Optical performance of ultra-thin silver films under the attenuated total reflection mode

Ultra-thin silver films were deposited by thermal evaporation, and the dielectric functions of samples were simulated using Drude-Lorentz oscillators. When s-polarized incident light from the BK7 glass into thin silver film at 45°angle using attenuated total reflection （ATR） mode, we experimental observed that the reflection reach a minimum of 1.87% at 520 nm for thickness of d--6.3 nm silver film, and it reach a minimum of 10.1% at 500 nm for thickness of d--4.1 nm. Moreover, we simulated the absorption changes with incident angles at 520 nm for both p-polarized （TM wave） and s-polarized （TE wave） light using transfer matrix theory, and calculated the electric field distributions. The absorption as a function of incident angles of TM wave and TE wave showed different characteristics under ATR mode, TE wave reached the maximum absorption around the critical angle θc-41.1°, while TM wave reached the minimum absorption.

Surface Enhanced Raman Scattering on Self-assembled Nano Silver Film Prepared by Electrolysis Method

We demonstrate surface enhanced Raman scattering （SERS） detection of self-assembled nano silver film using a low-cost electrolysis strategy at a proper voltage and silver nitrate concentration in electrolyte. The concentration dependence of SERS from crystal violet （CV） molecules adsorbed to silver film was systematically studied. Importantly, the SERS surface enhancement factor of such nano silver film was 603, which was measured by a portable Raman spectrometer. The minimum concentration of detectable CV molecules can be as low as 10^-11 mol/L. The nano silver film prepared by this electrolysis method is an active, stable, cost-effective, and reusable SERS substrate.

Preparation of Nano Silver/Silk Fibroin Composite Films

In this study, the outstanding biocompatibility of silk fibroin （SF） and the highly efficient anti-bacterial effect of nano silver （NS） were utilized to prepare SF/NS composite film with anti- bacterial property. The structure and property of the film were characterized. The results showed that the structure of SF in the film was mainly silk I. SF in the film was almost insoluble in water. The tensile strength of film with NS was significantly lower than that of films without NS. When the addition of NS was within the range of 0%-0.6%, the elongation at break had no significant difference. The antibacterial rate of the film on staphylococcus aurens and escherichia coil increased with the amount of NS. The minimum amount of NS in the fdm was O. 1% and the maximum amount was 0.5%.

Deposition of hexagonal boron nitride thin films on silver nanoparticle substrates and surface enhanced infrared absorption

Silver nanoparticle thin films with different average particle diameters are grown on silicon substrates. Boron nitride thin films are then deposited on the silver nanoparticle interlayers by radio frequency （RF） magnetron sputtering. The boron nitride thin films are characterized by Fourier transform infrared spectra. The average particle diameters of silver nanoparticle thin films are 126.6, 78.4, and 178.8 nm. The results show that the sizes of the silver nanoparticles have effects on the intensities of infrared spectra of boron nitride thin films. An enhanced infrared absorption is detected for boron nitride thin film grown on silver nanoparticle thin film. This result is helpful to study the growth mechanism of boron nitride thin film.

A new approach for deposition of silver film from AgCl through successive ionic layer adsorption and reaction technique

An attempt was made to deposit thin film of silver onto the glass substrate by using Ag Cl precursor, instead of conventional precursor AgNO_3 with vitamin C by inexpensive and convenient successive ionic layer adsorption and reaction(SILAR) method. The deposited silver thin film was characterized by X-ray diffraction(XRD) analysis, scanning electron microscope(SEM), UV-visible and electrical I-V study. The diffraction study showed FCC structure of metallic silver in good agreement with the standard values of JCPDS(04–0783). SEM reveals flower like nano particles produced on the substrate. The surface plasmon resonance(SPR) peak in the UV-visible spectrum shows maximum absorption at 350 nm. The film shows an ohmic behavior and its electrical resistivity was found ~103 ?·cm at room temperature.

The Effect of Laser Irradiation on Surface Enhanced Raman Scattering for Silver Film

The laser irradiation effect on the SERS intensity for Ag film is discussed using crystal violet (CV) as a probe. The thickness of silver film,the etching time of the glass slide by gaseous hydrogen fluoride, and the laser irradiation time for different amounts of CV on silver films were investigated. The laser burn out model was proposed to explain the dependence of the SERS intensity of CV on the laser irradiation time.

Angle-sensitive and fast photovoltage of silver nanocluster embeded ZnO thin films induced by 1.064-μm pulsed laser

Silver nanocluster embedded ZnO composite thin film was observed to have an angle-sensitive and fast photovoltaic effect in the angle range from -90° to 90° , its peak value and the polarity varied regularly with the angle of incidence of the 1.064-μm pulsed Nd：YAG laser radiation onto the ZnO surface. Meanwhile, for each photovoltaic signal, its rising time reached -2 ns with an open-circuit photovoltage of -2 ns full width at half-maximum. This angle-sensitive fast photovoltaic effect is expected to put this composite film a candidate for angle-sensitive and fast photodetector.

