A Study of Surfactant-Induced Growth of Ag on Ag （111）

A new growth model is introduced to describe surfactant-induced growth of Ag on Ag （111） with realistic physical parameters. In this model, the A-S exchange mechanism is considered for the first time. Using the Monte Carlo simulations, the influence of exchange mechanism, surface temperature T, the exchange barrier Eεx, and the coverage of surfactant θM on the growth mode and morphology during multilayer film growth of Ag/Ag （111） are studied in detail Both the referenced value of surfactant coverage and the method to obtain perfect layer-by-layer film in surfactantinduced Ag/Ag （111） system are provided. Our simulation results are consistent with many experimental observations for surfactant-induced growth of Ag on Ag （111）.     

Effects of Ag on Electrical Properties of Ag/Ni/p-GaN Ohmic Contact

Properties of the Ag/Ni/p-GaN structure at different temperatures are studied by Auger electron spectroscopy, scanning electron microscopy and high resolution x-ray diffraction. The effect of Ag in ohmic contact on the crystalline quality is investigated and the optimized value of annealing temperature is reported. The lowest specific contact resistance of 2.5 × 10^-4 Ωcm^2 is obtained at annealing temperature of 550^o C.     

Simulation of surfactant effect on growth of metal homoexpitaxial Sb－Ag/Ag(111)

A kinetic Monte Carlo simulation is performed in order to study the effect of Sb atoms as a surfactant on the growth of Ag on Ag(111). In our model the repulsive mechanism in which the surfactant Sb atoms repel diffusing Ag adatoms, and the exchange mechanism between Ag and Sb atoms, are considered. Our simulations show that the effects of Sb atoms for Ag/Ag(111) growth system are mainly to increase the chances for Ag atoms to overcome the Ehrlich--Schwoebel barrier both in the interlayer growth and along the edge diffusion. The influence of the coverage of Sb atoms and substrate temperature on the growth of Ag/Sb/Ag(111) is discussed.     

Investigation of excitation of Ag atoms in internal conversion of γ rays

Excitation of Ag atoms in the internal conversion of γ rays due to the E3 transition in ^109m Ag has been measured on an anti-Compton spectrometer and a multidimensional-coincidence spectrometer with GeSi(Li) detectors. The probability of double ionization of the K shell is determined to be P _KK =(2.5 ± 0.2) × 10^?4. It is shown that the direct process is dominant in excitation of Ag atoms.     

Two-photon transitions of Ag− centers in KBr

Abstract

Two-photon excitation spectra of Ag^? centers in KBr have been measured. The main excitation peak appears only with linearly polarized excitation and has been assigned to the ¹A_1g → ¹A_1g transition. Weaker structures have a polarization dependence corresponding to ¹A_1g → ¹E _g and ¹A_1g → ¹T_2g transitions.     

STM investigation of the reaction of AgO added rows with CO2 on a Ag(110) surface

The formation of carbonate species by a reaction of AgO added rows with CO₂ was investigated by scanning tunneling microscopy (STM). STM observation during the reaction revealed that the AgO added rows were compressed from a (4 × 1) to a (2 × 1) phase, according to the growth of carbonate domains. Though the carbonate domains give a (1 × 2) diffraction pattern, STM images of this domain do not show a (1 × 2) structure, which indicates that the Ag substrate reconstructs to a (1 × 2) structure. Though the CO₃ species thermally decompose at a lower temperature than AgO added rows, the AgO added rows can be selectively decomposed by ultraviolet irradiation.     

Synthesis of Ag metallic nanoparticles by 120 keV Ag− ion implantation in TiO2 matrix

TiO₂ thin film synthesized by the RF sputtering method has been implanted by 120 keV Ag^? ion with different doses (3?×?10¹⁴, 1?×?10¹⁵, 3?×?10¹⁵, 1?×?10¹⁶ and 3?×?10¹⁶ ions/cm²). Further, these were characterized by Rutherford back Scattering, XRD, X-ray photoelectron spectroscopy (XPS), UV–visible and fluorescence spectroscopy. Here we reported that after implantation, localized surface Plasmon resonance has been observed for the fluence 3?×?10¹⁶ ions/cm², which was due to the formation of silver nanoparticles. Ag is in metallic form in the matrix of TiO₂, which is very interestingly as oxidation of Ag was reported after implantation. Also, we have observed the interaction between nanoparticles of Ag and TiO₂, which results in an increasing intensity in lower charge states (Ti³⁺) of Ti. This interaction is supported by XPS and fluorescence spectroscopy, which can help improve photo catalysis and antibacterial properties.     

