用。     

氧化锌纳米棒形貌对ZnO/Cu2O异质结太阳能电池光伏性能的影响

采用电化学沉积法制备了ZnO纳米棒,首先讨论了电化学沉积参数对氧化锌(ZnO)纳米棒形貌的影响,并对不同长度ZnO纳米棒的光吸收和反射等性质进行了研究.实验发现沉积时间是影响纳米棒长度、直径的重要因素,ZnO纳米棒的微观形貌对其光学性质有重要影响.然后以氧化锌纳米棒为n型材料,以氧化亚铜为p型材料,通过电化学沉积法构筑了ZnO/Cu2O异质结太阳能电池,并测试了其光伏性能,研究表明增长纳米棒阵列的长度使得开路电压、短路电流密度及光电转换效率等性能得到提升.最后,综合分析了氧化锌纳米棒形貌与所组装电池的性能之间的关系,发现调控氧化锌纳米棒的形貌是提高ZnO/Cu2O异质结太阳能电池光伏性能的有效途径.     

常压化学气相沉积硅镀膜玻璃结构、表面形貌与光学性能比较研究

本文通过高分辨电镜(HREM)、原子力显微镜(AFM)分析,反射率、透射率测试以及薄膜厚度的测试,研究了常压化学气相沉积法硅镀膜玻璃硅薄膜的结构、表面形貌(颗粒数量、大小和分布)对镀膜玻璃反射率、透射率的影响.研究发现不同的制备工艺(沉积温度和基板走速)对薄膜的平均反射率和平均透过率有很大的影响,通过控制合适的工艺参数可以制得具有纳米颗粒镶嵌结构的复合薄膜.具有此种形貌结构的薄膜能在基本部增大透过率的情况下有效减少薄膜镜面反射,减少光污染.     

纳米电缆材料的研究进展

纳米电缆材料因其独特的光学性能、电学性能、磁学性能及几何结构而成为当今纳米材料研究领域的热点和重点.介绍了纳米电缆的研究进展、纳米电缆的结构和制备技术的发展状况,详细阐述了电弧放电、化学气相沉积、毛细管虹吸等多种制备方法,并展望了纳米电缆的发展和应用前景,纳米电缆的研究对于以纳米材料为基础而构筑的微纳米器件有着重要的意义.     

微波等离子体化学气相沉积方法制备纳米金刚石薄膜

为了制备出大面积均匀连续的纳米金刚石薄膜,并探索温度、气氛等条件对最终生长出的纳米金刚石薄膜样品的影响,使用微波等离子体化学气相沉积(MPCVD)方法,改变CH_4、H_2、Ar气体比例以及衬底温度,在不同生长条件下制备了5组金刚石薄膜样品。5组样品分别使用ESEM和拉曼光谱进行成膜质量、形貌、结构以及组分的表征,分析了不同薄膜的成因和工艺参数的影响,并提出了进一步优化的方向。     

预处理基底上择优取向的ZnO纳米柱的制备

在预处理基底上,采用化学溶液沉积法在低温下制备氧化锌纳米柱薄膜.通过X射线衍射(XRD)和扫描电镜(SEM)表征了氧化锌纳米柱的形貌和晶体结构.研究表明,控制制备过程中的工艺条件:氨水含量、烧结温度、沉积温度、ZnCl2浓度,可以达到优化氧化锌纳米柱的形貌和晶形取向的目的,最后得到单分散性、规整、高度取向的氧化锌纳米柱.并利用晶体生长理论和预处理基底的形貌表征等对反应机理、晶体取向进行讨论.     

Dünne Schichten durch Deposition unter streifenden Einfall

Micro‐ and nanostructured thin films by Glancing angle deposition Physical vapour deposition under conditions of obliquely incident flux and limited adatom diffusion results in films with a columnar microstructure. These columns will be oriented toward the vapour source. An additional substrate rotation can be used to sculpt the columns into various morphologies (slanted and vertical posts, chevrons, screws or spirals). With this glancing angle deposition (GLAD) technique can prepared porous thin films with engineered structures from a variety of dielectric, semiconducting and metallic materials. The paper presents the In this paper the physical fundamentals of the GLAD technique are introduced, the production of micro‐ and nanostructures of different morphology on non‐patterned and patterned substrates is demonstrated and some possible applications of this new deposition technique are introduced.     