Fabrication Silver Film inside Silica Capillary

To study hollow waveguides for CO 2 laser transmission,a liquid-phase depositi on technique is applied to form a silver film inside silica capillary based on t he method of silver mirror reaction.Using this fabrication method,the optimum co mbination of different parameters is gained and hollow waveguides have been made successfully with a bore size of 1mm and a guide with length of as long as 2m o n self-producing apparatus.To meet quality silver film,a relative high temperat ure,low flowing speed and long time are adopted on the basis of low reactant con centration.The maximum transmission efficiency of hollow-core fiber without die lectric coating can be up to 85 percent and loss can be low to 0.5dB/m,maximum o utput power is 53W for stable 20mintues.

Fabrication of Large-area 3-D Ordered Silvercoated Colloidal Crystals and Macroporous Silver Films Using Polystyrene Templates

The highly ordered silver-coated colloidal crystals arrays and macroporous silver films were derived through an electrostatics-induced adsorption effect using polystyrene(PS) as templates. Carboxyl-modified PS microspheres were prepared by emulsifier-free emulsion polymerization using methacrylic acid(MAA) as the functional monomer. PS microspheres were self-assembled into close packing colloidal crystals of facecentered cubic arrays to the substrate with vertical deposition method. These colloidal crystals were modified using dopamine(DA) to form poly-dopamine(PDA) during its oxidative polymerization. Through electrostatic interaction, the silver nanoparticles were deposited and adsorbed onto the surfaces of colloidal crystals templates by exposing [Ag(NH_3)_2]^+solution to infrared irradiation. Removal of the polymeric template by etching with methylbenzene solvent resulted in 3D ordered macroporous silver films. The structural and properties of the ordered silver-coated arrays and macroporous silver films were characterized by field emission scanning electron microscopy(FE-SEM), X-ray diffraction(XRD), UV-vis spectroscopy and surface-enhanced Raman spectroscopy(SERS). The results indicate that the prepared silver-coated arrays and macroporous silver films possess the features of ordered multilayer arrangement, uniformity and repeatability as well as an ideal SERS effect.

Evolution of the structural and optical properties of silver oxide films with different stoichiometries deposited by direct-current magnetron reactive sputtering

Nitrogen doping of silver oxide （AgxO） film is necessary for its application in transparent conductive film and diodes because intrinsic AgxO film is a p-type semiconductor with poor conductivity. In this work, a series of AgxO films is deposited on glass substrates by direct-current magnetron reactive sputtering at different flow ratios （FRs） of nitrogen to 02. Evolutions of the structure, the refiectivity, and the transmissivity of the film are studied by X-ray diffractometry and sphectrophotometry, respectively. The specular transmissivity and the specular refiectivity of the film decreasing with FR increasing can be attributed to the evolution of the phase structure of the film. The nitrogen does not play the role of an acceptor dopant in the film deposition.

COVALENTLY ATTACHED MULTILAYER ULTRA-THIN FILMS FROM DIAZORESIN AND CALIXARENES

A kind of photosensitive ultra-thin film was fabricated from diazoresin (DR) and various calixarenes by using theself-assembly technique. Under UV irradiation both the ionic- and hydrogen bonds between the layers of the film will convert into covalent bonds. As a result, the stability of the film toward polar solvents increases dramatically.

CHEMICALLY DEPOSITED SILVER FILM USED AS A SERS-ACTIVE OVER-COATING LAYER FOR POLYMER FILM

When colloidal silver particles were chemically deposited onto polymer film as an over-coating layer, surface-enhanced Raman scattering (SERS) spectra could be collected for the surface analysis. SERS measurements of liquid crystal film were successfully performed without disturbing the surface morphology.

Improvement of the Conductivity of Silver Nanowire Film by Adding Silver Nano-Particles

The change of conductivity and transparency of silver nanowire （AgNW） films by adding silver nano-particles （AgNPs） onto their surface is studied. The results show that the conductivity of the AgNW film is greatly improved with its sheet resistance reduced about 78. 7% to 51.9Ω/sq, and there is no obvious reduction of the transmittance. Further studies show that there is a self-assembling process pushing the AgNPs to concentrate at the intersecting points between AgNWs to weld them, which would reduce the intersection resistance between the AgNWs. This self-assembling behavior is led by the surface interactivities among the dispersing liquid of AgNPs, the surface of the substrate and AgNWs when the dispersing liquid is drying.

Performance improvement in polymeric thin film transistors using chemically modified both silver bottom contacts and dielectric surfaces

An efficient interface modification is introduced to improve the performance of polymeric thin film transistors. This efficient interface modification is first achieved by 4-fluorothiophenol（4-FTP） self-assembled monolayers（SAM） to chemically treat the silver source–drain（S/D） contacts while the silicon oxide（SiO2） dielectric interface is further primed by either hexamethyldisilazane（HMDS） or octyltrichlorosilane（OTS-C8）. Results show that contact resistance is the dominant factor that limits the field effect mobility of the PTDPPTFT4 transistors. With proper surface modification applied to both the dielectric surface and the bottom contacts, the field effect mobilities of the bottom-gate bottom-contact PTDPPTFT4 transistors were significantly improved from 0.15 cm^2·V^-1·s^-1 to 0.91 cm^2·V^-1·s^-1.

