Effects of sputtering power and annealing temperature on surface roughness of gold films for high-reflectivity synchrotron radiation mirrors

Gold films deposited by direct current magnetron sputtering are used for synchrotron radiation optics. In this study, the microstructure and surface roughness of gold films were investigated for the purpose of developing high-reflectivity mirrors. The deposition process was first optimized. Films were fabricated at different sputtering powers (15, 40, 80, and 120 W) and characterized using grazing incidence X-ray reflectometry, X-ray diffraction, and atomic force microscopy. The results showed that all the films were highly textured, having a dominant Au (111) orientation, and the film deposited at 80 W had the lowest surface roughness. Subsequently, post-deposition annealing from 100 to 200℃ in a vacuum was performed on the films deposited at 80 W to investigate the effect of annealing on the microstructure and surface roughness of the films. The grain size, surface roughness, and their relationship were investigated as a function of annealing temperature. AFM and XRD results revealed that at annealing temperatures of 175 ℃ and below, microstructural change of the films was mainly manifested by the elimination of voids. At annealing temperatures higher than 175℃, grain coalescence occurred in addition to the void elimination, causing the surface roughness to increase.

New approach to fabricate nanoporous gold film

A simple preparation of ultrathin nanoporous gold film was described. Copper and gold were used to fabricate Cu-Au alloy films through vacuum deposition. The formation of nanoporous gold films from the alloy films involved thermal process and chemical etch by hydrochloric acid or by nitric acid. The free-standing nanoporous gold films have been analyzed by scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, X-ray photoelectron spectrometer （XPS） and surface-enhanced Raman scattering （SELLS）. R was noted that the nanoporous gold film etched by hydrochloric acid is uniform with a cover of fog-like moieties.

The determination of the thickness and the optical dispersion property of gold film using spectroscopy of a surface plasmon in the frequency domain

We propose to use wavelength modulation approach,i.e.,the spectroscopy of a surface plasmon in the frequency domain,to characterize the optical dispersion property of gold film.Using this method,we determine the dispersion relationship of gold film in a wavelength range from 537.12 nm to 905.52 nm,and our results accord well with the reported results by other authors.This method is particularly suited for studying the optical dispersion properties of thin metal films,because a series of dielectric constants over a wide spectral range can be determined simultaneously via only a single scan of the incident angle,thereby avoiding the repeated measurements required when using the angular modulation approach.

A high figure of merit localized surface plasmon sensor based on a gold nanograting on the top of a gold planar film

We investigate the sensitivity and figure of merit （FOM） of a localized surface plasmon （LSP） sensor with gold nanograting on the top of planar metallic film. The sensitivity of the localized surface plasmon sensor is 317 nm/RIU, and the FOM is predicted to be above 8, which is very high for a localized surface plasmon sensor. By employing the rigorous coupled-wave analysis （RCWA） method, we analyze the distribution of the magnetic field and find that the sensing property of our proposed system is attributed to the interactions between the localized surface plasmon around the gold nanostrips and the surface plasmon polarition on the surface of the gold planar metallic film. These findings are important for developing high FOM localized surface plasmon sensors.

Effects of annealing time on the structure, morphology, and stress of gold–chromium bilayer film

In this work, a 200-nm-thick gold film with a 10-nm-thick chromium layer used as an adhesive layer is fabricated on fused silica by the electron beam evaporation method. The effects of annealing time at 300℃ on the structure, morphology and stress of the film are studied. We find that chromium could diffuse to the surface of the film by formatting a solid solution with gold during annealing. Meanwhile, chromium is oxidized on the surface and diffused downward along the grain grooves in the gold film. The various operant mechanisms that change the residual stresses of gold films for different annealing times are discussed.