Chemical composition and magnetism of Ag doped LaMnO3

By using a sol-gel clue, a set of polycrystalline perovskite samples La1-xAgxMnO3 with a nominal doping level x ranging from 0.05 to 0.45 has been synthesized. The chemical composition and the magnetism of the samples were investigated. A little Ag was： found seeping from the samples in the sintering process when the doping level exceeded 0.05 and the sintering temperature was higher than 700℃ resulting in the samples being in multiphase. The magnetic transition points of the samples have been found to decrease with increasing sintering temperature. A concentration-dependent Tc similar to that of bivalent metal ion doped perovskite, has been obtained. We believe that the Ag seeping in the sintering process is responsible for those magnetic characteristics.     

Directional solidification of Al–Cu–Ag alloy

Al–Cu–Ag alloy was prepared in a graphite crucible under a vacuum atmosphere. The samples were directionally solidified upwards under an argon atmosphere with different temperature gradients (G=3.99–8.79 K/mm), at a constant growth rate (V=8.30 μm/s), and with different growth rates (V=1.83–498.25 μm/s), at a constant gradient (G=8.79 K/mm) by using the Bridgman type directional solidification apparatus. The microstructure of Al-12.80-at.%–Cu-18.10-at.%–Ag alloy seems to be two fibrous and one lamellar structure. The interlamellar spacings (λ) were measured from transverse sections of the samples. The dependence of interlamellar spacings (λ) on the temperature gradient (G) and the growth rate (V) were determined by using linear regression analysis. According to these results it has been found that the value of λ decreases with the increase of values of G and V. The values of λ ² V were also determined by using the measured values of λ and V. The experimental results were compared with two-phase growth from binary and ternary eutectic liquid.     

Electrical Explosion of Wires for Manufacturing Bimetallic Antibacterial Ti–Ag and Fe–Ag Nanoparticles

Russian Physics Journal - Using a simultaneous electrical explosion of two twisted wires, bimetallic Ti–Ag and Fe–Ag nanoparticles are synthesized, where the component ratios are...     

Experimental and theoretical investigations of the Knight shift of Pd and Ag in the alloy system Ag x Pd1−x

The Knight shift of Pd in Ag _x Pd_1–x has been determined for concentrationsx0.2. In full accordance with the expectations based on the behaviour of the magnetic susceptibility, it was found that the Knight shift of Pd is rapidly reduced in magnitude by adding Ag to Pd. To allow for a detailed interpretation of this finding, we have performed Korringa-Kohn-Rostoker coherent potential approximation (KKR-CPA) band structure calculations for Ag _x Pd_1–x . These calculations clearly demonstrate that the decrease in spin susceptibility with increasingx is accompanied with a decrease in core polarization. In contrast to Pd, the negative Knight shift of Ag on the Pd-rich side of the system is caused by the valence band contribution, as it is demonstrated by our calculations. This is caused by an intersite effect in analogy to the transferred hyperfine field found for non-magnetic elements dissolved in a magnetic host.     

Polarization dependence of the light coupling to surface plasmons in an Ag nanoparticle & Ag nanowire system

Polarization dependence of the coupling of excitation light to surface plasmon polaritons(SPPs) was investigated in a Ag nanoparticle–nanowire waveguide system(a Ag nanoparticle attached to a Ag nanowire). It was found that under the illumination of excitation light on the nanoparticle–nanowire junction, the coupling efficiency of light to SPPs depends on the polarization of the excitation light. Theoretical simulations revealed that it is the local near-field coupling between the nanoparticle and the nanowire that enhances the incident light to excite the nanowire SPPs. Because the shapes of the Ag nanoparticles differ, the local field intensity, and thus the excitement of the nanowire SPPs, vary with the polarization of the excitation light.     

Effect of Ag Doping on Optical and Electrical Properties of ZnO Thin Films

ZnO thin films were prepared on p-type Si (100) substrates by the sol-gel process. The influence of Ag doping at a content of 0.002% on the photoluminescence and current-voltage (I - V) characteristics of ZnO thin films has been investigated. It is found that Ag doping leads to a pronounced increase in the intensity of near band edge emission at 3.23eV and a remarkable red shift of the visible broadband at room temperature. The I - V characteristics of ZnO/p-Si heterojunctions are also changed. These results could be explained by Ag substituting for Zn in Ag doped ZnO thin films.     