Linear instability of ultra-thin liquid films flowing down cylindrical fibre

The stability characteristics of an ultra-thin layer of a viscous liquid flowing down a cylindrical fibre are investigated by a linear theory. The film with the thickness less than 100 nm is driven by an external force and under the influence of the van der Waals forces. The results show that, when the relative film thickness decreases, the curvature of the fibre depresses the development of the linear perturbations, whereas the van der Waals forces promote the instabilities. This competition results in a non-monotonous dependence of the growth rate on the relative film thickness. The critical curves are also obtained to describe the transition from the absolute instability to the convective instability, indicating that the van der Waals forces can enlarge the absolutely unstable region. Furthermore, the surface tension can cause the development of the absolute instability, whereas the external force has an opposite effect.

Molecular Dynamics of Ultra-thin Lubricating Films under Confined Shear

The molecular dynamics simulation of ultra-thin films under confined shear was performed to investigate the relation between dynamic properties of ultra-thin films and their microstructure. The solid walls were modelled using an Au crystal and the fluid molecules were modeled using decane. The simulation results indicate that the microstructure of ultra-thin films is a kind of solid-like layering structure. The density and velocity profiles of the fluid molecules are symmetric. The slip and shear thinning behavior was founded and interpreted.A mathematic model was set up according to the results of the simulation and experiments.

Molecular dynamics of dewetting of ultra-thin water films on solid substrate

Molecular dynamics simulation is applied to study the instability and rupture process of ultra-thin water films on a solid substrate. Results show the small disturbance of the film will develop linearly due to the spinodal instability, whereas the interaction between solid and liquid has less influences on the initial growth. Then the rupture occurs and the rim recedes with a dynamic contact angle. The radius of the rim. varies with time as the square root of t, which is consistent with the macroscopic theory available. Stronger interaction between solid and liquid will postpone rupture time decline the dynamic contact angle and raise the density of water near the interface between solid and liquid.

Study on electrostatic discharge(ESD)characteristics of ultra-thin dielectric film

Electrostatic discharge(ESD)event usually destroys the electrical properties of dielectric films,resulting in product failure.In this work,the breakdown characteristic of machine mode(MM)ESD on three different nano size films of head gimble assemble are obtained experimentally.The breakdown voltage and thickness parameters show a positive proportional relationship,but they are generally very low and have large discrete characteristics(~30%).The maximum and minimum breakdown voltages of the tested samples are 1.08 V and 0.46 V,which are far lower than the requirement of the current standard(25 V).In addition,the judgment criterion of product damage is given,and the relationship between discharge voltage polarity,initial resistance and breakdown voltage is studied.Finally,the theoretical analysis of the breakdown characteristic law has been given.

Temperature Dependent Surface Resistivity Measures of Commercial, Multiwall Carbon Nanotubes (MWCNT), and Silver Nano-Particle Doped Polyvinyl Alcohol (PVA) Films

Pure and doped Polyvinylidene difluoride (PVDF) films, for the detection of infrared radiation, have been well documented using the mechanism of pyroelectricity. Alternatively, the electrical properties of films made from Polyvinyl Alcohol (PVA) have received considerable attention in recent years. The investigation of surface resistivities of both such films, to this point, has received far less consideration in comparison to pyroelectric effects. In this research, we report temperature dependent surface resistivity measurements of commercial, and of multiwall carbon nanotubes (MWCNT), or Ag-nanoparticle doped PVA films. Without any variation in the temperature range from 22°C to 40°C with controlled humidity, we found that the surface resistivity decreases initially, reaches a minimum, but rises steadily as the temperature continues to increase. This research was conducted with the combined instrumentation of the Keithley Model 6517 Electrometer and Keithley Model 8009 resistivity test fixture using both commercial and in-house produced organic thin films. With the objective to quantify the suitability of PVDF and PVA films as IR detector materials, when using the surface resistivity phenomenon, instead of or in addition to the pyroelectricity, surface resistivity measurements are reported when considering bolometry. We found that the surface resistivity measurements on PVA films were readily implemented.

A STUDY ON VOLTAMMETRIC BEHAVIOR OF INDIGO CARMINE AND ITS MIXTURE WITH AMARANTH AT MERCURY FILM ELECTRODE ON SILVER SUBSTRATE

The voltammetric behavior of indigo carmine at mercury film electrode on a silver substrate (MFES) was studied in this paper. It was found that indigo carmine gave a sensitive reduction peak at a potential (Vp) of -0.11 V at pH 4.0 in aqueous solution. The MFES gave good reproducibility and life time. The peak currents (ip) depended lipearly on the concentrations of indigo carmine free 0 to 100 ng/ml. The Vp and Ip of indigo carmine at MFES were independent of the concentrations of amaranth at pH 4.0, the Vp of amaranth was -0.24 V at this pH. The differences of Vp between both colorants enabled to distinguish indigo carmine free amaranth.