Nanostructure engineering in porous columnar thin films: recent advances

Glancing angle deposition (GLAD) is a physical vapour deposition method used to fabricate highly functional thin films with an engineerable columnar morphology. Recent developments in GLAD technology have produced columnar nanostructures of increased complexity, including periodic, nanofibrous, perforated, and graded porosity thin films for use in applications ranging from sensors and actuators to optical filters, microfluidics, and catalysis. A brief review of GLAD methodology and historical developments is followed by a discussion of the latest developments in this field.     

Indium tin oxide nanowhisker morphology control by vapour-liquid-solid glancing angle deposition

A new growth technique for indium tin oxide nanowhiskers with increased control over feature size and spacing is reported. The technique is based on a unique combination of self-catalysed vapour-liquid-solid (VLS) growth and glancing angle deposition (GLAD). This VLS-GLAD technique provides enhanced control over nanowhisker morphology as the effect of typical VLS growth parameters (e.g.?flux rate, temperature) is amplified at large deposition angles characteristic of GLAD. Spatial modulation of the collimated growth flux controls trunk width, number and orientation of branches, and overall nanowhisker density. Here we report the influence of growth conditions (including deposition angle, flux rate, nominal pitch and substrate temperature) on nanowhisker morphology, with specific focus on the effect of large deposition angles. Sheet resistance and transmission of the films were measured to characterize their performance as transparent conductive oxides. Hybrid nanostructured films grown in this study include high surface area nanowhiskers protruding from a conductive film, ideal for transparent conductive electrode applications.     

Periodically structured glancing angle deposition thin films

Thin films fabricated using the glancing angle deposition technique have a porous microstructure consisting of freestanding columns. Many promising applications of such thin films require that the columns be arranged in periodic arrays using substrate topographies-so-called seed layers-that enforce controlled film nucleation. In this paper, we present the optimized design, fabrication, and characteristics of periodically structured thin films, achieving highly uniform periodic film morphologies. We derive geometrical rules for designing substrate seed layers, and explain how to fabricate large area seed patterns with submicrometer features. Using negative-resist electron-beam lithography and laser direct write lithography, we have reached extremely high pattern densities. An experimental analysis is provided of seed-enforced nucleation and thin-film growth, showing that the elimination of film growth between seeds is crucial, and that the substrate seed layer geometry must match the intended film microstructure. Finally, we discuss the enhanced properties of periodically structured oblique angle thin films and their applications.     

Fabrication and optical characterization of template-constructed thin films with chiral nanostructure

We report the fabrication of thin films perforated by high aspect ratio helical or chevron pores by an extension of the glancing angle deposition (GLAD) technique. The perforated films were created by transferring the nanostructure of a GLAD template film into target materials such as polymers and spin-on-glasses and subsequently removing the template. The pore shapes are shown to be highly controllable and films designed to suit particular applications are discussed. By a double templating technique, we replicate the structure of the original film using alternate materials, which are typically less suited to the unmodified GLAD technique. Helical films of Cu and Ni were created by this method and the process should be transferable to additional electrodeposited materials. The optical rotatory power of perforated thin films formed on glass substrates was characterized and perforated films were shown to be effective in rotating the polarization plane of linearly polarized incident light by as much as 1.4/spl deg///spl mu/m.     

