ZnO thin films prepared by a single step sol-gel process

ZnO thin films were prepared on fused silica from a single spin-coating deposition of a sol-gel prepared with anhydrous zinc acetate [Zn(C₂H₃O₂)₂], monoethanolamine [H₂NC₂H₄OH ] and isopropanol. Crystallization annealing was performed over the range 500 to 650 °C. X-ray analysis showed that thin films were preferentially orientated along the [002] c-axis direction of the crystal. The films had a transparency of greater than 85% in the visible region for sol-gels with a zinc content of up to 0.7 M and exhibited absorption edges at ∼ 378 nm. The optical band-gap energy was evaluated to be 3.298-3.306 eV. Photoluminescence showed a strong emission centered at ca. 380 nm along with a broad yellow-orange emission centered at ca. 610 nm. Single step sol-gel thin film deposition in the film thickness range from 80 nm to 350 nm was demonstrated. The effect of sol-gel zinc concentration, film thickness and crystallization temperature on film microstructure, morphology and optical transparency is detailed. A process window for single spin coating deposition of c-axis oriented ZnO discussed.     

A novel high-throughput fatigue testing method for metallic thin films

Thin films are used in a wide variety of computing and communication applications although their fatigue behavior and its dependence on alloying elements are not very well known. In this paper, we present an experimental implementation of a novel high-throughput fatigue testing method for metallic thin films. The methodology uses the fact that the surface strain amplitude of a vibrating cantilever decreases linearly from the fixed end to the free end. Therefore, a thin film attached to a vibrating cantilever will experience a gradient of strain and corresponding stress amplitudes along the cantilever. Each cantilever can be used to extract a lifetime diagram by measuring the fatigue-induced damage front that progresses along the cantilever during up to 10⁸ load cycles.     

A novel high-throughput fatigue testing method for metallic thin films

Abstract

Thin films are used in a wide variety of computing and communication applications although their fatigue behavior and its dependence on alloying elements are not very well known. In this paper, we present an experimental implementation of a novel high-throughput fatigue testing method for metallic thin films. The methodology uses the fact that the surface strain amplitude of a vibrating cantilever decreases linearly from the fixed end to the free end. Therefore, a thin film attached to a vibrating cantilever will experience a gradient of strain and corresponding stress amplitudes along the cantilever. Each cantilever can be used to extract a lifetime diagram by measuring the fatigue-induced damage front that progresses along the cantilever during up to 10⁸ load cycles.     

(Fe,Co)-P thin films prepared with a reactive evaporation method

Magnetic properties of (Fe,Co)/sub 2/P thin films prepared with the thermal-activated reactive evaporation method were investigated for recording media application. Above 300 degrees C, metals (Fe,Co) and phosphorus react to form M/sub 2/P. The coercive forces of these films had a maximum value of 1.3 kOe at 10% Co concentration, and the saturation magnetization increased with the increase in Co concentration. Annealing at 500 degrees C for 30 min increased the coercive force of the films up to two times. The reproduced output from the isolated magnetization transitions of a (Fe,Co)-P-film rigid disk with a ring head showed waveforms of typical longitudinal recording. A recording density of 62 kfrpi at D/sub 50/ was attained with a disk medium of about an 800-AA-thick layer.<>     

Superhydrophobic polytetrafluoroethylene thin films with hierarchical roughness deposited using a single step vapor phase technique

Superhydrophobic polytetrafluoroethylene films with hierarchical surface roughness were deposited using pulse electron deposition technique. We were able to modulate roughness of the deposited films by controlling the beam energy and hence the electron penetration depth. The films deposited at higher beam energy showed contact angle as high as 166°. The scanning electron and atomic force microscope studies revealed clustered growth and two level sub-micron asperities on films deposited at higher energies. Such dual-scale hierarchical roughness and heterogeneities at the water-surface interface was attributed to the observed contact angle and thus its superhydrophobic nature.     

