ZnO∶Ti透明导电薄膜的制备与光电性能研究

采用直流磁控溅射法,在水冷7059玻璃衬底上制备了具有高透射率和相对低电阻率的掺钛氧化锌(ZnO∶Ti)透明导电薄膜,研究了溅射偏压对ZnO∶Ti薄膜结构、形貌和光电性能的影响。结果表明,ZnO∶Ti薄膜为六角纤锌矿多晶结构,具有c轴择优取向。溅射偏压对ZnO∶Ti薄膜的结构和电阻率有重要影响。当溅射偏压为10V时,电阻率具有最小值1.90×10–4?.cm。薄膜具有良好的附着性能,可见光区平均透射率超过90%。该ZnO∶Ti薄膜可以用作薄膜太阳能电池和液晶显示器的透明电极。     

Deposition of morphology-tailored PbS thin films by surfactant-enhanced aerosol assisted chemical vapor deposition

In this work, we report the results of deposition of PbS thin films using single molecular precursor, bis(O-isobutylxanthato)lead(II), in the presence of additives namely: sodium dodecyl sulfate (SDS), Tween and Triton x-100, via aerosol assisted chemical vapor deposition (AACVD). The as-deposited PbS thin films are highly crystalline and exhibited superior adhesion to glass substrates. Powder X-ray diffraction (XRD) analysis confirmed the formation of pure cubic phase of PbS. Thin films deposited using 0.4 mM Triton X-100 as additive resulted in wire like structures while 0.8 mM Triton X-100 deposited thin films comprised of predominantly shoe shaped structures. Further, increase in concentration (1.2 mM) of Triton X-100 deposited films having rod like morphology. The scanning electron microscopy (SEM) confirmed that in the presence of SDS, thin films consist of spherical shaped crystallites. Energy dispersive X-ray spectroscopy (EDX) and X-ray photon electron microscopy (XPS) of as-deposited PbS thin films was used to study chemical composition of thin films.     

Deposition of Bismuth Telluride Thick Film by Solidification under Centrifugal Pressure

Bismuth telluride alloys—Bi_0.5Sb_1.5Te₃ and Bi_1.8Sb_0.2Te_3.33Se_0.17—have been deposited on polycrystalline zirconia via solidification under centrifugal pressure. The crystal growth under centrifugal pressure was a process in which the starting powders charged in the groove patterns of the substrates were first melted and then solidified under centrifugal acceleration of 10⁴ m/s². This new process offers c-axis-oriented films with a thickness of more than 100 μm. A mirror-like surface is another characteristic feature of these films. Owing to their orientation, reasonable power factors such as 4.2 mW/m K² and 2.7 mW/m K² (in plane) were obtained for p- and n-type films, respectively.     

Deposition,opto-electronic and structural characterization of polymorphous silicon thin films to be applied in a solar cell structure

In this study we analyze the optoelectronic properties and structural characterization of hydrogenated polymorphous silicon thin films as a function of the deposition parameters. The films were grown by plasma enhanced chemical vapor deposition (PECVD) using a gas mixture of argon (Ar), hydrogen (H₂) and dichlorosilane (SiH₂Cl₂). High-resolution transmission electron microscopy images and Raman measurements confirmed the existence of very different internal structures (crystalline fractions from 12% to 54%) depending on the growth parameters. Variations of as much as one order of magnitude were observed in both the photoconductivity and effective absorption coefficient between the samples deposited with different dichlorosilane/hydrogen flow rate ratios. The optical and transport properties of these films depend strongly on their structural characteristics, in particular the average size and densities of silicon nanocrystals embedded in the amorphous silicon matrix. From these results we propose an intrinsic polymorphous silicon bandgap grading thin film to be applied in a p–i–n junction solar cell structure. The different parts of the solar cell structure were proposed based on the experimental optoelectronic properties of the pm-Si:H thin films studied in this work.     

