电子功能外延薄膜的电沉积

电沉积作为一种在温和条件下从溶液中合成材料的技术已被广泛应用于在导体和半导体基底表面合成各种功能材料。电沉积一般由人为施加于基底的电刺激（如：施加电位/电流）来触发。这种电刺激通过氧化或还原靠近基底表面的溶液层内部的离子、 分子或配合物从而使该溶液层偏离其热力学平衡状态,随后引起目标产物在基底表面的沉积。在电沉积过程中, 许多实验参数都可能从不同的方面对沉积物的物化性质造成影响。迄今为止,已通过电沉积制备出多种单质（包括金属和非金属单质）、 化合物（例如：金属氧化物、金属氢氧化物、 金属硫化物等）以及复合材料。电沉积制备的这些材料大多为多晶、 织构或外延薄膜的形式。其中, 外延薄膜是一种具有特定的面外和面内晶体生长取向且其晶体取向受基底控制的类单晶薄膜。由于外延薄膜中高度有序的原子排列,它们常呈现出独特的电磁性质。本文总结了常见的电沉积合成路线及影响沉积物外延生长的关键实验因素。此外, 本文简要介绍了用于表征外延薄膜的技术。最后, 本文还讨论了一些采用电沉积制备的具有特殊电子、 电磁及光电特性的功能外延薄膜。     

液晶金属配位聚合物的合成及性能

基于国内外最新研究文献 ,系统论述了近年来液晶金属配位聚合物的合成方法、液晶行为及应用前景。指出液晶金属配位聚合物的合成方法可归纳为直接配位法、单体配位法、交联配位法和聚合物反应法四种。液晶金属配位聚合物一般呈现热致液晶行为 ,显示稳定的向列液晶相或近晶液晶相。有些金属配位聚合物还呈现互变性近晶态或单变液晶性。液晶金属配位聚合物具有金属的特殊性质 ,是一种新型高性能磁导、电导和光导材料 ,可望应用于液晶显示材料、磁性信息储存薄膜材料、润滑剂和各向异性催化剂等。     

非晶纳米高熵合金薄膜Nd-Fe-Co-Ni-Mn的电化学制备及磁学性能

通过电沉积方法在室温下制备了具有纳米结构组织的Nd-Fe-Co-Ni-Mn高熵合金磁性薄膜。 通过改变电沉积参数,如沉积电位、沉积时间,可控制薄膜的纳米结构及表面形貌。 扫描电子显微镜观察结果表明,在Ti基体上,-2.2 V下沉积5 min可制备出大小在200 nm左右的均匀分布的球形颗粒薄膜,延长沉积时间会使薄膜变得更加致密,而沉积电位的负移会导致纳米片的出现。 能谱结果表明5种元素发生了共沉积,结构分析表明该薄膜是无定形态的。 稀土元素Nd与过渡金属发生共沉积,可能是由于过渡金属离子与二甲基亚砜形成多核配位化合物而使得过渡金属离子沉积电位负移所致。 Nd-Fe-Co-Ni-Mn高熵合金薄膜在室温下具有良好的软磁性能。     

二维过渡金属硫属化合物的大面积制备与应用研究进展

二维过渡金属硫属化合物(TMDs)因具有可调带隙、 谷电子学性质和高催化活性等优点, 在电子学、 光电子学和能源相关领域受到广泛关注. 为了实现以上应用, 实现大面积、 厚度均匀TMDs薄膜的批量制备至关重要. 化学气相沉积法(CVD)是制备大面积均匀、 高质量二维材料普遍使用的方法. 本文从前驱体的供给和衬底的设计两个角度, 总结了目前合成大面积TMDs薄膜的CVD方法, 并讨论了高质量TMDs的生长机制和参数优化方法; 介绍了高质量TMDs在电子学、 光电子学和电/光催化等方面的应用; 讨论了目前合成大面积均匀、 高质量TMDs所面临的挑战, 并对该领域的发展方向进行了展望.     