Overcoming cap layer cracking for glancing-angle deposited films

Porous thin films deposited by glancing-angle deposition (GLAD) have found application as sensor, micro-electrical mechanical systems and microfluidic devices. However, conventional micro-fabrication techniques can damage the very properties which make GLAD films attractive for these applications. To facilitate integration of GLAD films with these processes, a capping layer may be used. Such capping layers must be as free of defects as possible to ensure that the GLAD film is well protected. Here, the cracking properties of evaporated TiO₂ caps deposited on GLAD films have been investigated as a function of substrate temperature. Our films are a porous vertical post layer 2.7 μm thick capped with a solid 400 nm layer. This material system experiences tensile stress from two sources: thermal mismatch between the film and substrate, and intrinsic stress in the cap from Volmer-Weber coalescence. Crack properties such as crack length distribution, crack density and branch number were quantified. In general, higher substrate temperatures reduced crack density, branch number and preferentially eliminated longer cracks. The onset of crystallinity at substrate temperatures around 300 °C briefly increases crack area and branch number, but a further reduction can be achieved by depositing above this temperature. Applications of films grown by GLAD requiring high-quality capping layers will benefit from this study.     

电泳沉积及其在新型陶瓷工艺上的应用

介绍了电泳沉积的特点、悬浮液的稳定机制、电泳沉积的机理及动力学原理,并对该技术在制备固体表面陶瓷涂层、孔状结构陶瓷、多层及复合结构、固体氧化物电池、纳米材料及纳米结构陶瓷上的应用进行了总结。     

In situ synthesis and characterization of GaN nanorods through thermal decomposition of pre-grown GaN films

Herein we describe a thermal treatment route to synthesize gallium nitride (GaN) nanorods. In this method, GaN nanorods were synthesized by thermal treatment of GaN films at a temperature of 800?°C. The morphology and structure of GaN nanorods were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that GaN nanorods have a hexagonal wurtzite structure with diameters ranging from 30 to 50?nm. Additionally, GaN nanoplates are also founded in the products. The growth process of GaN nanostructures was investigated and a thermal decomposition mechanism was proposed. Our method provides a cost-effective route to fabricate GaN nanorods, which will benefit the fabrication of one-dimensional nanomaterials and device applications.     

Surface engineering of synthetic nanopores by atomic layer deposition and their applications

In the past decade, nanopores have been developed extensively for various potential applications, and their performance greatly depends on the surface properties of the nanopores. Atomic layer deposition （ALD） is a new technology for depositing thin films, which has been rapidly developed from a niche technology to an established method. ALD films can cover the surface in confined regions even in nanoscale conformally, thus it is proved to be a powerful tool to modify the surface of the synthetic nanopores and also to fabricate complex nanopores. This review gives a brief introduction on nanopore synthesis and ALD fundamental knowledge, and then focuses on the various aspects of synthetic nanopores processing by ALD and their applications, including single-molecule sensing, nanofiuidic devices, nanostructure fabrication and other applications.     

Fabrication and characterization of nanostructures on insulator substrates by electron-beam-induced deposition

The fabrication, characterization, and decoration with metallic nanoparticles of nanostructures such as nanowhiskers, nanodendrites, and fractal-like nanotrees on insulator substrates by electron-beam-induced deposition (EBID) are reviewed. Nanostructures with different morphologies of whiskers, dendrites, or trees are fabricated on insulator (Al₂O₃ or SiO₂) substrates by EBID in transmission electron microscopes by controlling the irradiation conditions such as the electron beam intensity. The growth of the nanostructure is related to the accumulation of charges on the surface of a substrate during electron-beam irradiation. A high concentration of the target metallic element and nanocrystal grains of the element are contained in the fabricated nanostructures. The process of growth of the nanostructures is explained qualitatively on the basis of mechanisms in which the formation of the nanostructures is considered to be related to the nanoscaled unevenness of the charge distribution on the surface of the substrate, the movement of the charges to the convex surface of the substrate, and the accumulation of charges at the tip of the grown nanostructure. Novel composite structures of Pt nanoparticle/tungsten (W) nanodendrite or Au nanoparticle/W nanodendrite are fabricated by the decoration of W nanodendrites with metallic elements. Because they have superior features, such as a large specific surface area, a freestanding structure on substrates, a typical size of several nanometers of the tip or the branch, and high purity, the nanostructures may have applications in technologies such as catalysts, sensors, and electron emitters. However, there are still some subjects that should be further studied before their application.