Paramagnetic-to-antiferromagnetic phase transformation in sputter-deposited Ni-Mn thin films

Sputter-deposited, equiatomic Ni-Mn thin films were observed to possess a metastable, nanocrystalline, chemically disordered, fcc (A1) structure. Grain growth and a phase change to a chemically ordered, antiferromagnetic L1₀ structure were identified by x-ray diffraction (XRD) and transmission electron microscopy (TEM). Differential scanning calorimetry (DSC) experiments revealed exothermic signals that correspond to the grain growth and phase transformation reactions. The enthalpy of transformation for the A1 to L1₀ phase change was calculated as −3.5 kJ/mol, which agress with thermodynamic modeling. An activation energy of 139 kJ/mol was calculated for the phase transformation by the Kissinger method.     

Deposition,post-deposition annealing,and characterization of epitaxial Ge films grown on Si(100) by pyrolysis of GeH4

As a first step towards developing heterostructures such as GaAs/Ge/Si entirely by chemical vapor deposition, Ge films have been deposited on (100) Si by the pyrolysis of GeH₄. The best films are grown at 700° C and are planar and specular, with RBS minimum channeling yields of ≈4.0% (near the theoretical value) and defect densities of 1.3 x 10⁸ cm⁻². Variations of in-situ cleaning conditions, which affect the nature of the Si substrate surface, greatly affect the ability to get good epitaxial growth at 700° C. The majority of the defects found in the Ge films are extrinsic stacking faults, formed by dissociation of misfit and thermal expansion accommodation dislocations. The stacking fault density is not significantly reduced by post-deposition annealing, as is the case for the dislocations observed in MBE Ge films. It is suggested that lowering the CVD growth temperature through the use of high vacuum deposition equipment would result in dislocation defects like those of MBE films which could then be annealed more effectively than stacking faults. Films with defect densities equivalent to MBE Ge films (~2 x 10⁷ cm⁻²) could then probably be produced.     

氮化铝薄膜的低温沉积

介绍了一种 ECR微波放电和脉冲激光沉积相结合低温沉积 Al N薄膜的新方法 .在 ECR氮等离子体环境中用脉冲激光烧蚀 Al靶 ,以低于 80℃的衬底温度在 Si衬底上沉积了 Al N薄膜 .结合样品表征和等离子体光谱分析 ,探讨了膜层沉积的机理 ,等离子体中活性氮物质的存在是 Al- N化合的重要因素 ,等离子体对衬底的辐照促进膜层的形成     

Comparative study of electrically conductive thick films with and without glass

An air-fireable, glass-free, electrically conductive thick-film material (96.6% Ag, 1.38% Cu, 0.28% Al, 0.35% Ti, and 1.39% Sn by weight) and a conventional glass-containing, electrically conductive thick-film materials (96.6% Ag and 3.4% glass frit by weight), both on alumina substrates, were studied by electrical, mechanical, thermal, and microscopic methods. The volume electrical resistivity of the glass-free thick film (2.5×10⁻⁶ Ω·cm, 30-μm thick) is lower than that of the glass-containing thick film (3.9×10⁻⁶ Ω·cm, 19-μm thick), with each film processed at its optimum firing temperature. The optimum firing temperature is 930°C and 850°C for glass-free and glass-containing thick films, respectively, as indicated by the criteria of low resistivity and high scratch resistance. The glass-free thick film has a higher scratch resistance than the glass-containing thick film, both fired at their respective optimum temperatures, suggesting that the former has higher bond strength to the alumina substrate. The formation process of the glass-free and glass-containing thick films is similar. The process involves solid-state diffusion of silver, which results in a silver network and grain boundaries. However, the sintering of silver particulates in the glass-containing thick film is enhanced by the viscous flow of glass.     

Effects of complexing Agents on three Steps pulse Electrodeposited SnS thin films

SnS thin films were prepared on indium-tin-oxide (ITO)-coated glass substrate at room temperature via three steps pulse electrodeposition from an aqueous bath containing 30 mM SnSO₄ and 100 mM Na₂S₂O₃. The effects of two complexing agents, i.e., ethylenediaminetetraacetic (acid-EDTA [CH₂N(CH₂COOH)₂]₂) and L(+)-tartaric acid (C₄H₆O₆) under different concentration were studied. All the deposited samples exhibited p-type conductivity behaviour. The films deposited with the complexing agents generally showed less oxygen content and larger sulfur content than those deposited without the agents. The film thickness was decreased by addition of EDTA and low concentration of tartaric acid (<10 mM), while it was slightly increased with a large amount of tartaric acid (>30 mM). Larger crystalline size and larger optical transmission were observed for SnS deposited with tartaric acid concentration larger than 30 mM.     