Gold Nanoparticulate Thin Films Fabricated by the Electrostatic Self-Assembly Process

Gold colloids were prepared by citrate-induced reduction of hydrogen tetrachloroaurale, and gold nanoparticles were electrostatically self-assembled with poly( diallyldimethylammonium chloride) into multi-layer thin films on si/icon and quartz substrates. The paniculate thin films were characterized by UV-vis spea-troscopy, surface, enhanced Raman scattering, atomic force microscopy and resistivity measurements. Due to the interparticle coupling between individual gold particles, an obvious collective particle plasmon resonance was ob-served on UV-vis spectra , and the particulate thin films exhibited a strong SERS effect. For multilayer thin films with a high particle coverage on substrates , resistivity of the order of 10-4 Ω·cm was yielded.

The spin Hall effect in single-crystalline gold thin films

The spin Hall effect has been investigated in 10-nm-thick epitaxial Au(001) single crystal films via H-pattern devices,whose minimum characteristic dimension is about 40 nm. By improving the film quality and optimizing the in-plane geometry parameters of the devices, we explicitly extract the spin Hall effect contribution from the ballistic and bypass contribution which were previously reported to be dominating the non-local voltage. Furthermore, we calculate a lower limit of the spin Hall angle of 0.08 at room temperature. Our results indicate that the giant spin Hall effect in Au thin films is dominated not by the interior defects scattering, but by the surface scattering. Besides, our results also provide an additional experimental method to determine the magnitude of spin Hall angle unambiguously.

Preparation and Characterization of Gold Thin Film Electrode Modified by Microbe

A novel method based on microbe modification has been employed to prepare gold thin film electrode. The preparation method is simple and the electrode obtained is stable and very sensitive in determining heavy metal ions. The quantitation limit of Cu2+ is 0.05 ng/mL.

Spectra of Plasmon Polaritons at Metal―Insulator Interfaces of a Nanosized Gold Film: Expansion into Components and Their Systematization

The spectral characteristics of surface plasmon resonance (SPR) in nanosized gold films were studied with method of internal reflection in the Kretschmann geometry. (For more information,please refer to the PDF.)

316L不锈钢磁控溅射镀玫瑰金膜层及其耐磨性

[目的]研究磁控溅射镀玫瑰金膜层的组成及耐磨性。[方法]以316L不锈钢为基材,采用磁控溅射技术在不同靶电流下制备玫瑰金膜层。通过扫描电子显微镜(SEM)、X射线衍射仪(XRD)和X射线光电子能谱仪(XPS)研究了膜层的表面形貌和组织结构,通过纳米压痕测试和摩擦磨损试验考察了膜层的显微硬度和耐磨性。[结果]随着靶电流从0.5 A增大到1.5 A,玫瑰金膜层的晶粒不断增大,显微硬度减小,耐磨性变差。不同靶电流下所得玫瑰金膜层均由Au^(0)、Cu^(0)和Au_(3)Cu构成,并且以Au_(3)Cu相的(111)和(222)晶面为主。[结论]本研究可为不锈钢表面磁控溅射镀玫瑰金工艺的实际应用提供参考。

抗镀金褪膜药水对封装基板镀层品质影响研究

研究A、B、C这3种不同体系褪膜药水对封装基板电镀镍金表面处理镀层和铜面的品质影响。通过研究发现:A系列会导致铜面污染异物,影响打线,出现铜面外观异色、金面外观异色等品质问题;B系列和C系列与干膜反应过程中,仅产生蓝色片状干膜屑,与验证板完全脱离,对验证板品质无影响。通过对褪膜反应原理和药水展开分析,猜测其为A系列褪膜药水中的有机碱与羧酸产生黏性物质沉淀,黏性物质反粘在验证板铜面,产生验证板铜面外观不易检出的透明异物。通过研究,改善现有产品抗镀金去膜后镀层外观和功能性问题,并为后续封装基板抗镀金干膜和褪膜药水组合搭配时,镀层产品品质影响的评价项目和方法提供参考。

Near-perfect fidelity polarization-encoded multilayer optical data storage based on aligned gold nanorods