一种耐高温聚苯并嗪的电化学合成

苯并噁嗪最先由 Holly和 Cope在 1 944年通过曼尼奇反应由苯酚、甲醛、胺合成而得 [1] .苯并嗪能够热聚合 .Ishida等 [2 ]在这方面做了大量工作 ,总结了热聚合苯并嗪的两种基本方法 .此外 ,某些苯并嗪还能象聚酚那样通过电化学方法沉积在金属表面形成聚合物来保护金属不受腐蚀[3] .但由于所得聚合物处于绝缘态 ,往往得不到自支撑的聚合物薄膜 .本文从乙腈 /氢氧化钠水溶液的混合溶液体系中成功地合成了一种新的自支撑的聚苯并嗪薄膜 ,其在空气中的热分解温度达 3 60℃ ,对酸、碱表现出很好的化学惰性 ,是一种很好的电极防腐材料 .…     

石墨型碳氮聚合物纳米结构的研究进展

石墨型碳氮聚合物指的是主要由碳氮两种元素结合形成具有类石墨层状共轭结构的聚合物.由于具有类石墨的共轭平面结构,这类聚合物可形成各种纳米结构材料,如球状、管状、带状、薄膜以及介孔材料等.这些材料密度低、硬度高、化学惰性、生物相容性好等,同时具有光学和电学性质,因而在催化、生物技术、气体存储、超硬材料、光学和电子材料、金属...     

用金属有机化合物燃烧化学沉积α-Al2O3纳米陶瓷膜

提出了直接在空气中沉积纳米陶瓷薄膜的新方法———燃烧化学沉积法。以沉积αAl2O3为例,用异醇铝溶于易燃溶剂甲苯中形成原始溶液,将该溶液雾化并穿过氧乙炔火焰,在火焰前方的基体上形成了αAl2O3纳米陶瓷薄膜。提出了火焰体系化学反应的相变动力学公式,按完全燃烧原理和流体连续方程计算出专用喷嘴的原料液体流量及氧压力,并进行雾化试验,确定出合理的耗氧量,对可能由于工艺参数不合适导致的不均匀生长进行了分析,提出了合理的工艺参数。结果表明,用金属有机化合物溶于易燃溶剂中进行燃烧制备纳米陶瓷薄膜的工艺方法是可行的。     

衬底温度对ZnO薄膜生长过程和微结构的影响

从原子尺度上去研究薄膜生长过程中温度对薄膜取向性、缺陷结构以及薄膜完整性的影响和作用规律, 对于解释薄膜生长的物理本质、控制生长条件、提高薄膜制备的质量具有重要意义. 本文应用基于反应力场的分子动力学方法研究了ZnO薄膜(000l)表面作为衬底的薄膜沉积生长过程, 初步讨论了衬底温度(200、500和800 K)变化对沉积较薄ZnO膜质量的影响, 部分结果与实验观察相符. 结果表明, 衬底温度在500 K左右时, 沉积原子结构径向分布函数曲线特征峰尖锐、明显, 有序度较高, 注入和溅射对薄膜完整性影响较小, 沉积形成的薄膜结构稳定而又致密. 在预置衬底表面平坦的情况下薄膜呈现一种链岛状的生长模式, 每原子层均具有两种生长取向, 导致其生长前锋交汇处形成了一种新的有序缺陷.     