脉冲激光沉积法制备氧化锌薄膜

ZnO是一种新型的Ⅱ-Ⅵ族半导体材料,具有优良的晶格、光学和电学性能,其显著的特点是在紫外波段存在受激发射。利用脉冲激光沉积法(PLD)在氧气氛中烧蚀锌靶制备了纳米晶氧化锌薄膜,衬底为石英玻璃,晶粒尺寸约为28-35 nm。X射线衍射(XRD)结果和光致发光(PL)光谱的测量表明,当衬底温度在100-250℃范围内时,所获得的ZnO薄膜具有c轴的择优取向,所有样品的强紫外发射中心均在378-385 nm范围内,深能级发射中心约518-558 nm,衬底温度为200℃时,得到了单一的紫外光发射(没有深能级发光)。这归因于其较高的结晶质量。     

脉冲激光双光束沉积掺Mg的GaN薄膜的研究

采用脉冲激光双光束沉积系统在Si(111)衬底上生长了掺Mg的GaN薄膜和未掺杂GaN薄膜。利用X射线衍射(XRD)、原子力显微镜(AFM)、室温范德堡霍尔测量及光致发光(PL)光谱对两类薄膜进行对比分析，结果显示，所生长的GaN薄膜均为六方纤锌矿晶体结构，掺Mg可细化所生长的GaN薄膜晶粒。随着掺Mg量的增加，GaN薄膜无需后处理即可由”型导电转化为p型导电，GaN薄膜的光学性能随p型载流子浓度增大而提高；然而掺Mg却导致GaN薄膜结晶质量下降，掺镁量过大的GaN薄膜中p型载流子浓度反而减少，光致发光中黄发射峰增强较大。研究表明通过优化脉冲激光双光束沉积参数无需任何后处理可直接获得高空穴载流子浓度的p型GaN薄膜。     

Site‐Selective Deposition of Nanostructured ZnO Thin Films from Solutions Containing Polyvinylpyrrolidone

When soluble zinc salts are hydrolyzed in water, usually elongated micrometer‐sized zincite crystals are formed. In this study, polyvinylpyrrolidone (PVP) in a methanolic solution is used as an agent to control the morphology of the deposition product. It prevents crystal growth and yields zinc oxide nanocrystals. Thin films consisting of zinc oxide nanocrystals are formed on self‐assembled monolayers (SAMs) of sulfonate‐terminated alkylsiloxanes. Patterned films are deposited after local decomposition of the SAM by UV irradiation. The films fabricated from methanolic solutions containing PVP are particularly smooth, uniform and stable. Their thickness is determined by the deposition time and the molar ratio [PVP]:[Zn²⁺], so that films of arbitrary thickness and nearly constant roughness can be obtained. The crystal grains are oriented preferentially with 〈001〉 direction perpendicular to the substrate surface. The films show ultraviolet, orange‐red and green‐yellow photoluminescence; the latter is quenched by heat treatment. Based on the obtained experimental results, a deposition mechanism is suggested.     

石英衬底上溅射制备纳米SiCN薄膜

利用射频溅射方法在石英玻璃上沉积了纳米结构硅碳氮(SiCN)薄膜. SiCN薄膜表面由平均直径约50nm的SiCN纳米颗粒组成，这些纳米颗粒的紧密分布构造了薄膜的致密表面. 纳米SiCN薄膜呈现出典型的半导体导电特征. 通过调整N2流量参数可以获得不同带隙的SiCN薄膜材料，这种带隙可调的纳米结构SiCN薄膜在未来的半导体光电器件应用领域会有广阔的应用前景.     