A simple method for preparing 3D hierarchical carbide derived carbon by single step molten salts electrolysis

In this work, we have proposed a simple, cost-effective and green method for the production of 3D hierarchical carbide derived carbon by single step molten salts electrolysis at 710°C. During the electrolysis process, the high carbon ferromanganese fed manganese and iron ions into molten salts and then those ions were reduced on cathode. At last, there is only porous left on the anode. By XRD and Raman analysis, it was found that the as-prepared porous carbon is composed of amorphous carbon and ordered graphitic carbon with a high degree of graphitization. SEM, TEM and N₂ sorption measurement indicate that this type of CDC has a multimodal pore system consisting of micro-pores, meso-pores and macro-pores.     

A novel tip-induced local electrical decomposition method for thin GeO films nanostructuring

Decomposition of germanium monoxide (GeO) films under the impact of an atomic force microscope (AFM) tip was observed for the first time. It is known that GeO is metastable in the solid phase and decomposes into Ge and GeO(2) under thermal annealing or radiation impact. AFM tip treatments allow us to carry out local decomposition. A novel tip-induced local electrical decomposition (TILED) method of metastable GeO films has been developed. Using?TILED of 10?nm thin GeO film, Ge nanowires on silicon substrates were obtained.     

用于制备ZnO薄膜的金属有机化学气相沉积设备的研制

介绍了一种制备ZnO薄膜的金属有机化学气相沉积(MOCVD)设备,制备的ZnO薄膜主要用作太阳能电池的背反射电极。该设备的极限压力可达5×10-5 Pa,膜厚均匀性偏差在5%以内,薄膜电阻率约为10-2Ω.cm。本文叙述了设备的用途,技术性能,工作过程和结构特点。并对ZnO薄膜的电阻率与参加反应的水蒸汽流量的关系进行了简单介绍。     

基于磁控溅射制备纳米微晶NiO_x薄膜的方法

使用一种配套于磁控溅射设备的基片液氮冷却装置制备了小颗粒度纳米微晶NiOx电致变色薄膜.当溅射参数完全相同时,借助于对基片的冷却可有效控制并降低NiOx薄膜的晶粒尺度.冷却基片所制备的NiOx薄膜的电致变色性能明显优于室温时制备的薄膜,且该薄膜的O/Ni比率也明显高于室温时制备的NiOx薄膜的O/Ni比率.     

金属诱导晶化的实时电阻测量与监控

采用实时电阻测量方法实现了金属镍诱导晶化制备多晶硅薄膜的实时监控,实验中使用了两种样品,一种采用电场增强侧向晶化;另一种采用金属诱导侧向晶化.结果表明薄膜电阻值在高温下随晶化时间呈指数衰减,且具有很强的温度依赖关系.采用晶粒边界势垒模型解释了阻值衰减行为,分析计算了两种样品的阻值衰减规律.电场增强方式的时间常数比非电场增强方式小,表明加电场有促进晶化的作用.实时电阻测量方法可以用于金属诱导晶化动力学的研究,是一种简单实用的实时监控手段.     

Single step deposition method for nearly stoichiometric CuInSe2 thin films

This paper reports the production of high quality copper indium diselenide thin films using pulsed DC magnetron sputtering from a powder target. As-grown thin films consisted of pin-hole free, densely packed grains. X-ray diffraction showed that films were highly orientated in the (112) and/or (204)/(220) direction with no secondary phases present. The most surprising and exciting outcome of this study was that the as-grown films were of near stoichiometric composition, almost independent of the composition of the starting material. No additional steps or substrate heating were necessary to incorporate selenium and create single phase CuInSe₂. Electrical properties obtained by hot point probe and four point probe gave values of low resistivity and showed that the films were all p-type. The physical and structural properties of these films were analyzed using X-ray diffraction, scanning electron microscopy and atomic force microscopy. Resistivity measurements were carried out using the four point probe and hot probe methods. The single step deposition process can cut down the cost of the complex multi step processes involved in the traditional vacuum based deposition techniques.     

