Prefabrication of two-dimensional Ni–W/TiN films on oil-gas X52 steels by pulse electrodeposition

The main aim of this investigation was to prefabricate two-dimensional Ni–W/TiN films on oil-gas X52 steel substrates via pulse electrodeposition (PE). The influences of the TiN content in the bath on the surface morphology, nano-hardness, wear, and corrosion properties of the films were also discussed. The results indicated that the TiN particle size was only ～33 nm in 8 g/L TiN electrolyte, which was ～2.4 times less than that of TiN in 16 g/L solution. The Ni–W/8TiN film exhibited a uniform, smooth surface, and the depression depth and protrusion height were 45.3 nm and 81.7 nm, respectively. Three diffraction peaks at 43.72, 50.78, and 75.26° in the Ni–W/4TiN film emerged as the sharpest and narrowest peaks among the four films. Three XPS peaks for the Ni 2p_3/2 were present at 852.13, 856.35, and 861.87 eV in the Ni–W/8TiN film, corresponding to Ni, Ni²⁺ (Ni(OH)₂), Ni³⁺ (NiOOH) species. Besides, the XPS peak of W 4f_7/2, which located at 33.85 eV belonged to elemental W. The Ni–W/8TiN film had the lowest wear depth and width at 32.1 μm and 5.7 mm, respectively. Only some narrow and shallow scratches were found on the Ni–W/8TiN film surface, showing its outstanding tribological properties among the films tested. In addition, the Ni–W/4TiN film showed the highest mean frictional coefficient of 0.73, which was ～1.6 times more than that of the Ni–W/8TiN film.     

XPS calibration study of thin‐film nickel silicides

This paper presents a systematic X‐ray photoelectron spectroscopy (XPS)study of the Ni silicides Ni₃Si, Ni₃₁Si₁₂, Ni₂Si, NiSi and NiSi₂ produced by annealing of sputtered thin films. The in situ XPS study focuses on both the core level peaks and Auger peaks. The peak positions, shapes, satellites as well as Auger parameters are compared for different silicides. The factors that influence the Ni core level peak shifts are discussed. The Ni 2p_3/2 peak shape and satellites are correlated with the valence band structure. The effect of argon ion etching on surface composition and chemical states is also investigated. Copyright © 2009 John Wiley & Sons, Ltd.     

The effects of oxygen concentration on ultraviolet luminescence of ZnO films by sol–gel technology and annealing

ZnO thin films were successfully deposited on SiO₂/Si substrate using the sol–gel technique and annealed in various annealing atmospheres at 900 °C by rapid thermal annealing (RTA). X-ray diffraction revealed the (002) texture of ZnO thin films. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed that the grains of the ZnO thin film were enlarged and its surface was smoothed upon annealing in oxygen. PL measurement revealed two ultraviolet (UV) luminescence bands at 375 and 380 nm. The intensity of the emission peak at 380 nm became stronger as the concentration of oxygen in the annealing atmosphere increased. The X-ray photoelectron spectrum (XPS) demonstrated that a more stoichiometric ZnO thin film was obtained upon annealing in oxygen and more excitons were generated from the radiative recombination carriers consistently. Additionally, the UV intensity increased with the thickness of ZnO thin film.     

Effect of Pt loading on the photocatalytic reactivity of titanium oxide thin films prepared by ion engineering techniques

Platinum-loaded titanium oxide thin-film photocatalysts were prepared by using an ionized cluster beam (ICB) deposition method and a RF magnetron sputtering (RF-MS) deposition method as dry processes. From the results of the photocatalytic oxidation of acetaldehyde with O₂ under UV light irradiation, small amounts of Pt loading (less than 10 nm film thickness) were found to dramatically enhance the photocatalytic reactivity. However, when TiO₂ thin films were loaded with relatively larger amounts of Pt (more than 30 nm as the film thickness), the photocatalytic reactivity became lower than for the pure TiO₂ thin films. Moreover, investigations of the ratio of Pt loaded onto the surface of the thin film catalysts by XPS measurements revealed that the small amounts of Pt loaded exist as very small clusters working to efficiently enhance the charge separation, whereas, large amounts of Pt covers the entire surface of the TiO₂ thin films, resulting in a decrease of the photocatalytic reactivity.     