Reactive ion beam deposition of aluminum nitride thin films

Aluminum nitride thin films have been prepared at room temperature by reactive ion beam sputtering for potential use as a passivant and diffusion/anneal cap in compound semiconductor technology. The electrical and optical pro-perties of these films have been studied along with the in-fluence of thermal annealing on the material characteristics. The quality of the films has also been found to improve in the presence of atomic hydrogen during the deposition.     

Characterization of Si-N films prepared by reactive ion beam sputtering

Application of silicon-nitride (Si-N) as a passivant in com-pound semiconductor technology requires a low-temperature deposition process to prevent dissociation of the volatile constituents of the semiconductor. With this in mind, an exploratory study of Si-N films prepared at room temperature using low-energy, reactive ion-beam sputtering has been carried out. The electrical and optical characteristics of the films have been studied, and an annealing step is found necessary to reduce the conductivity of the nitride and im-prove the interfacial properties. On leave of absence from the Department of Physics, Kurukshetra University, Kurukshetra-132119, India.     

Degradation transformation in spinel-type functional thick-film ceramic materials

The mathematical models of thermally-induced degradation processes in solids with nano- and microscale topological disordering – bulk and thick-film ceramic composites based on mixed transition-metal manganites are considered. It was shown that degradation transformations in these materials are best described by stretched or suppressed exponential relaxation function. The stretched exponential degradation kinetics is proper to own degradation transformations in such one-type systems as bulk ceramics and multilayered thick-film structures. The mechanism of degradation transformations in one-layered thick films, including two or more different on their origin elementary are described by suppressed exponential kinetics.     

Chemical Solution Deposition of Silver Halide Films

Chemical solution deposition of semiconductor films has been confined almost entirely to chalcogenides. Here, we extend this technique to halide films. Silver halides (AgI, AgBr, and AgCl) were deposited using in‐situ homogeneous hydrolysis of organic haloalcohols to form halide ions that react with silver ions in aqueous solution. Also, a rapid precipitation method is described that gives AgCl films. Structural (XRD), morphological (TEM), and optical (transmission spectra) characterizations of the films are presented. Some preliminary results and ideas on other halide films are presented.     

离子束溅射氧化物薄膜的中红外特性

以离子束溅射沉积(IBSD)方法制备了Al2O3、Nb2O5单层膜,用红外可变角度光谱椭圆偏振仪(IR-VASE)测试了薄膜的光学常数。用原子力显微镜(AFM)测量了单层膜的表面形貌及表面粗糙度,计算了单个表面的总积分散射(TIS)。以Nb2O5和Al2O3为高低折射率材料设计并制备了2.7μm高反射膜。最后对单层膜进行了环境实验检测。结果表明,制备的薄膜在中红外波段具有高的折射率和低的消光系数,光滑的表面特性和极低的表面散射损耗;在2.7μm波段没有发现由于水吸收导致的消光系数的增大;制备的反射膜在2.7μm反射率达到了99.63%,接近于理论计算值。薄膜顺利通过了一系列环境实验,显示其优良的环境稳定性。     

White light photoluminescence from ZnS films on porous Si substrates

ZnS films were deposited on porous Si (PS) substrates using a pulsed laser deposition (PLD) technique.White light emission is observed in photoluminescence (PL) spectra, and the white light is the combination of blue and green emission from ZnS and red emission from PS. The white PL spectra are broad, intense in a visible band ranging from 450 to 700 nm. The effects of the excitation wavelength, growth temperature of ZnS films, PS porosity and annealing temperature on the PL spectra of ZnS/PS were also investigated.     

Deposition of diamond from alcohol precursors in an electron cyclotron resonance plasma system

Microstructural control is a critical issue in the use of diamond films in a variety of engineering applications. Using a novel, electrostatic-based particle seeding process, we have investigated the deposition of diamond films with varying areal nucleation densities. Depositions were performed at low pressures (1.000 and 1.500 Torr) in a modified electron cyclotron resonance plasma system. Methyl alcohol was the primary diamond precursor species. Scanning electron microscopy and Raman spectroscopy were used to evaluate microstructure and composition characteristics. Comparisons in deposition characteristics were made based on relative nucleation density and gas-phase composition.