Modifications in silver-doped silicate glasses induced by ns laser beams (original) (raw)
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Laser beam irradiation of silver doped silicate glasses
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2010
Planar light waveguides prepared by Ag-Na ion exchange in molten salt bath are irradiated with Nd:YAG laser beams at different wavelengths in the IR and VIS regions, and for different energy density and repetition rate values. The samples are characterized by optical spectroscopy to determine the role of irradiation parameters in the Ag clustering process, including aggregation phenomena and possible cluster photofragmentation. The appearance of the characteristic plasmon resonance feature in the optical absorption spectra marks the formation of Ag clusters, as observed by electronic microscopy as well, and permits to follow the evolution of the whole clustering process upon increasing of the deposited energy density. Photoluminescence spectroscopy has given specific information concerning the presence of Ag multimeric aggregates, considered as embryonic structures for the growing nanoclusters. The systematic investigation presented in this work is expected to clarify some aspects of the interaction between the laser beam and the doped glass matrix, and to help establishing suitable methodologies for the controlled preparation of nanocomposite glasses.
Journal of Physics: Conference Series, 2016
Plasmonic Ag nanostructures were generated in glass surfaces by means of UV laser irradiation (193 nm). The aim of the work was to identify the correlations between the atomic structure of such nanoparticles and their optical properties. The structural characterization of the samples, prepared with different number of laser pulses was performed by Ag K-edge EXAFS. The processing of the spectra by the Fourier-transform analysis gave the values of Ag-Ag and AgO interactions averaged over ionic and neutral states of silver in the sample. The consistent analysis of the behavior of features in optical spectra and the obtained dependencies of Ag-Ag and AgO structural parameters upon the number of laser pulses enabled to suggest the mechanism of plasmonic Ag nanoparticles formation in silicate glass, which is influenced by the interaction with polyvalent ions (for example Fe 2+) and by defect centers (for example HTC and NBOHC centers) generated by UV irradiation.
Applied Surface Science, 2012
Ion exchange process is widely used to dope silicate glass layers with silver for several applications, ranging from light waveguide to nanostructured composite glass fabrication. The silver-doped structure and its physical properties depend on the preparation parameters as well as on subsequent treatments. In particular, laser irradiation of the ion exchanged glasses has been demonstrated to be an effective tool to control cluster size and size distribution. Nevertheless, a complete comprehension of the basic phenomena and a systematic characterization of these systems are still lacking. In this paper, an extended optical characterization is presented for soda-lime glass slides, doped with silver by Ag + -Na + ion exchange, thermally treated and irradiated with a Nd:YAG laser beam at different wavelengths, and for different energy density. The samples were characterized by various spectroscopic techniques, namely, optical absorption, photoluminescence and micro-Raman analysis. The availability of all these characterization techniques allowed pointing out a suitable scenario for the Ag clustering evolution as a function of the ion exchange, annealing and laser irradiation parameters.
Formation of nanoclusters in silver-doped glasses in wet atmosphere
Journal of Physics: Conference Series, 2007
Thermal stability of silver ions in silicate glasses in dry and wet (0.5-50% of water content) atmosphere under elevated (160-230 o C) temperature is studied. The glass is doped with silver using silver-to-sodium ion exchange procedure conventionally used for the formation of optical waveguides. It is found that the isothermal annealing of glasses doped with Ag + ions in a wet argon atmosphere leads to the reduction of silver to metallic state and to the formation of silver nanoclusters in the glass body. The clustering in the course of water diffusion into the glass was studied by optical spectrometry. The clusters were not formed during annealing in a dry atmosphere at the same temperatures.
EXAFS study on Ag-doped silicate glasses irradiated with low-mass ions
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 1996
We present an EXAFS study on Ag-doped soda-lime glass waveguides obtained by ion-exchange and treated by low-mass ion-irradiation to promote the formation of metallic clusters. For differently prepared samples we have determined the Ag local order before and after the treatment. In the as-exchanged glasses Ag is coordinated with 0 at a distance significantly shorter than the Na-0 bond length in the unexchanged glass. In irradiated samples we found the formation of metal aggregates. Structural parameters of clusters in high-temperature irradiated sample are compatible with a compressed fee structure while in room-temperature irradiated specimen a more complicated structure comes out. 0.2 TiO, with trace amounts of Fe,O,, As,O,, Cs,O, in silver-containing molten salt baths. During the process, metal dopant ions diffuse from the bath into the glass, replacing sodium ions that outcome to dilute the molten salt. In this way layers few to several microns thick were obtained with metal surface concentmtion in the 10" at/cm3 range.