Crystallisation of selenium thin films doped with iodine after evaporation

Amorphous selenium thin films deposited under vacuum have been doped with iodine either during or after crystallisation. It is shown that when the films are first crystallised at 363 K for 6 h and then submitted to iodine atmosphere at 363 K for 1 h, the structural properties of the films are not modified while their conductivity increases by a factor of 8. Iodine atmosphere induces post crystallisation of amorphous selenium films even at room temperature by increasing the selenium atom mobility at the surface of the films, which induces growth of crystalline spherulites. With annealing, when the heating rate is high (>15 K/min), constraints appear in the films, the density of spherulites increases and the films are inhomogeneous. When the heating rate is small and constant (1 K/min) the interaction between iodine and selenium takes place all over the sample and there is only a small density of small spherulites, while the crystallisation of the whole sample is more homogeneous. XPS and microprobe analysis that the iodine is equally repartitioned in the selenium film show it. Moreover there is a mixture of neutral iodine andS I₃ ^– as shown by XPS and Raman studies. The high crystalline quality of the films can explain the high conductivity (>10^{–3 –1} cm^–1) of these selenium doped films     

CaMoO4薄膜的电化学制备技术研究

采用恒电流的电化学技术,在高纯金属钼基体上直接制备了白钨矿结构的CaMoO4薄膜;其制备条件为：电流密度0.5mA/cm^2,饱和Ca（OH）2溶液的pH值12.0,反应温度70℃,电化学沉积时间250min.X射线衍射（XRD）、X射线光电子能谱（XPS）和扫描电镜（SEM）分析测试表明,所制备的薄膜为表面均匀致密的四方晶系的CaMoO4单相多晶薄膜.     

A novel patterning technique using super-hydrophobic PTFE thin films by Cat-CVD method

Super-hydrophobic poly-tetrafluoroethylene (PTFE) films, with a water contact angle of over 160°, are formed by catalytic chemical vapor deposition (Cat-CVD) under high catalyzer temperature or pressure. Hydrophobicity of the PTFE films is maintained even after annealing up to 300 °C. We demonstrate a novel method for forming metal lines using super-hydrophobic PTFE films. Water-based functional liquid containing silver nanoparticles dropped on the patterned PTFE film localizes only on hydrophilic regions, resulting in formation of metal lines after annealing up to 150 °C.     

Structure and electrical properties of bismuth thin films prepared by flash evaporation method

Polycrystalline Bi thin films with thickness in the range 40-160 nm have been successfully deposited on glass substrates at 453 K by flash evaporation method for the first time. XRD and FE-SEM were performed to characterize their structure and surface morphology respectively. Electrical resistivity measurement was carried out in the temperature range 300-350 K. Hall coefficient, electron concentration and mobility were measured at 300 K. A distinctly oscillatory behavior has been observed for the electrical properties of the Bi thin films.     

A novel method for preparing vertically grown single-crystalline gold nanowires

A surfactant-free, template-less and seed-less method, namely the thermal-assisted photoreduction (TAP) process, has been developed to synthesize vertically grown Au nanowires (30-80?nm in diameter and about 2?μm in length) on the surface of thin film titanium dioxide (TiO(2)), which is locally excited by blackbody radiation. The Au nanowires thus produced are single-crystalline with a preferred [Formula: see text] growth direction. The electrical behavior investigated using a nanomanipulation device indicates that the Au nanowires possess an excellent electrical resistivity of about 3.49 × 10(-8)?Ω?m.     

Charge carrier and spin doping in ZnO thin films

Recent efforts on doping ZnO films for charge and spin functionality are reviewed, focusing on chemical doping for charge and spin device formation. Discussion includes the behavior of phosphorus as an acceptor and magnetism in transition metal-doped ZnO. Evidence for p-type behavior in phosphorus-doped (Zn,Mg)O grown by pulsed laser deposition is presented. The magnetic properties of ZnO co-doped with Mn and Sn are also discussed.