Influence of binding layer on the reflective performance of a Au film in vacuum ultraviolet wavelength region

We investigate the influence of the binding layer on the reflectance of a Au film in vacuum ultraviolet (VUV) wavelength region theoretically and experimentally. The reflectance of Au films on quartz glass substrates with an approximately 2 nm binding layer of Ti, Cr, and Ir are estimated and fabricated. Their reflectance in the 115-140 nm wavelength region are measured continuously by the reflectometer located in the National Synchroton Radiation Laboratory. The testing results show that the addition of the binding layer indeed greatly enhances the interfacial adhesion of the Au layer to the quartz glass substrate, but it also exerts a considerably adverse impact on the reflectance of the Au layer in VUV wavelength region. In near normal incidence, the reflectance of the Au layer with a 2 nm thick binding layer is less than 20%, approximately 5% lower than those without the binding layer. The material used for the binding layer has little impact on the reflectance if this layer is thin enough.     

Investigation of the some physical properties of Ge-doped ZnO thin films deposited by thermionic vacuum arc technique

We exhibit the first nano-crystalline Ge–ZnO thin films deposited on glass and PET substrates by a thermionic vacuum arc technique. The effect of Ge doping on the structural, morphological and optical properties of ZnO:Ge films were investigated. An X-ray diffraction (XRD), atomic force microscopy, field emission scanning electron microscopy (FESEM) and UV–Vis spectrophotometer were used for the analysis. XRD patterns show the polycrystalline structure of the films in the range of 20°–80°. The roughness value for the ZnO:Ge on PET substrate was increased due to agglomeration of the grains. The results are in a good agreement with the FESEM images. Using Filmetrics F20 tool, the thickness values of the deposited thin films were obtained as 60 and 80 nm on glass and PET substrates, respectively. The optical properties of the films such as transmittance, absorbance, refractive index, and reflectance were determined. The band gap values were obtained as to be 3.43 and 3.38 eV glass and PET substrates, respectively. It was found that band gap variation of ZnO is very small with Ge doping.     

Oxygen-ion-assisted deposition of thin gold films

Thin gold films have been deposited on glass and silicon substrates using ion-assisted deposition techniques. The adhesion of the films to the substrates is assessed by a scratch test. Deposition assisted by 100 eV-1 keV oxygen ions yields highly adhesive films that can only be removed by damaging the substrate. Argon and hydrogen ions produce films with relatively poor adhesion. The results show that the reflectance of oxygen-assisted films is reduced by trapping of the oxygen in the gold but no bulk chemical or structural changes are detected. It is proposed that a thin stable layer of gold oxide is formed during film growth and diffuses into the substrate, providing a strong bond for subsequent film deposition. Highly adhesive films with bulk optical properties are deposited on glass and silicon using oxygen-ion assistance only to the point of continuous film formation.     

Corrosion resistance and microstructure of stainless steel modified by pulsed high energy density plasma

Pulsed high energy density plasma has been used to deposit aluminum nitride films on the surface of the 1Cr18Ni9Ti stainless steel (0.1% C, 18% Cr, 9% Ni, 0.8% Ti). The formed films are composed of nanocrystalline-structured aluminum nitride phase, whose crystal sizes are about 10 nm. Transition areas are formed across the film to the substrate and strengthen the adhesion between them. The nanocrystalline-structured aluminum nitride films contribute to the improvement of the corrosion resistance of the modified stainless steel, whose corrosion rate has been reduced by about ten times compared with that of the unmodified stainless steel.     

Highly transparent conductive and near-infrared reflective ZnO:Al thin films

Al-doped ZnO (AZO) thin films have been prepared on glass substrates by pulsed laser deposition. The structural, optical, and electrical properties were strongly dependent on the growth temperatures. The lowest resistivity of 4.5 × 10⁻⁴ Ωcm was obtained at an optimized temperature of 350 °C. The AZO films deposited at 350 °C also had the high optical transmittance above 87% in the visible range and the low transmittance (<15% at 1500 nm) and high reflectance (∼50% at 2000 nm) in the near-IR region. The good IR-reflective properties of ZnO:Al films show that they are promising for near-IR reflecting mirrors and heat reflectors.     