Encoding information in light polarization is of great importance in facilitating optical data storage(ODS)for information security and data storage capacity escalation.However,despite recent advances in nanophotonic techniques vastly en-hancing the feasibility of applying polarization channels,the data fidelity in reconstructed bits has been constrained by severe crosstalks occurring between varied polarization angles during data recording and reading process,which gravely hindered the utilization of this technique in practice.In this paper,we demonstrate an ultra-low crosstalk polarization-en-coding multilayer ODS technique for high-fidelity data recording and retrieving by utilizing a nanofibre-based nanocom-posite film involving highly aligned gold nanorods(GNRs).With parallelizing the gold nanorods in the recording medium,the information carrier configuration minimizes miswriting and misreading possibilities for information input and output,respectively,compared with its randomly self-assembled counterparts.The enhanced data accuracy has significantly im-proved the bit recall fidelity that is quantified by a correlation coefficient higher than 0.99.It is anticipated that the demon-strated technique can facilitate the development of multiplexing ODS for a greener future.

Structure and internal stress of Au films deposited on SiO_2/Si(100) and mica by dc sputtering

Au films with a thickness of about 300 nm were deposited on SiO_2/Si(100) andmica substrates by dc sputtering. X-ray diffraction spectroscopy and field emission scanningelectron microscopy were used to analyze the structure and internal stress of the Au films. Thefirms grown on SiO_2/Si(100) show a preferential orientation of [111] in the growth direction.However the films grown on mica have mixture crystalline orientations of [111], [200], [220] and[311] in the growth direction and the orientations of [200] and [311] are slightly more than thoseof [111] and [220]. An internal stress in the films grown on SiO_2/Si(100) is tensile. For Au filmsgrown on mica the internal stresses in the [111]- and [311]-orientation grains are compressive whilethose in the [200]- and [220]-orientation grains are tensile. Au films grown SiO_2/Si(100) havesome very large grains with a size of about 400 nm and have a wider grain size distribution comparedwith those grown on mica.

Numerical study of optical trapping properties of nanoparticle on metallic film with periodic structure

Based on the three-dimensional dispersive finite difference time domain method and Maxwell stress tensor equation,the optical trapping properties of nanoparticle placed on the gold film with periodic circular holes are investigated numerically. Surface plasmon polaritons are excited on the metal-dielectric interface, with particular emphasis on the crucial role in tailoring the optical force acting on a nearby nanoparticle. Utilizing a first order corrected electromagnetic field components for a fundamental Gaussian beam, the incident beam is added into the calculation model of the proposed method. To obtain the detailed trapping properties of nanoparticle, the selected calculations on the effects of beam waist radius, sizes of nanoparticle and circular holes, distance between incident Gaussian beam and gold film, material of nanoparticle and polarization angles of incident wave are analyzed in detail to demonstrate that the optical-trapping force can be explained as a virtual spring which has a restoring force to perform positive and negative forces as a nanoparticle moves closer to or away from the centers of circular holes. The results of optical trapping properties of nanoparticle in the vicinity of the gold film could provide guidelines for further research on the optical system design and manipulation of arbitrary composite nanoparticles.

Fabrication of Au/SiO_(2) Nanocomposite Films by Self-Assembly Multilayer Method

Gold colloid was prepared by chemical reduction of hydrogen tetrachloroaurate, polyelectrolyte/gold nanoparticle/silica nanoparticie composite films were fabricated via an electrostatic self-assembly multilayer method, and composite films of gold nanoparticle dispersed in silica matrix were formed by heat-treating the polyelectrolyte/gold nanoparticle/silica nanoparticle composite films to eliminate the polyelectrolyte. The obtained composite films were investigated with UV-vis, TEM, AFM and XRD. The results show that the self-assembly multilayer method is a promising process to produce composite films of gold nanoparticle-dispersed in organic and/or inorganic matrixes.