Bioactivity and mechanical properties of nickel‐incorporated hydrogenated carbon nanocomposite thin films

In this paper, the influence of nickel incorporation on the mechanical properties and the in vitro bioactivity of hydrogenated carbon thin films were investigated in detail. Amorphous hydrogenated carbon (a‐C:H) and nickel‐incorporated hydrogenated carbon (Ni/a‐C:H) thin films were deposited onto the Si substrates by using reactive biased target ion beam deposition technique. The films' chemical composition, surface roughness, microstructure and mechanical properties were investigated by using XPS, AFM, TEM, nanoindentation and nanoscratch test, respectively. XPS results have shown that the film surface is mainly composed of nickel, nickel oxide and nickel hydroxide, whereas at the core is nickel carbide (Ni₃C) only. The presence of Ni₃C has increased the sp² carbon content and as a result, the mechanical hardness of the film was decreased. However, Ni/a‐C:H films shows very low friction coefficient with higher scratch‐resistance behavior than that of pure a‐C:H film. In addition, in vitro bioactivity study has confirmed that it is possible to grow dense bone‐like apatite layer on Ni/a‐C:H films. Thus, the results have indicated the suitability of the films for bone‐related implant coating applications. Copyright © 2011 John Wiley & Sons, Ltd.     

Production and characterization of nitrided CVD-SiC films

Silicon Carbide (SiC) and SiC with free silicon [SiC(Si)] thin films were prepared by chemical vapor deposition (CVD) using a CH₃SiCl₃-H₂-Ar gas mixture at a temperature of 1223 K. Afterwards these layers were gas nitrided in an ammonia-hydrogen-argon mixture at 1273 K. The solid product is an extremely thin film of silicon nitride on SiC or SiC(Si)-basic layers. These ultra thin silicon nitride films were investigated by glow discharge optical spectroscopy (GDOS) and x-ray photoelectron spectroscopy (XPS). The thickness of the layers was determined to a maximum value of 30 nm.Dedicated to Professor Dr. rer. nat. Dr. h.c. Hubertus Nickel on the occasion of his 65th birthday     

Interaction of O2, CO and CO2 with Co films

Metastable impact electron spectroscopy (MIES), ultraviolet photoelectron spectroscopy (UPS(HeI)) and x‐ray photoelectron spectroscopy (XPS) were applied to study the interaction of O₂, CO and CO₂ with Co films at room temperature. The films were produced on Si(100) surfaces under the in situ control of MIES, UPS and scanning tunnelling microscopy (STM). For O₂, dissociative adsorption takes place initially and then incorporation of oxygen starts at exposures of ～5 L. Comparison of the MIES and UPS spectra with those published for CoO shows that near‐stoichiometric CoO films can be obtained by co‐deposition of Co and O₂. The CO is adsorbed molecularly up to a maximum coverage of ～0.6 monolayer, with the C‐end pointing towards the surface. The CO₂ adsorption is dissociative, resulting in the formation of Co–CO bonds at the surface. The resulting oxygen atoms are mostly incorporated into the Co layer. For all studied molecules the interaction with Co is similar to that with Ni. Copyright © 2005 John Wiley & Sons, Ltd.     

Thick lanthanum zirconate buffer layers from water-based precursor solutions on Ni-5%W substrates

In this work, water-based precursor solutions suitable for dip-coating of thick La₂Zr₂O₇ (LZO) buffer layers for coated conductors on Ni-5%W substrates were developed. The solutions were prepared based on chelate chemistry using water as the main solvent. The effect of polymer addition on the maximum crack-free thickness of the deposited films was investigated. This novel solution preparation method revealed the possibility to grow single, crack-free layers with thicknesses ranging 100–280 nm with good crystallinity and an in-plane grain misalignment with average FWHM of 6.55°. TEM studies illustrated the presence of nanovoids, typical for CSD–LZO films annealed under Ar-5%H₂ gas flow. The appropriate buffer layer action of the film in preventing the Ni diffusion was studied using XPS. It was found that the Ni diffusion was restricted to the first 30 nm of a 140 nm thick film. The surface texture of the film was improved using a seed layer.     