磁控共溅射Ni3 Al合金薄膜的微观结构及电阻特性

研究了室温下采用直流磁控共溅射法在抛光玻璃和Si基底上沉积Ni3Al合金薄膜的制备工艺、微观结构和电阻特性.采用SEM、EDX、AFM、TEM等测试分析了不同基底、溅射功率、工作气压等因素对薄膜微观结构、成分比和电阻特性的影响.结果表明:采用大功率混合溅射可以得到多晶态Ni3Al纳米合金薄膜,且呈多层岛状生长.所得薄膜具有良好的导电性,与玻璃相比,在Si基底上的薄膜表面光滑平整,晶粒更小,电阻率略大.然而随着厚度的减小,薄膜的电阻率增加迅速,发生金属向绝缘体过渡的相变,而厚度较大时这种现象不明显,这表明Ni3Al薄膜相变与厚度及晶格中氧含量有关.     

A facile UV-curing method for the preparation of transparent and conductive carbon nanotube hybrid films

A new method for preparing flexible, transparent, and conductive multiwalled carbon nanotube (MWCNT) hybrid films with scratch resistance through a facile UV-curing method is described herein. UV-curable urethane oligomers were used as the binder between the MWCNTs and the plastic substrates. The transparency and sheet resistance of MWCNT thin films can be easily tailored by controlling the number of bar coaters. Composite films with different binder ratios were prepared to evaluate and optimize the surface abrasion resistance and adhesion parameter. Two types of MWCNT films, those with a 56% (with a 586 komega/sq sheet resistance) and a 78% transmittance (with a 22 Momega/sq sheet resistance) were obtained using the UV-curable resin, and the conductive films showed distinguished abrasion resistance and good adhesion.     

Lattice distortion energy spectra of as-grown bismuth thin films and their thickness dependence

Bismuth thin films of various thicknesses between 15 nm and 350 nm were vacuum deposited at room temperature on to glass substrates, immediately after which they were twice heat treated at a uniform rate. During the heat treatment, the resistance changes were monitored and, using these data, the initial lattice distortion energy spectra of as-grown bismuth thin films have been evaluated. It is found that the defects have preferential activation energy values around 1.06 eV, 1.14 eV and 1.32 ev. It is also found that F ₀ (E) dE oscillates with thickness, which is attributed to the quantum size effect.     

Abrasion of thin films deposited onto glass by the Taber test

The mechanism of abrasion of sputtered metal nitride thin films on glass by the Taber abrasion test and the effects of mechanical and tribological properties of thin films on Taber abrasion were investigated. The abrasion occurred in a peeling mode: the film was peeled off the substrate and the peeled area increased with increasing number of Taber abrading cycles. The peel rate per Taber cycle, a quantitative measure to represent the abrasion resistance of the thin films, was small in the film with greater adhesion strength, higher hardness and lower frictional resistance of the surface. The effect of these properties on the peel rate was represented with a mathematical equation of exponential form. The peel rate was found to vary most sensitively with the hardness.     

Correlation between electrical properties and AES concentration-depth profiles of NiCr thin films

Concentration-depth profiles of NiCr films about 1000 Å thick were determined by Auger electron spectroscopy (AES) combined with argon ion sputtering. Three different films on optically flat polished glass substrates were investigated: a Cr sublimation layer, an evaporated layer consisting of a Cr base layer and a top layer of Ni (of overall composition Ni:Cr 80:20 wt.%) and an evaporation layer produced from an NiCr 80:20 wt.% alloy. The sheet resistance, temperature coefficient of resistance and contact resistance were measured and are discussed in terms of the elemental distribution within the films.     

Optical switching properties of Pd--Ni thin-film top-capped switchable mirrors

Switchable mirrors based on magnesium--nickel alloy thin films capped with catalytic Pd--Ni alloy thin films were prepared by a DC magnetron sputtering method. Their composition, structure and surface morphology were studied by XPS, XRD and AFM. Herein, the optical switching properties and durability of the switchable mirrors were investigated by varying the Ni content in the Pd--Ni alloys. Comparing pure Pd catalyst with Pd--Ni top-capped switchable mirrors, the latter show better hydrogenation and dehydrogenation kinetics, and the speed of hydrogen desorption is obviously improved with increasing Ni content in the Pd--Ni alloy. The Pd--Ni capped switchable mirrors also have better optical switching durability. The catalytic Pd layer with the addition of Ni does not influence the transmittance (hydride state) and reflectance (metallic state) of the switchable mirrors. In addition, replacing Pd with Pd--Ni alloy decreases the cost of the switchable mirrors: employing nickel in the alloy Pd_89.2Ni_10.8 can save about 11% use of Pd. Therefore, the Pd--Ni alloy can provide a cheaper catalytic thin film, and it is expected to have applications in energy-saving windows, hydrogen sensors and hydrogen storage materials.     