喷墨打印聚合物薄膜均匀性调控研究进展

聚合物发光显示材料具有发光颜色在全可见光区可调、可溶液简单加工及适用于柔性大面积基底的特点,成为目前研究的热点。 在聚合物发光薄膜图案化技术中,喷墨打印因为具有加工过程简单高效、适用于溶液方式加工、柔性的加工过程等特点而被认为是最具有应用潜力的技术。 高质量聚合物薄膜的制备是高精度发光显示器件制作的关键,但喷墨打印液滴在干燥过程中通常伴随着“咖啡环”现象,造成薄膜不均匀沉积。 因此,消除“咖啡环”现象,实现聚合物薄膜的均匀沉积,是喷墨打印高性能器件的重要研究方向。 本文主要论述了“咖啡环”效应的产生机理,如何抑制喷墨打印聚合物薄膜加工过程中的“咖啡环”效应,最终实现聚合物薄膜均匀性调控。     

聚苯胺-TCNQ复合薄膜的微观结构与电学特性

聚苯胺 (ＰＡＮＩ)作为高聚物材料 ,具有稳定性好 ,易于合成等优点．它在化学传感器、显示器、光化学电池等光电器件上有着许多潜在的应用前景．目前导电聚苯胺材料的合成、薄膜的制备与表征正在受到人们的重视．由于聚苯胺很难溶于一般的有机溶剂 ,用化学方法通过聚合物溶液用旋涂或自组装的方法成膜具有很大的局限性 ,特别是不易得到实用化的薄膜产物．而用真空蒸发沉积方法制备聚苯胺薄膜却有成膜质量高、易于控制 ,能很好与电子及微电子加工工艺相接轨等优点［１ -３］．国外已有一些关于真空蒸发沉积聚苯胺薄膜的研究报导［２ -５］,但…     

Epitaxial ternary nitride thin films prepared by a chemical solution method

It is indispensable to use thin films for many technological applications. This is the first report of epitaxial growth of ternary nitride AMN2 films. Epitaxial tetragonal SrTiN2 films have been successfully prepared by a chemical solution approach, polymer-assisted deposition. The structural, electrical, and optical properties of the films are also investigated.     

A surface adsorption model for electroless cobalt alloy thin films

Thin cobalt alloy films have been obtained using electroless deposition solution with two reducing agents: dimethylamine borane (DMAB) and sodium hypophosphite. This system allows spontaneous and self-activated deposition of barrier layers on Cu lines and via contacts for ultra large scale integration (ULSI) interconnects applications. This work presents a study of the solution composition effects on the material properties and composition of the films. First, we present the deposition rates, the electrical resistance, the various element profiles in the thin film, and the thin film roughness. Next, we discuss the film’s composition and its dependence on the ratio between the reducing agents composition in the solution. The experimental results suggest that the film phosphorous and boron composition is determined by the surface adsorption rates of the reducing agents. Therefore, a surface co-adsorption model of the two reducing agents is proposed, formulated, analyzed, and compared to the experimental results. Finally, we discuss the model and its significance to the formation of high-quality ultra-thin barrier layers. Dedicated to Professor Dr. Algirdas Vaskelis on the occasion of his 70th birthday.     

Monte Carlo simulation on layered polymeric films

Thin films of polymer blends composed of alternating copolymer, diblock copolymer and/or homopolymer are studied using Monte Carlo simulation. A multilayer morphology is observed in the film, that is, the blended polymers assemble into individual domains arranged from interior to the surfaces of the film. The coexisting components residing throughout the neighboring domains in the film make no distinguishable interface between any neighboring domains. By this means, it forms a vertical composition gradient in the polymeric film. Being different from layer-by-layer deposition of polyelectrolyte or hydrogen bonding approach etc., the layered structure in this study is formed by polymer blending in one step. Alternating copolymers are found to be essential components to form vertical composition gradient （layered structure） in thin films.     

Aqueous Chemical Solution Deposition of Functional Double Perovskite Epitaxial Thin Films

Double perovskite structure (A₂BB′O₆) oxides exhibit a breadth of multifunctional properties with a huge potential range of applications in fields as diverse as spintronics, magneto-optic devices, or catalysis, and most of these applications require the use of thin films and heterostructures. Chemical solution deposition techniques are appearing as a very promising methodology to achieve epitaxial oxide thin films combining high performance with high throughput and low cost. In addition, the physical properties of these materials are strongly dependent on the ordered arrangement of cations in the double perovskite structure. Thus, promoting spontaneous cationic ordering has become a relevant issue. In this work, our recent achievements by using polymer-assisted deposition (PAD) of environmentally friendly, water-based solutions for the growth of epitaxial ferromagnetic insulating double perovskite La₂CoMnO₆ and La₂NiMnO₆ thin films on SrTiO₃ and LaAlO₃ single-crystal substrates are presented. It is shown that the particular crystallization and growth process conditions of PAD (very slow rate, close to thermodynamic equilibrium conditions) promote high crystallinity and quality of the films, as well as favors spontaneous B-site cationic ordering.     