Evolutionary Plasmonic Properties of Single Truncated Ag Nanowire-on-Au Film Nanocavity

Noble metal nanocavities have been widely demonstrated to possess great potential applications in nanooptics and nanophotonics due to their extraordinary localized surface plasmon resonance. However, most metal nanocrystals synthesized by chemical methods often suffer from truncation with different degrees due to oxidation and dissolution of metal atoms at corner and edges. We investigate the influence of shape truncation on the plasmonic properties of single Ag nanowire on Au film nanocavity us...     

Growth Mechanism of Vertically Aligned Ag（TCNQ） Nanowires

Highly oriented Ag(TCNQ) nanowires have been prepared on Si(111) wafer at 1O0℃ by the vapour-transport reaction between silver and TCNQ without any other catalyst. X-ray diffraction analysis shows that the composition and crystal structure of the obtained nanostructure were Ag(TCNQ) crystalline. Most Ag(TCNQ) nanowires were grown uniformly and vertically on the substrate with diameters ranging from 50 to 30Onto and the lengths measuring from 2 to 50μm by scanning electron microscopy. Ag particles were observed on the substrate from pure thin Ag film heated under the same conditions as used in synthesizing the nanowires. Nucleation and short Ag(TCNQ) nanowires were prepared by controlling the reaction time, providing direct evidence of the growth mechanism in a nanometre scale. The growth process was explained according to the vapour-liquid-solid model. The gradient of temperature and the densely distributed Ag particles may contribute to the vertically aligned growth. These results will be helpful for the controllable synthesis of Ag(TCNQ) nanowires.     

Preparation and magnetic properties of Fe–Ag granular alloy

An aqueous solution of AgNO₃ in the presence of ammonia and Fe(CO)₅ is sonicated under a H₂/Ar mixture, yielding a nanostructured homogeneous phase of Ag/Fe₂O₃. This composite material is further reduced at 300°C under hydrogen to produce the nanophased Fe/Ag solid mixture. The as-prepared material, as well as the reduced mixture, is analyzed by various conventional methods. Magnetization loops, ESR, Mössbauer, and magnetoresistance measurements are also conducted to determine the magnetic properties of the products.     

In-beamγ-ray spectroscopy of the neutron deficient100Ag

The neutron deficient nucleus¹⁰⁰Ag, three proton holes below and three neutron particles above the N=Z=50 shell closure at¹⁰⁰Sn, has been identified and studied by in-beam spectroscopy. The reactions⁴⁶Ti(⁵⁸Ni,3pn) at 231 MeV and⁶⁴Zn(⁴⁰Ca,3pn) at 167 MeV of the respective⁵⁸Ni and⁴⁰Ca beams were used, and states up to 8.7 MeV excitation energy and spin I?20 were found in two mainγ-ray cascades forming band-like structures of even and odd parity. Large scale shell model calculations suggest predominantπg ₉ ^2/?3 ν(d_5/2,g_7/2)³ andπg ₉ ^2/?3 ν(d_5/2,g_7/2)²h_11/2 structures with maximum spins I ^π = 19⁺ and I ^π =22^?, respectively, for the two level sequences. The influence ofπp_1/2 vs.νh_11/2 excitations is discussed for low lying odd-parity levels.     

Multiple Scattering Effects of Ag Particles in Random Ag-SiN Film

A layer of 40nm-thick Ag-SiN film with Ag nano-particles embedded and distributed randomly in the SiN thin film were deposited by the method of radiant-frequency magnetron sputtering. Specimens orderly comprising a random Ag-SiN film and an optical phase change recording layer were exposed to a focused laser beam with wavelength of 69Ohm. It is shown that, with a random Ag-SiN layer deposited above the recording layer. Calculation by the finite difference time domain method of a 4Ohm-thick SiN film under a Gaussian beam irradiation has been carried out to simulate the near-field distribution in the film, which showed a huge local near-field intensity enhancement of about 200 times if small Ag particles with diameter of 6 nm were modelled inthe SiN film in the central region of the in cident laser spot.     

Electrical resistivity and superconductivity of amorphous La−Ag alloys

We report on measurements of the electrical resistivity and the superconducting transition temperature of amorphous La–Ag alloys (60–74 at % La) obtained by liquid quenching. The temperature coefficient of the resistivity is always slightly negativ, its value cannot be described well by existing theories.T _c depends linearly on the La content and seems to be not very sensitive to the second alloy constituent.Dedicated to Prof. Dr. W. Buckel on the occasion of his 60th birthday