Silver-doped germanium sulphide glass channel waveguides fabricated by chemical vapour deposition and photo-dissolution process

Germanium sulphide glass thin films have been fabricated by chemical vapour deposition directly on commercial glass substrates. Silver (Ag)-doped channel waveguide structures were then prepared in a three step process, first channels were patterned in photo-resist, next a Ag thin film was deposited on the patterned waveguide by thermal evaporation, and finally the silver ions were doped into germanium sulphide glass by a photo-dissolution process. The refractive index of germanium sulphide increased by about 0.02 through the photo-dissolution process. The loss of the channel waveguides measured at 632.8 nm was 0.63 ± 0.05 dB/cm.     

Hochreflektierende Beschichtungen auf Kunststoffoptiken

Metallized polymer substrates offering highest reflectance are not yet state of the art. Coating organic substrate materials is still a task that is connected with multiple problems. Insufficient adhesion of coatings on polymer substrates represents one of the main difficulties. We could show by experiment that aluminium and silver layers indicate good coating adhesion on many different polymers if they are deposited by vacuum evaporation considering certain process parameters. High reflectance values and a good climatic stability of the metal coated polymer parts are other important challenges to plastic mirrors. By performing roughness measurements on the different polymer samples and by comparing reflection values obtained after coating these samples the impact of the polymers surface quality on the reflectance after metal coating has been investigated. Particularly high reflectance above 97% was realized with a protected silver mirror as well as with dielectric enhanced aluminium. Applying these layer systems excellent reflection properties has been obtained on several plastic substrates comparable to those on glass mirrors. Furthermore the dielectric layers used for reflection enhancement showed the ability to protect the aluminium coating against climatic influences.     

Inkjet printing of conductive Ag lines and their electrical and mechanical characterization

This paper aims to investigate the effects of the substrate, the printed line thickness and the sintering temperature on the electrical resistivity, Young's modulus and hardness of inkjet-printed Ag thin films. Electrical resistivity was determined from the four-point method and Young's modulus and hardness were evaluated from nanoindentation test. Several models for evaluating Young's modulus and hardness were used and compared to account for the influence of substrates. It is noted that Ag lines on glass have higher resistance and resistivity than those on polyimide (PI) since Ag lines on glass and PI have tensile and compressive residual thermal stresses, respectively, due to the difference of coefficient of thermal expansion between Ag lines and substrates. Young's modulus of Ag films on glass can be predicted by the modified King and Bec models considering the substrate effect, but these models offer unstable results for Ag films on PI. Young's modulus and hardness of Ag films increase with the sintering temperature, and they are little affected by the film thickness when fully sintered.     

Influence of pH on ZnO nanocrystalline thin films prepared by sol–gel dip coating method

ZnO nanocrystalline thin films have been prepared on glass substrates by sol?Cgel dip coating method. ZnO thin films have been coated at room temperature and at four different pH values of 4, 6, 8 and 10. The X-ray diffraction pattern showed that ZnO nanocrystalline thin films are of hexagonal structure and the grain size was found to be in the range of 25?C45?nm. Scanning electron microscopic images show that the surface morphology improves with increase of pH values. TEM analysis reveals formation of ZnO nanocrystalline with an average grain size of 44?nm. The compositional analysis results show that Zn and O are present in the sample. Optical band studies show that the films are highly transparent and exhibit a direct bandgap. The bandgap has been found to lie in the range of 3 $\boldsymbol\cdot$ 14?C3 $\boldsymbol\cdot$ 32?eV depending on pH suggesting the formation of ZnO nanocrystalline thin films.     

