Influence of substrate on properties of gold nanolayers

Gold layers were prepared by sputtering on polyethylene (PE) and glass. Sheet resistance, thickness, surface morphology and crystal structure of the layers were studied by two-point technique, gravimetry, AFM and XRD. Under the same conditions the growth rate of the layer is higher on the glass. On the glass a shorter sputtering time is needed for creation of an electrically continuous layer. Roughness of the underlying substrate affects roughness of deposited gold layer. From XRD analysis it was found that the gold layers deposited onto glass and PE digger by biaxial strength, size of crystallites and number of micro-deformations.     

退火处理对MgO薄膜性能的影响

采用磁控溅射法在石英衬底上制备了MgO薄膜并分别在不同温度下进行退火处理。利用X射线衍射仪(XRD)和扫描电子显微镜(SEM)研究了MgO薄膜的结构和表面形貌随退火温度的变化,发现退火可以改善薄膜的结晶质量,即随着退火温度的升高,晶粒尺寸逐渐增大,结晶性能更佳,表面更加平整。此外,通过紫外-可见光分光光度计研究了MgO薄膜光学特性的变化,发现随着薄膜退火温度的升高,可见光透射率下降,光学带隙值逐渐减小。     

磁控溅射硅钼薄膜的抗氧化性能研究

用射频磁控溅射法在单晶Si基体上制备了硅钼薄膜,对薄膜进行真空退火处理以及高温氧化实验,借助SEM和X射线衍射仪(XRD)等仪器对退火前后的薄膜以及高温氧化后的薄膜进行了分析。结果表明沉积态的硅钼薄膜为非晶态,高温真空退火使薄膜由非晶态转变为晶态,致密的复合氧化物是硅钼薄膜具有良好的抗氧化性能的主要原因。     

Local surface morphology and chemistry of SnO2 thin films deposited by rheotaxial growth and thermal oxidation method for gas sensor application

In this paper experimental results of a comparative X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and X-ray Photoelectron Spectroscopy (XPS) study of the crystalline structure, the local morphology, and the surface and in-depth chemistry of SnO₂ thin films obtained by Rheotaxial Growth and Thermal Oxidation (RGTO) method are presented. XRD rules out even a minor presence of a coexisting SnO phase. AFM and SEM show a fractal like morphology of nanograins (20 nm typical size) agglomerated in clusters of crystallites with a bimodal size distribution. XPS shows that the surface of the SnO₂ crystallites is slightly under-stoichiometric as expected from the oxygen deficient termination of their facets. Noteworthy, as evidenced by XPS depth profiles, there are no significant changes of the surface chemistry of the RGTO film with argon ion sputtering.     

Crystalline hydroxyapatite thin films produced at room temperature — An opposing radio frequency magnetron sputtering approach

Hydroxyapatite (HA) films have been widely recognized for their biocompatibility and utility in promoting biointegration of implants in both osseous and soft tissue. Conventional sputtering techniques have shown some advantages over the commercially available plasma spraying method; however, the as-sputtered films are usually amorphous which can cause some serious adhesion problems when post-deposition heat treatment is necessitated. In this paper we present an opposing radio frequency (RF) magnetron sputtering approach for the preparation of HA thin films on various substrates at low power levels. Using this alternative RF magnetron geometry, as-sputtered HA films are nearly stoichiometric, highly crystalline, and strongly bound to the substrate. Post-deposition heat treatment under 800 °C did not result in a marked improvement in the degree of crystallinity of the films. In addition, dissolution experiments show that as-sputtered films are more stable than annealed ones. As-sputtered films grown on amorphous silica substrates exhibit X-ray diffraction (XRD) patterns similar to those of randomly orientated HA powder. On the other hand, films deposited on oriented substrates such as Si(100) and Si(111) show a polycrystalline HA XRD pattern but with some strongly preferred orientations, indicating that HA crystallization is sensitive to the nature of the substrate. The results suggest that the opposing RF magnetron sputtering approach has some potential to produce high quality HA films on metallic implants.     