Early Stages of CeO2 Thin-film Nucleation and Growth with Photo Irradiation

In this paper, the early stages of nucleation and photoirradiation growth of CeO₂ thin films have been studied. Cyclic voltammetry, chronoamperometry and scanning electron microscopy were used to analyze the nucleation process of CeO₂ thin films deposited on the anode with photo irradiation. Experimental results show that the anodic deposition process with photo illumination is controlled by diffusion. Compared with the dark state, photo illumination mainly contributed to increase the current density of the three-dimensional nucleation process, because photo illumination is helpful to create active sites and accelerate the nucleation progress on the surface that a thin ceria film has been formed. Two-dimensional nucleation process mainly exists within the initial 2 s, and then only three-dimensional instantaneous nucleation process continues, which may be the main reason why the thickness of the CeO₂ film can continue to grow with photo illumination but not in the dark state. Increasing the deposition overpotential can promote two-dimensional nucleation and growth rate, whilst when the potential exceeds 0.65 V, three-dimensional current density decreases. The li-miting factor at that time may be the diffusion rate of cerium ions in the solution towards the electrode substrate.     

Pulsed Laser Deposition‐based Thin Film Microbatteries

Emerging applications for robust small format or distributed devices feature a need for power and rechargeable lithium‐ion batteries could play a significant role. This review focuses on a high precision technique to controllably grow thin‐film electrodes or full all‐solid‐state batteries, that is, pulsed laser deposition (PLD). The technique and solid‐state batteries are introduced followed by a detailed showcase of the depth of PLD‐based growth undertaken on cathodes, electrolytes, anodes and whole microbatteries. Emphasis is placed on the various characterization techniques available to study PLD grown components and devices, and how interfaces become both critical and arguably easier to probe in PLD grown films or devices. This work provides a perspective on the techniques, its opportunities for electrodes and devices, and how to probe the resulting growth and its evolution in batteries.     

Gold cluster formation on a fullerene surface

The growth of Au clusters on a fullerene thin film was investigated by in situ photoelectron spectroscopy in the ultraviolet (UPS) and x-ray (XPS) regime. Due to its highly corrugated surface fullerene films provide a wide range of bonding sites which could be exploited as molecular templates and serve to create a cluster superstructure. To gain insight into the fullerene-Au interaction two types of experiments were performed: (i) the deposition of Au on a fullerene surface, and (ii) the deposition of fullerenes on a Au surface. In both experiments an island growth mode is observed. The deposition of submonolayer amounts of C60 onto a gold film showed that the main interaction of the two species is due to chemisorption of the first C60 monolayer. In addition a constant band bending in the fullerene film is detected, but the UPS valence-band spectra show that there is no charge transfer from the Au to the C60 lowest unoccupied molecular orbital. In the reverse experiment, the cluster growth of Au on the corrugated C60 surface, the analysis of the Au core level does not reveal a specific bonding or nucleation site for Au atoms and clusters. This is in contrast to observations with Si clusters, which prefer to reside in the troughs between the fullerene molecules. The Au clusters grow continually from a size of about 55 atoms for the early stages of growth up to 150 atoms for the deposition of a nominal coverage of 1.5 nm. These data are derived from an analysis of the d-band splitting and the Au 4f core-level shift due to delayed photohole relaxation. The thermal stability of the Au-clusters-covered fullerene film was investigated by annealing in situ up to temperatures of 650 degrees C. For temperatures up to 450 degrees C a continuous growth of the clusters is detected, which is accompanied by a slight drop in Au concentration in the range of XPS for annealing temperatures higher than 350 degrees C. This may be due to a ripening of the clusters. The presence of Au apparently delays fullerene sublimation. The film shows a very good thermal stability and even after annealing at 650 degrees C there is still a fullerene film detectable in the photoelectron spectroscopy spectra.     