改性中孔分子筛SBA-16薄膜的合成及表征

在酸性条件下, 以导电玻璃(ITO)为基底合成了SBA-16分子筛膜. 所制备的SBA-16膜孔径均匀, 具有体心立方结构(属于Im3m空间群), SBA-16膜的晶胞参数为18.6 nm. TEM, SEM和XRD等技术研究表明, 加入少量的AlCl₃盐于形成膜的母液并且采用RSiX₃对导电玻璃基底进行处理, 能够明显改善SBA-16膜的连续性而不影响孔结构. 红外(FTIR)研究结果表明, SBA-16膜的表面硅羟基和结晶水很少, 膜很稳定. XPS研究表明, 加入少量MnCl₂对SBA-16膜进行改性, 可以提高膜的导电性.     

Ultra‐thin SiO2 on Si VIII. Accuracy of method,linearity and attenuation lengths for XPS

In the study of ultra‐thin films (<10‐nm thick), there is a range of methods that can provide accurate measurements of differences in thickness. However, in a pilot study under the auspices of the Consultative Committee for Amount of Substance (CCQM), results for the archetypal system of SiO₂ on Si show that the methods have different offsets such that, at all thicknesses, positive or negative amounts in the range up to 1 nm may be observed between methods. All the methods studied give thicknesses that are greater than those measured by X‐ray photoelectron spectroscopy (XPS) by amounts between 0.2 nm and approximately 1 nm. Significant parts of these offsets, of other methods with respect to XPS, may be attributed to contaminations which increase the apparent thickness but that do not affect XPS. However, not all of these offsets can yet be explained at the 0.2 nm level. The remaining part of the offsets could be thought to have arisen either from the XPS or from the other methods. In this study, by measuring SiO₂ deposited in situ on amorphous Si by XPS it is shown that the XPS linearity is consistent with the previous estimate of ± 0.025 nm, down to fractions of a monolayer, with no significant offset and that, therefore, it is the offsets seen using other methods that need further study. Recent calculations of the film thickness dependence of the attenuation lengths (ALs) for this system, using NIST SESSA software, are not consistent with these data although earlier calculations are. This work shows that XPS, with the AL calibrated by one or more other methods that are valid for differences in thickness, can provide a traceable measurement of thickness in all laboratories. © Crown Copyright 2007. Reproduced with the permission of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd.     

Growth,characterization and interfacial reaction of magnetron sputtered Pt/CeO2 thin films on Si and Si3N4 substrates

Growth of magnetron sputtered Pt/CeO₂ thin films on Si and Si₃N₄ were characterized by X‐ray diffraction (XRD), field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM) and X‐ray photoelectron spectroscopy (XPS). Interaction of Pt/CeO₂ films with Si on Si and Si₃N₄ substrates was extensively investigated by XPS. XRD studies show that films are oriented preferentially to (200) direction of CeO₂. XPS results show that Pt is mainly present in +2 oxidation state in Pt/CeO₂/Si film, whereas Pt⁴⁺ predominates in Pt/CeO₂/Si₃N₄ film. Concentration of Pt⁴⁺ species is more than four times on Si₃N₄ substrate as compared with that on Si. Ce is present as both +4 and +3 oxidation states in Pt/CeO₂ films deposited on Si and Si₃N₄ substrates, but concentration of Ce³⁺ species is more in Pt/CeO₂/Si film. Interfacial reaction between CeO₂ and Si substrate is controlled in the presence of Pt. Pt/Ce concentration ratio decreases in Pt/CeO₂/Si₃N₄ film upon successive sputtering, whereas this ratio decreases initially and then increases in Pt/CeO₂/Si film. Copyright © 2015 John Wiley & Sons, Ltd.     