退火温度对纳米TiO2薄膜的乙醇气敏特性的影响

采用直流磁控反应溅射法分别在Al2O3陶瓷管和Si(111)基片上制备纳米TiO2薄膜.首先将样品置于马孚炉中,分别在500℃、700℃和1100℃下进行3小时退火处理,然后利用XRD测定各退火条件下TiO2薄膜的晶粒尺寸和晶型,并对样品的气体敏感特性进行测试.实验结果表明:薄膜的结构、晶粒尺寸、晶相和气敏特性随着退火温度的不同而变化,经过500℃×3小时退火后的TiO2薄膜(锐钛矿相)对乙醇蒸汽的灵敏度最高,响应(恢复)时间为2-3s,并具有很好的选择性,其最佳工作温度为280℃左右.最后讨论了薄膜的乙醇气敏机理.     

Correlation study between structural, magnetic and transport properties of annealed Co thin films

This paper presents structural, magnetization and transport properties measurements carried out on as-deposited Co (400 Å) thin film as well as samples annealed in the temperature range 100-500 °C in steps of 100 °C for 1 h. The samples used in this work were deposited on float glass substrates using ion beam sputtering technique. The magnetization measurements carried out using MOKE technique, clearly indicates that as-deposited as well as annealed samples up to 500 °C show well saturation magnetization with applied magnetic field. The as-deposited sample shows coercivity value (H_c) of 26 Oe, and it is increased to 94 Oe for 500 °C-annealed sample. A minimum coercivity value of 15 Oe is obtained for 200 °C annealed sample. The XRD measurements of as deposited films show microcrystalline nature of Co film, which becomes crystalline with increase in annealing temperature. The corresponding resistivity measurements show gradual decrease in resistivity. AFM technique was employed to study the surface morphology of as deposited film as well as annealed thin films. Observed magnetization, and resistivity behaviour is mainly attributed to the (i) change in crystal structure (ii) increase in grain size and (iii) stress relaxation due to the annealing treatment.     

新型氧敏CeO2-x薄膜的制备及结构研究

用射频磁控溅射法制备了CeO2-x高温氧敏薄膜。通过改变O2／Ar比，制备出不同组分和结构的CeO2-x薄膜。用Ce3d的XPS谱计算了Ce3 的浓度。XRD和AFM分析表明，薄膜经空气中高温退火后，形成了立方体CaF2型小晶粒，晶粒大小明显依赖于退火条件和膜厚。     

退火处理对TiO2薄膜结构和透射的影响

在常温下,采用射频反应磁控溅射方法在不同溅射功率下于K9双面抛光玻璃基底上制备二氧化钛薄膜.将制备的样品进行450℃退火6h热处理.利用X射线衍射仪(XRD)对比分析了退火前后薄膜的微观结构,采用光栅光谱仪测试了退火前后薄膜样品的透射谱.实验结果表明,退火前薄膜样品是非晶态,退火后薄膜晶化为晶态,但不同溅射功率下制备的薄膜结晶取向有差异;退火热处理对薄膜的折射率有一定影响,表现为退火前后透射谱偏移.     

Non-stoichiometric NiZn ferrite by sol-gel processing

Non-stoichiometric Ni_0.5Zn_0.5Fe_2−xO_4−3/2x ferrites over a wide range of x = 0∼0.8 are synthesized by a sol-gel processing. Phase evolution, crystal structure and crystallite size of spinel ferrites are dependent on annealing temperature and the amount of Fe deficiency. The crystallite size of spinel increases with annealing temperature and grows faster in stoichiometric ferrites than that of non-stoichiometric. Fe deficiency results in the partial reduction of spinel ferrite to zincite ZnO. XRD indicates that the crystallization temperature of ZnO is increased to about 700 °C. Zincite reduces the number of ferrite crystallites and disfavors the growth of spinel ferrites. The lattice parameters decrease with Fe deficiency and are insensitive to the variation in composition in the samples annealed at lower temperature due to the segregation of ZnO and lattice expansion in the ultrafine crystallites.     