Optical Absorption of Nano-Composite Thin Films of Au in Teflon

Nano-composite films of Au particles in Teflon were obtained by thermal vacuum deposition. The obtained films were characterized by the different shapes and dimensions of the inclusion particles. Absorption spectra of the films were measured in-situ. A model for the calculation of the optical properties of the nano-composite thin films with an inho-mogeneous distribution of the inclusions along the thickness of the film is proposed. Absorption properties of inclusions were analyzed by considering the local field interaction. The calculated absorption profiles are compared with the experimentally obtained absorption profiles. This comparison gives a possibility to draw conclusions about the concentration, shapes and shape distributions of the inclusion particles. For example, the films obtained by duration deposition are characterized by inclusions having the shape of prolate ellipsoids oriented normally to surface of the film.

A nanocomposite film with layer-by-layer self-assembled gold nanospheres driven by cucurbit[7]uril for the selective transport of l-tryptophan and lysozyme

Selective separation of amino acids and proteins is crucial in various areas of research,including proteomics,protein structure and function studies,protein purification and drug development,and biosensing and biodetection.A nanocomposite film is formed by combining layer-by-layer self-assembled gold nanospheres(Au NPs)driven by cucurbit[7]uril(CB[7])and polymethyl methacrylate(PMMA)film.Due to the host-guest interactions,the selective transmission of l-tryptophan in the nanocomposite film is confirmed by the current-voltage measurements using a picoammeter.Furthermore,by adjusting the particle size of Au NPs to increase channel size,lysozyme containing multiple tryptophan residues can selectively pass through the nanocomposite film,indicating the high versatility and adaptability of the nanocomposite film.This study will provide a new direction for the selective separation of amino acids and proteins.

磁控溅射玫瑰金膜层的颜色及抗变色性能

[目的]玫瑰金因其优雅浪漫的颜色而被广泛用于装饰镀膜,但现有玫瑰金镀膜基本采用电镀工艺制备,存在严重的环境污染问题,需要寻求绿色环保的镀膜新工艺。[方法]采用磁控溅射镀膜工艺在316L不锈钢表面沉积Au85玫瑰金膜层。研究了溅射时间、靶电流和基体表面状态对膜层颜色的影响。检测了较佳工艺下所得膜层的抗变色性能。[结果]溅射时间在30 min以内变化时膜层颜色基本不受影响。靶电流从0.5 A增大至1.0 A时,膜层晶粒变粗,亮度下降,色度增大。基体表面状态会影响膜层颜色及不同方向的色差。在靶电流1.0 A下对镜面抛光的316L不锈钢磁控溅射15 min可获得较明亮的红色膜层,该膜层在模拟太阳光照射和人工模拟汗液浸泡试验中都表现出较好的抗变色性能。[结论]磁控溅射Au85玫瑰金镀膜工艺满足绿色环保和工艺饰品表面装饰要求,应用前景良好。

金薄膜辅助玻璃与砷化镓阳极键合

采用磁控溅射技术在砷化镓(GaAs)表面沉积一层厚度为1μm的金薄膜,将其作为中间层成功实现了Borofloat(BF33)玻璃与GaAs的连接。阳极键合实验结果表明键合电流在短时间内达到峰值,之后迅速降低并且稳定在一个很小的数值范围内,且键合电流峰值随着键合温度与键合电压的升高而增大。通过扫描电子显微镜(SEM)和能谱仪(EDS)对玻璃-GaAs键合界面进行微观形貌观察。结果表明键合界面良好,在400℃、700 V的条件下,玻璃-GaAs键合强度可达到1.53 J/m^(2),且键合强度随着键合温度与键合电压的升高而增大。

Au-NPs对氧化铌忆阻器界面修饰的影响

在阻变器件中,通过在氧化铌薄膜和底电极之间旋涂一层金纳米颗粒(Au-NPs)作为界面修饰层,可以明显降低氧化铌忆阻器的阈值电压,提高阈值电压分布的集中性。通过扫描电子显微镜发现,旋涂在底电极上面的Au-NPs分布较为均匀,有利于器件在Au-NPs等固定位置形成导电细丝,从而降低了导电细丝随机形成的可能性。I-V循环测试证实了Au-NPs的引入明显增强了空间电荷限制电流的输运特性,表明有利于固定导电细丝的生长,提升器件稳定性。