Measurement of adhesion of oxides grown on nickel and nickel alloys

Abstract

The adhesion of thin ceramic films to metal substrates is an important issue in a wide variety of technological areas; one of which is the corrosion of metal alloys at high temperature. Consequently, there is great interest in exploring the measurement of adhesion between ceramic films and metal substrates and the factors that control such adhesion. In this study, five methods for assessing the adhesion of thermally grown oxide scales to their substrates have been evaluated to establish their relative usefulness. Simple, well characterised model oxidation systems (high purity nickel, Ni–0·1 wt-%Cr, and Ni–0·1 wt-%Al alloys) have been used. The experiments showed that practical adhesion was measured most successfully using a double bending beam configuration and quantified in terms of the normal applied stress for catastrophic interfacial failure. Although the more convenient standard scratch test gives only semiquantitative results, these are nevertheless useful for comparisons within a given system. None of the techniques was capable of measuring the fracture toughness of the interface. The degree of practical adhesion of the oxide scales was found to decrease in the substrate order: high purity nickel >Ni–0·1Al>Ni–0·1Cr. The practical adhesion to the two alloys was sensitive to oxide thickness and there is a critical thickness (about 1·7 μm for Ni–0·1Cr and 4·8 μm for Ni–0·1Al) above which the practical adhesion is very low. This critical condition is probably the result of relaxation of residual compressive stress in the oxide by buckling of the scale.

MST/1467     

溶胶-凝胶法制备Ge/SiO2微晶复合薄膜

采用Ｓｏｌ－ｇｅｌ方法制备了ＧｅＯ２－ＳｉＯ２复合薄膜,并用Ｈ２／Ｎ２还原使得ＧｅＯ２转变成Ｇｅ微晶而镶嵌在ＳｉＯ２的玻璃网格中,其平均晶粒尺寸小于４ｎｍ 。随着热处理时间的增加,２４０ｎｍ 处吸收峰的强度随之增大,并且其吸收边产生红移,说明Ｇｅ 微晶的含量及晶粒尺寸都在增大     

Novel IV-Group Based Diluted Magnetic Semiconductor: Cr<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>Ge<Subscript>1−</Subscript><Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>

Cr _x Ge_{1? x} (x ～ 0.08) films were grown on GaAs (001) and Ge (001) substrates using molecular beam epitaxy (MBE) method, and their magnetic and transport properties have been studied in the temperature range between 1.8 and 300 K. All of the films exhibited weak paramagnetic behavior. Transport measurements showed that magnetoresistance ratio and the anomalous Hall resistance depend on the Cr concentration x and the kinds of substrate.     

The substrate effect on Ge doped GaN thin films coated by thermionic vacuum arc

This study focuses on characterization and understanding of the substrate effect on Ge doped GaN thin films coated onto transparent substrates. The produced films were deposited onto unheated glass and unheated polyethylene terephthalate by using thermionic vacuum arc technique. Gallium nitride and germanium pellets were used in the thin film production. Reflectance, refractive index and thicknesses of Ge doped GaN thin films were measured by optical interferometer using Cauchy model for fitting. The transmittances were determined in the wavelength range between 200 and 1000 nm by using UV–Vis double beam spectrophotometer. The optical Tauc method was used to determine the band gap energies of produced thin films. Surface morphologies of produced thin films were characterized by atomic force microscopy and also field emission scanning electron microscopy. In conclusion, the substrate effect on the optical and morphological properties of the produced thin films was observed.     

Optical properties of silver sulphide thin films formed on evaporated Ag by a simple sulphurization method

Silver sulphide (Ag₂S) thin films were grown on the surface of silver films (Ag) deposited on glass substrate by using a simple chemical sulphurization method. According to X-ray diffraction analysis, the Ag₂S thin films display low intensity peaks at 34.48°, 36.56°, and 44.28°, corresponding to diffraction from (100), (112) and (103) planes of the acanthite phase (monoclinic). A model of the type Ag₂S/Ag/glass was deduced from spectroscopic ellipsometric measurements. Also, the optical constants (n, k) of the system were determined. Furthermore, the optical properties as solar selective absorber for collector applications were assessed. The optical reflectance of the Ag₂S/Ag thin film systems exhibits the expected behavior for an ideal selective absorber, showing a low reflectance in the wavelength range below 2 µm and a high reflectance for wavelengths higher than that value. An absorptance about 70% and an emittance about 3% or less were calculated for several samples.