Microstructure modification of amorphous titanium oxide thin films during annealing treatment

Thin films of titanium oxide have been deposited on (100) silicon wafers and on quartz substrates by reactive r.f. magnetron sputtering from a 99.6% pure Titanium target. Amorphous and overoxidised coatings (TiO_2.2) have been obtained from this technique. The influence of the post-deposition annealing between 300 °C and 1100 °C on the structural and optical properties and on the surface morphology has been investigated. The results of X-ray diffraction showed that films annealed from 300 to 500 °C have an anatase crystalline structure whereas those annealed at 1100 °C have a rutile crystalline structure. Optical analyses showed that UV-Vis transmission spectra are strongly modified by the annealing temperature and refractive index of TiO_x layers also changes. Atomic force microscopy measurements corroborate optical and structural analyses and showed that the surface of the coatings can have various appearances and morphologies for the annealing temperatures investigated.     

LaNi5合金膜退火后的表面结构和氢敏特性

通过在空气中退火来改善由磁控溅射方法制备的LaNi_5合金膜的表面结构,使其具有在室温下吸放氢的能力。借助原子力显微镜、X射线衍射和X射线光电子能谱,分析了LaNi_5合金膜退火前后的形貌、结构和表层成分。结果表明:在空气中退火后,LaNi_5合金膜比表面积增加,并在其表层形成了La_2O_3-Ni的表层结构。氢敏测试结果显示,在空气中退火的样品不需要在高压纯氢中活化,在室温下即对氢气响应,说明该合金膜可以作为氢气传感器的敏感层。     

Surface nucleated crystallization in Ge15Te80As5 semiconducting glasses

The crystalline morphology of electrically conductive surface layers in thermally annealed bulk samples of Ge₁₅Te₈₀As₅ glass has been studied using a scanning electron microscope. Results confirm previous suggestions that crystallization is surface nucleated. Two regions of different crystalline morphology are observed and result from a two-stage crystallization process. Selected-area electron diffraction on extracted particles was used to identify the crystalline phases. The crystallites near the inner glassy material are Te, the first phase to segregate upon annealing. The crystalline material near the sample surface is more dense and contains two phases: GeTe (second-stage crystallization product) and crystalline Te. Energy Dispersive X-Ray Analysis with spacial resolution of 2–3 μm and accuracy of ±10% has shown that the “average” composition is the same for these crystalline regions and for the glassy material.     

Atomic force microscopy study on the anatase crystallization of long term stored Al2O3-TiO2-SiO2 coatings on glass

Atomic force microscopy was used to study the surface morphology of sol-gel derived Al₂O₃-TiO₂-SiO₂ coatings on microscope glasses. The coatings freshly annealed at 500°C for 1 h were homogeneous on a nanoscale and showed typical glass pattern. After 10-month storage in air either before or after annealing, tetragonal-like crystallites were observed in coatings. The effects of chemical compositions and the storage process on the surface topography and the crystallization of anatase were studied and discussed in combination with the XRD results of corresponding annealed gels.     

Effect of pH on crystallization of sputtered hydroxyapatite film under hydrothermal conditions at low temperature

Hydroxyapatite (HA) was coated onto titanium substrates using radio frequency sputtering, and the as-sputtered films were placed under hydrothermal conditions in distilled water solutions at pH 5.0, 7.0 and 9.0 and 110°C. The crystallinity, the Ca/P ratio, thickness, and the surface of the films were observed using XRD, EDS, and SEM, respectively.The as-sputtered film was crystallized in distilled water at varying pH after the hydrothermal treatment, and the crystallinity of the film increased with treatment time. The HA crystal size increased with pH. At pH 5.0, β-TCP was produced as well as HA. The Ca/P ratio of the film decreased with increasing treatment, and the ratio at pH 9.0 was 1.74 after 48 h, while in pH 5.0 and 7.0 it was 1.63. After hydrothermal treatment, the film remnant ratio increased with pH, with 75.9, 82.4 and 91.7% of the film remaining after 48 h at pH 5.0, 7.0 and 9.0, respectively.     

