Dewetting behavior of Au films on porous substrates

Understanding the stability of thin films and their spontaneous pattern formation upon dewetting is essential to a host of physical phenomena. In this paper, we study the dewetting phenomena of Au thin films deposited on anodic aluminum oxide (AAO) membranes to analyze the stability of the metal film on porous substrates. AAO membranes, as-sputtered and dewetted Au films are all characterized by scanning electronic microscopy and X-ray diffraction. We found that both the roughness of AAO surface and modification of AAO pores exhibit remarkable influences on the dewetting behavior of Au films. The observed dewetting phenomena are explained from an energetic point of view since dewetting is a process of minimization of the system free energy.     

Superconducting Bi-Sr-Ca-Cu-O films formed diffusion of metallic bismuth on Sr2Ca2Cu4O y substrates

Superconducting Bi-Sr-Ca-Cu-O films have been prepared on Sr₂Ca₂Cu₄O _y substrates by thermal evaporation of metallic Bi layer and heat-treatment at 830°C for a few minutes in air. The zero resistance temperature of Bi₂Sr₂Ca₁Cu₂O _y film of 1–μm in thickness is about 70 K. The surface diffusion process of Bi on the granular structure of Sr₂Ca₂Cu₄O _y was observed by scanning electron microscope and thermogravimetry analysis. The stripe pattern of superconducting film, typically 2μm thick and 0·3 mm wide, is formed by using a mask.     

Thin photoactive FeS2 (pyrite) films

Thin pyrite films (0.05 – 2 μm) have been prepared by metal organic chemical vapor deposition (MOCVD) employing ironpentacarbonyl and sulphur or hydrogen sulfide. Best photoconductivity was found at a deposition temperature of 130°C, where polycrystalline layers were obtained. The photoactivity of the prepared layers was measured by time-resolved microwave conductivity (TRMC) and by steady state photoconductivity measurements.     

Crystallographic texture and morphology of obliquely deposited Co-Cr magnetic thin films on flexible polymeric substrates

Thin magnetic films of Co-Cr have been obliquely deposited by evaporation and sputtering at a fixed incidence angle of 45° using tilted sample holders. The layers exhibit a columnar microstructure with the column axes at an angle in the range 15°–35° with respect to the film normal. The tilt angle strongly depends on the type of substrate used, the deposition temperature and the substrate pretreatment. The c axes of the h.c.p. crystallites always coincide with the column axes. A Ti underlayer forces the columns and crystallites of the Co-Cr film to grow vertically to the film plane despite the oblique incidence deposition process.     

FeS2/TiO2复合薄膜光电性能

采用溶液浸渍法在ITO导电玻璃表面的多孔TiO2薄膜上沉积了FeS2薄膜.使用Fe2O3粉末保护裸露在外的ITO导电膜在硫气氛中热处理后,制得了FeS2/TiO2复合薄膜.应用B531/H数显测厚指示表、数字式四探针测试仪、XJCM-8太阳电池测试仪等研究了FeS2/TiO2复合薄膜的厚度、ITO导电玻璃的电阻率以及FeS2/TiO2复合薄膜的光电性能.结果表明：此方法制得的FeS2/TiO2复合薄膜具有良好的光电性能;且ITO导电膜的电阻率变化较小.因而适宜制备色素增感太阳能电池（DSSC）.     

Formation of pyrite (FeS2) thin nano-films by thermal-sulfurating electrodeposition films at different temperature

The electrodeposition of iron disulfide pyrite (FeS₂) thin films on indium–tin oxide (ITO) substrate in aqueous solution containing Na₂S₂O₃·5H₂O, FeCl₂·4H₂O reagents was investigated. The deposited material is successively annealed in sulfur atmosphere. In this way, we successfully obtained pyrite thin films with good quality. The structure, optical and electrical property analysis for the resulted films was carried out and some special results have been concluded.     