Controlled Nanopores in Thin Films of Nonstoichiometrically Supramolecularly Assembled Graft Copolymers

Herein, nanometer‐scale morphologies of graft‐copolymer‐like supramolecular thin films, composed of sulfonic acid terminated polystyrene (SPS) and poly(2‐vinylpyridine) (P2VP), and their application to antireflection coatings were investigated. The intermolecular complexes of SPS and P2VP, formed through nonstoichiometric multiple hydrogen bonding between the sulfonic acid group of SPS and the nitrogen atom in pyridine unit of P2VP, occurring in film deposition allowed for the formation of spherical micelles (with SPS and P2VP as the corona and core, respectively) in the thin film. Interestingly, the domain size of the micelles was tunable from approximately 20 to 90 nm on average by controlling either the blend ratio of components or the concentration of polymer solution. Furthermore, nanoporous thin films could be easily prepared by removing the core of micelle‐based nanostructures by using a simple solvent etching process, leaving sulfonic acid groups on the surface of nanopores, which can be utilized as potential functional sites. Those resultant nanoporous thin films were conveniently employed as an antireflection layer on a glass substrate, giving a maximum 97.8 % transmittance in the visible wavelength range.     

Analytical characterization of thin carbon films

CH(x) films on silicon substrates deposited by a Mesh Hollow Cathode Process (MHC) were analyzed by various techniques. The films were produced with varying deposition times, resulting in thicknesses ranging from ~2-20 nm. X-Ray Reflectivity (XRR) was used to determine the film thicknesses and the deposition rate. A good correlation of measured XRR thicknesses with SIMS sputter depths down to the film-substrate transition was found.An AFM-based nanoscratching technique was applied to test the wear resistance of the thin overcoats. The MHC films reveal slightly decreasing scratch resistance for reduced film thicknesses, which can be explained by a higher fraction of soft interface zones for thinner films.This is in accordance with Raman spectroscopic measurements in the visible spectral range which were carried out to examine the carbon bonding properties. Combined analysis of G peak position and D/G peak intensity ratio indicates a more graphitic structure for film thicknesses less than 10 nm.     

激光刻蚀模板中电沉积特殊结构CIGS薄膜

本文利用激光刻蚀模板,在水溶液中电沉积制备金属铜薄膜,讨论了温度、电流、硫酸铜浓度对薄膜形貌的影响. 采用SEM对制备的铜薄膜进行表征,结果表明在沉积温度为30 ℃,沉积电流为4 A·dm^-2(表观工作电流密度),硫酸铜浓度在20 ~ 50 g·L^-1的水溶液中电沉积可以得到中空馒头状和开口碗状结构的铜薄膜. 利用激光刻蚀模板,在离子液体1-丁基-3-甲基咪唑三氟甲磺酸盐([BMI][TfO]) - 30 Vol%丙醇混合电解质中电沉积CIGS薄膜,研究了沉积电势、沉积时间对薄膜形貌的影响. SEM观察发现,在沉积电势为-1.8 V,沉积时间为1.5 h条件下电沉积可以得到近似柱状的簇状花束样的CIGS薄膜, 电沉积铜后再进一步电沉积CIGS,得到了均匀有序的鼓包柱状结构的Cu/CIGS复合薄膜. 用恒电势方波法对制备的薄膜真实表面积进行测试,计算结果表明,与无模板电沉积制备的CIGS薄膜相比,激光刻蚀模板法制备的Cu/CIGS复合薄膜的表面积提高了约8倍.