Structural properties of lithium thio-germanate thin film electrolytes grown by radio frequency sputtering

In this study, lithium thio-germanate thin film electrolytes have been successfully prepared by radio frequency (RF) magnetron sputtering deposition in Ar gas atmospheres. The targets for RF sputtering were prepared by milling and pressing appropriate amounts of the melt-quenched starting materials in the nLi(2)S + GeS(2) (n = 1, 2, and 3) binary system. Approximately 1 μm thin films were grown on Ni coated Si (Ni/Si) substrates and pressed CsI pellets using 50 W power and 25 mtorr (～3.3 Pa) Ar gas pressures to prepare samples for Raman and Infrared (IR) spectroscopy, respectively. To improve the adhesion between the silicon substrate and the thin film electrolyte, a sputtered Ni layer (～120 nm) was used. The surface morphologies and thickness of the thin films were determined by field emission scanning electron microscopy (FE-SEM). The structural properties of the starting materials, target materials, and the grown thin films were examined by X-ray diffraction (XRD), Raman, and IR spectroscopy.     

XPS Analysis of Lead Zirconate Titanate Thin Films Prepared Via a Sol-Gel Process

The crystalline phase and composition of sol-gel-derived lead zirconate titanate (PbZr _x Ti_{1 – x} O₃, PZT) thin films were determined by an X-ray photoelectron spectroscopic (XPS) data processing technique. As a result, it was proved that existence of the surface layer with several tens nm in thickness, of which the crystalline phase and composition were different from those of the inside of the thin films, was found. The newly developed XPS analytical technique is much applicable for the characterization of PZT thin film surface.     

SAW hydrogen gas sensor based on WO3 and Pd nanostructures

Bi-layer nanostructures of WO₃ (～100 nm and 150 nm) with a very thin film of palladium (Pd～10 nm) on the top, have been studied for hydrogen gas-sensing application at ～700C and medium hydrogen concentrations (1 – 4%) in air. The structures were obtained by vacuum deposition (first the WO₃ and then the Pd film) onto a LiNbO₃ Y- cut Z-propagating substrate and were tested by means of Surface Acoustic Wave method in a three channel delay line configuration. Very repeatable results have been observed for these two nanostructures with changes in frequency on the level of 500 to 1800 Hz for hydrogen concentration from 1 to 4 % in air. The absolute response value depends on the WO₃ film thickness and hydrogen gas concentration and is greater for the nanostructure with a thicker WO₃ film.     

气液界面法组装的Ni3(HITP)2电致变色薄膜及其性能

由于缺乏可控的成膜技术,三亚苯类金属有机框架(MOFs)材料的应用受到了限制。我们在气液界面组装了不同厚度的Ni₃(HITP)₂薄膜(HITP^3-=2,3,6,7,10,11-六亚氨基三亚苯),并将制备的薄膜转移到导电玻璃表面。利用X射线衍射(XRD)、场发射透射电子显微镜(FETEM)、场发射扫描电镜(FESEM)、X射线光电子能谱(XPS)和拉曼光谱对样品的晶体结构、微观形貌和元素组成进行表征,采用紫外可见分光光度计以及电化学工作站对Ni₃(HITP)₂薄膜的电化学和电致变色性能进行了研究和表征。结果表明,得益于Ni₃(HITP)₂电致变色薄膜的多孔结构和与电解液良好的接触,所得薄膜电极N-20具有较短的着色响应时间/褪色响应时间(0.6/0.7 s),且着色效率可达530 cm²·C^-1;而N-50具有较大的光调制范围(740 nm,70%)。     

Study on the Superhydrophilicity of the SiO2-TiO2 Thin Films Prepared by Sol-Gel Method at Room Temperature

Nanoscale SiO₂-TiO₂ composite thin films with the thickness of about 100 nm were prepared by sol-gel method at room temperature in air. The chemical states of the elements on the surface and near the surface were measured by XPS. The results showed that the Ti on/near the surface of the thin films existed not only as TiO₂ but also as Ti₂O₃. Part of the TiO₂ was changed to Ti₂O₃ after UV irradiation. The crystalline structure of the TiO₂ in the SiO₂-TiO₂ thin films was anatase with the crystallite size of 14–20 nm. It was found that the thin film prepared at room temperature in air has good superhydrophilic property and has strong adherence to the substrate.     