Two-dimensional nanoparticle arrays formed by dewetting of thin gold films deposited on pre-patterned substrates

We demonstrate the formation of accurate 2D gold nanoparticle arrays via solid-state dewetting on a pre-patterned substrate. The annealing-induced dewetting of Au film on both flat and pre-patterned SiO₂ substrates is investigated. The pre-patterned structures affect clearly the formation of nanoparticles, and there is a depth effect of the pre-patterned grooves on the formation of nanoparticles during dewetting. Especially in pre-patterned areas with deep grid grooves (depth 150 nm) there is almost one single particle formed in the flat areas of every unit square, thus resulting in a very periodic 2D structure of gold nanoparticles.     

硫化压力对电沉积并硫化合成的FeS2薄膜组织结构的影响

采用电沉积及400℃不同压力硫化热处理制备了多晶FeS2薄膜,研究了硫化压力对薄膜晶体结构及微观组织的影响。在较低的硫化压力条件下,电沉积得到的Fe3O4先驱体硫化反应不充分,薄膜组织中FeS2与Fe3O4共存。当硫化压力高于20kPa时,Fe3O4先驱体可充分地转变成具有细小晶粒形态的FeS2,薄膜形貌也由多孔疏松演变为均匀平整。硫化压力在5～40kPa范围内变化对FeS2晶粒尺寸影响不明显,但使FeS2晶格常数略有下降。     

氮氧化铪薄膜在不同衬底上的场发射性能

利用直流溅射法在Si、Zn、Ni三种不同衬底上沉积HfNxOy薄膜并测试了其场发射性能.扫描电子显微镜(SEM)显示HfNxOy薄膜表面由纳米颗粒组成,X射线衍射(XRD)说明薄膜中含有HfN和HfO2两种相.场发射测试结果显示,和金属衬底上的薄膜相比,Si衬底上的薄膜的开启电场小且发射电流密度大.文中对三种衬底上发射电流密度大小不同的原因进行了讨论.电流一时间的对应关系说明HfNxOy薄膜的场发射电流稳定.     

Nanocrystalline silicon films formed under the impact of pulsed excimer laser radiation on polyimide substrates

Polycrystalline silicon films on polyimide substrates were obtained by a method based on the crystallization of amorphous films under the impact of nanosecond pulses of excimer laser radiation. Characteristics of the film structure were studied by methods of Raman scattering and high-resolution electron microscopy. For the laser crystallization regimes employed, nanocrystalline silicon films with an average grain size of 5 nm were obtained. The results are of interest for the development of large-scale microelectronic devices (active thin-film transistor matrices) on cheap flexible substrates.     

Synthesis and characterization of vanadium oxide thin films on different substrates

In this study, the V₈O₁₅ derivative of vanadium oxide was produced on plain glass, indium tin oxide and silicon wafer substrate layers by taking advantage of wet chemical synthesis which is an easy and economical method. The structural properties of the produced films were examined by XRD and SEM analyses. Besides, Al/VO_x/p-Si metal-oxide-semiconductor (MOS) structure was obtained by the same synthesis method. Doping densities of these MOS structures were calculated from frequency dependent capacitance–voltage measurements. It was determined that the interface states which were assigned with the help of these parameters vary according to frequency.     

晶体面缺陷对FeS2薄膜电学性能的影响

采用Fe膜热硫化技术制备了具有不同比表面积和比晶界面积的FeS2薄膜,并测定其载流子浓度和电阻率,研究了FeS2薄膜表面和晶界等面缺陷对FeS2薄膜电学性能的影响.结果表明,表面和晶界两种面缺陷对FeS2薄膜的电学性能有类似的影响规律.在一定范围内,随着薄膜比表面积和比晶界面积的增大,载流子浓度提高而电阻率下降.面缺陷数量的变化可导致FeS2晶体中点缺陷数量、禁带中缺陷能级密度、不充分相变产物比例和相变应力水平的变化,从而导致载流子浓度和电阻率的变化.     