Phase transformation and thermal stability of ZnSe QDs due to annealing: emergence of ZnO

In the present study ZnSe quantum dots (QDs) were synthesized by chemical co-precipitation method using mercaptoethanol as the capping agent. These nanostructures were characterized for structure and surface morphology by using X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and Fourier transform infrared spectrometry respectively. The average size of ZnSe quantum dots from XRD and HRTEM is found to be 4–5 nm having cubic crystalline phase. Effect of annealing temperature, which were determined as phase transformation temperatures (299 and 426 °C) using differential scanning calorimetry has been investigated for structural and thermal stability of QDs. The XRD of annealed samples at temperatures 325 and 442 °C (slightly higher than the temperatures corresponding to two crystallization peaks in the DSC scan) have been carried out to find structural changes corresponding to these annealing temperatures. Sample annealed at 325 °C showed no change in the phase except improvement in intensity of peaks (crystallinity) whereas sample annealed at 442 °C showed transitions from cubic phase of ZnSe to ZnO and orthorhombic phases of ZnSeO₄, ZnSeO₃. Emergence of ZnO peaks in the XRD pattern of annealed samples have been further verified by Raman spectroscopy of the annealed samples. Besides this crystallization kinetics of ZnSe quantum dots has been employed to determine activation energies of these transitions due to oxidation by employing Kissinger, Augis Bennett and Ozawa’s models. Higher activation energy of crystallization corresponding to first crystallization peak shows that the cubic phase is more thermally stable.     

离子束溅射铜钨薄膜的结构

为了进一步探讨离子束溅射铜钨薄膜的结构,在铁片上离子束溅射铜钨薄膜,研究了轰击离子束能量及低能辅助轰击方式对薄膜相结构和厚度的影响.结果表明:随轰击铜靶离子束能量增加,钨由近似非晶亚稳态转变成晶态;由于溅射粒子落到基片前的反射效应,薄膜中间比边缘薄,且随轰击铜靶离子束能量增加,薄膜变薄到一定程度时开始增厚;当使用低能辅...     

Influence of oxygen in the deposition and annealing atmosphere on the characteristics of ITO thin films prepared by sputtering at room temperature

Indium tin oxide (ITO) thin films have been grown onto glass substrates by sputtering at room temperature with various controlled oxygen and argon ratios used as reactive and sputter gases, respectively. After deposition, the samples have been annealed at 350 °C in the same sputtering chamber in vacuum or in air. The structure, morphology and electro-optical characteristics of the ITO coatings have been analyzed as a function of the oxygen added during deposition and of the annealing atmosphere by X-ray diffraction, atomic force microscopy, four points electrical measurements and spectrophotometry. It has been found that the as-deposited amorphous samples crystallize in the cubic structure by annealing. The optical transmittance and the electrical resistance decrease when the oxygen content in the deposition and the annealing atmosphere is reduced.     

Polycrystalline growth and recrystallization processes in sputtered ITO thin films

Indium tin oxide (ITO) thin films with various thicknesses from 170 to 700 nm have been grown onto unheated glass substrates by sputtering from ceramic target, and subsequently annealed in vacuum at temperatures ranging from 250 to 350 °C. The structure, morphology and electro-optical characteristics of the ITO samples have been analyzed by X-ray diffraction, atomic force microscopy, four-point electrical measurements and spectrophotometry. Polycrystalline ITO growth has been found varying with film thickness. The thickness also determined the recrystallization achievable by annealing and the electro-optical thin film properties.     

Structural and surface properties of TiO2 thin films doped with neodymium deposited by reactive magnetron sputtering

Thin films were deposited using modified, high energy magnetron sputtering method from Ti-Nd mosaic targets. The amount of neodymium dopant incorporated into two sets of thin films was estimated to be 0.8 and 8.5 at.%, by means of energy dispersive spectroscopy. On the basis of x-ray diffraction method, the type of crystalline structure and crystallites size were evaluated directly after the deposition process and after additional post-process annealing at 800 °C temperature. The influence of annealing on the surface properties was evaluated with the aid of atomic force microscopy. Uniformity of the dopant distribution in titanium dioxide matrix was examined with the aid of secondary ion mass spectroscopy. Additionally, using atomic force microscope, diversification and roughness of the surface was determined. Chemical bonds energy at the surface of TiO₂:Nd thin films was investigated by x-ray photoelectron spectroscopy method. Wettability measurements were performed to determine contact angles, critical surface tensions and surface free energy of prepared coatings. On the basis of performed investigations it was found, that both factors, the amount of neodymium dopant and the post-process annealing, fundamentally influenced the physicochemical properties of prepared thin films.