Nanoporous Ni3S2 Film on Ni Foam as Highly Efficient Electrocatalyst for Hydrogen Evolution in Acidic Electrolyte

In this work, nanoporous Ni₃S₂ film (Ni₃S₂/Ni) is in situ synthesized by direct sulfurization of Ni foam under a mild hydrothermal process. Surprisingly, it is found out that the obtained Ni₃S₂/Ni exhibits outstanding HER activity and excellent stability in acidic electrolyte. The structure and nature of the Ni₃S₂/Ni are analyzed with X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and field emission scanning electron microscope (FE-SEM). On Ni₃S₂/Ni, the onset potential is only ?6.23 mV (vs. RHE) while the large exchange current density is 790 µA cm^?2 and the Tafel slope is 62.47 mV dec^?1. The experimental results demonstrate the potential of Ni₃S₂/Ni for its replacement of Pt-based catalysts.

     

Comparative thickness measurements of SiO2/Si films for thicknesses less than 10 nm

We report on a comparative measurement of SiO₂/Si dielectric film thickness (t < 10 nm) using grazing‐incidence x‐ray photoelectron spectroscopy, neutron reflectometry and spectroscopic ellipsometry. Samples with nominal thicknesses of 3–7 nm were characterized by XPS with grazing‐incidence x‐rays at 1.8 keV, by cold neutron reflectometry (λ = 0.475 nm) and by spectroscopic ellipsometry over 1.5 eV < E < 6.0 eV. The results show good agreement between the ellipsometry and grazing‐incidence XPS, with slightly lower values for the neutron reflectometry. The role of surface contamination in each type of measurement is discussed. Published in 2004 by John Wiley & Sons, Ltd.     

Molecular dynamics simulation of surface segregation in a (110) B2-NiAl thin film

Surface segregation in (110) B2-NiAl film approximately 3 nm thick is investigated by using molecular dynamics simulation with a reliable embedded-atom potential. The simulation is performed for the stoichiometric composition at a temperature of 1500 K, just below the melting temperature of the film model. It is found that the (110) surface is structurally stable but develops adatoms, vacancies and antisites. The coverage of an adatom layer is estimated to be ～0.07 ML (monatomic layers) and it contains on average ～95% of Al atoms. The top (surface) and second (subsurface) layers of the (110) surface is the most enriched in Ni relative to the bulk composition. These layers contain on average ～51% of Ni atoms. The Ni fraction in the third and forth layers of the film is estimated as ～50.5%. The deeper layers have essentially the bulk composition. Vacancies in the film model are found only on the Ni sublattice. The vacancy concentration on the Ni sublattice in the top layer is ～7.5%. The second layer almost does not contain vacancies. The next layers have essentially the constant bulk vacancy composition which can be estimated as ～1.3-1.4%.     

总气压与Ar/O2流量比对直流对向靶磁控溅射TiO2薄膜光催化性能的影响

采用对向靶磁控溅射法在不同气压和Ar/O₂流量比条件下, 以氟化SnO₂ (FTO)导电玻璃为基底制备了多晶TiO₂薄膜. 台阶仪测量结果显示所制备TiO₂薄膜的平均厚度约为200 nm. 随着溅射气压的升高, TiO₂薄膜由锐钛矿与金红石混晶结构转变为纯锐钛矿结构. 分别采用场发射扫描电镜(FESEM)和原子力显微镜(AFM)分析了不同气压和Ar/O₂流量比对TiO₂薄膜表面形貌的影响, 结果显示TiO₂薄膜的表面粗糙度随溅射总气压和Ar/O₂流量比的增加而增大. 以初始浓度为100×10^-6 (体积分数)的异丙醇(IPA)气体为目标物检测所制备TiO₂薄膜的光催化性能, 并分析该气相光催化反应的机理, 在紫外照射条件下异丙醇先氧化为丙酮再被氧化为CO₂.当总溅射气压为2.0 Pa、Ar/O₂流量比为1:1时, 溅射所得TiO₂薄膜具备最优光催化活性并可在IPA降解反应中保持较高的催化活性和稳定性.