不同衬底制备稀土Nd+3掺杂SnO2薄膜的XRD、SEM分析

采用真空气相沉积法在玻璃和单晶硅衬底[111]上制备纳米SnO2及稀土金属钕掺杂薄膜，并对薄膜进行热处理。对薄膜进行XRD、SEM测试。实验显示，不同衬底制备SnO。薄膜在未掺钕时结构有明显区别，采用同样工艺条件在玻璃衬底上制备的SnO2薄膜没有显示择优生长；在硅衬底上制备未掺钕SnO2薄膜显示出沿[101]晶向择优生长趋势。掺钕（5at％）玻璃衬底制备的薄膜沿[110]衍射峰较强，但薄膜基本呈现自由生长；掺钕后硅衬底制备的薄膜则强烈沿[110]晶向择优生长，随掺钕含量增加择优生长趋势消失，当掺钕含量为（5at％）时薄膜呈自由生长结构较完善。SEM给出在玻璃基片生长的薄膜表面形貌呈均匀小颗粒状，平均晶粒尺寸在30nm左右。硅基片制备的薄膜表面则呈紧密均匀带孔颗粒状；颗粒尺寸约1000nm与计算值相差较大。两种衬底制备的SnO2薄膜经稀土钕掺杂可抑制晶粒生长。本实验中钕掺杂量为5at％（热处理T=500℃，t=45min）时薄膜结构特性最佳。     

多晶FeS2薄膜电学性能的研究与进展

FeS2薄膜是极具研究价值的光电转换材料，改善光电转换效率是主要研究方向，而进一步阐明电传导规律和机制是探索改善FeS2薄膜光电转换效率有效途径的前提之一。本文概述了FeS2薄膜电学性能的研究进展，分析了硫化制备工艺及掺杂效应对FeS2薄膜电学性能的影响，介绍了晶界势垒模型、跳跃传导模型及晶体点缺陷理论等FeS2薄膜电传导相关机制，讨论了FeS2薄膜存在的问题及发展方向。     

Investigation of structural properties of ITO thin films deposited on different substrates

The influence of the substrate nature on the structure and morphology of ITO thin films grown by thermal evaporation in vacuum is investigated. The as-prepared metal films with Sn/In molar ratio of 0.1 were subsequently annealed for 2 h at 723 K in air (to obtain tin doped indium oxide), then annealed in vacuum at 523 K, followed by UV irradiation (to reduce the electrical resistivity). Irrespective of substrate nature, XRD data evidence a (222) preferential orientation in films. Substrate nature, annealing in vacuum and UV irradiation influence the structure, morphology, optical, electrical and surface wetting properties of the films' surface.     

利用电化学技术制备白钨矿薄膜的生长动力学研究

采用恒电流电化学技术直接在金属钼(Mo)或钨(W)片上制备了白钨矿钼酸盐、钨酸盐AMO4(A=Ba、Sr、BaxSr1-x、BaxSryCa1-x-y;M=W、Mo)晶态薄膜,制备时间分别为从薄膜开始生长到薄膜生长结束的不同时间间隔.利用场发射扫描电镜(FESEM)和电子能谱仪(EDX)等测试手段,分别对这些薄膜的生长特性进行了测试,并对测试结果进行了对比分析.结果表明,利用电化学技术制备白钨矿薄膜时,金属基片在不断的溶解;由于负离子配位多面体的沉积、构架和阳离子的不断填充,完成晶核的形成和晶粒的长大;随着时间的增加,光滑饱满的晶粒布满整个基片表面从而完成了薄膜的成膜过程;由于阳离子Ba2+、Sr2+、Ca2+填充速率依次降低,使得在沉积二元和三元薄膜时出现富钡现象.     

不同衬底上LaNiO3导电氧化物薄膜的制备和研究

通过MOD法和快速热处理过程,在Si(100)和Pt(111)/Ti/SiO2/Si衬底上制备了LaNiO3(LNO)导电氧化物薄膜.经XRD结构分析表明,所制备的LNO薄膜具有纯的钙钛矿结构,并且以(100)方向择优取向.经SEM和AFM分析表明,LNO薄膜具有表面均匀、无裂纹.经标准四探针法测试表明,LNO薄膜具有好的金属特性,其室温电阻率为7.6×10-4Ω·cm.铁电性能测试表明,LNO薄膜可以提高PZT铁电薄膜的剩余极化强度.