Plasmonics, 2012
Silver-exchanged silicate glass has been irradiated by 532-nm pulsed Nd:YAG laser in order to locally form metallic nanoparticles. The particular interest of this process is to locally control the silver nanoparticles (NPs) growth. Silver ions are exchanged with sodium ions near the glass surface after dumping of a silicate glass few minutes in silver and sodium nitrates molten salt. A low-energy density laser exposure (0.239 J/cm 2) chosen at the ablation threshold allows to observe the kinetics of the silver NPs growth according to the increasing shots number. An on-line optical measurement is carried out after each shot to identify the most important steps during the irradiation process. According to this measurement, we have determined four steps highlighted by UV/ Visible spectrophotometry and we have identified the influence of located surface plasmon resonance. Three combined material analysis methods were used to understand the glass/ laser interaction mechanism: we outlined the material volume variations by profilometric method, the element distribution by scanning electron microscopy and finally the structural distribution of the irradiated region by a local infrared investigation. The trend for NPs formation revealed by the UV/ Visible spectrophotometry is thus explained by the formation of a ring expelled from a central hole. We highlight that the online extinction measurement can be used to data process the NPs evolution.
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 2003
Extended X-ray absorption fine structure analysis is used to determine the silver local environment in silicate glasses doped by the Ag-alkali ion-exchange process, followed by different treatments, namely, ion irradiation, thermal annealing in reducing atmosphere, laser irradiation. The obtained results indicate that metal nanocluster composites with different cluster structures may be formed with these multistep methodologies, pointing out the role of the preparation parameters in giving rise to different features. Lattice parameters and cluster diameter were determined by grazing incidence X-ray diffraction.
Spectroscopic Investigation of Structural Rearrangements in Silver Ion-Exchanged Silicate Glasses
The Journal of Physical Chemistry C, 2012
The silver ion environment and the microstructural rearrangement of Ag + ÀNa + ion-exchanged glasses were investigated by means of micro-Raman and photoluminescence spectroscopies. The samples were produced by immersing borosilicate glasses in NaNO 3 : AgNO 3 molten salts baths with different molar ratios of silver nitrate. The modifications of the silica network microstructure were inspected by analysis of the Raman peak at about 1100 cm À1 , and the evolution with the silver concentration at the glass surface of the spectral components related to the different silica tetrahedral groups was studied. The formation of silver metal nanoparticles was inferred from the occurrence of the low-frequency Raman peak due to confinement of acoustic vibrations in metal clusters, and their dimensions were evaluated from the position of its maximum. In the light of the structural analyses performed by means of Raman spectroscopy, a final assignment of the different luminescence bands of silver embedded in silicate glasses was attained.
Photothermal-induced dichroism and micro-cluster formation in Ag+-doped glasses
Applied Physics B, 2004
In this paper, we report the observation of an induced dichroism in an ionic silver cluster-doped glass, under the interaction of a CW high-power (P max ∼ 8 W) Ar + laser beam. It is found that, as a result of the photo-thermal interaction, a dichroism due to the formation of chain-like silver clusters is induced. Because of the electromagnetic interaction, the orientation of these chain-like structures is related, in general, to the direction of the laser beam polarization. The effect is seen in the regime, where the laser beam power is increased rapidly. In this regime micrometer size (d ∼ 2 µm) clusters are generated on the surface of the sample. In this report, we discuss the production of such large silver clusters as a result of changing of the initial ionic clusters to the neutral ones and then aggregation of the generated small neutral clusters under the supersaturation condition.
Nanostructuring of silicate glass under low-energy Ag-ion implantation
Surface Science, 2004
Silicate glasses implanted by 30 keV Ag þ ions with a dose of 5 • 10 16 ion/cm 2 at ion current densities from 4 to 15 lA/ cm 2 were investigated using optical spectroscopy and atomic force microscopy (AFM). Optical spectroscopy measurements show a characteristic absorption band of surface plasmon resonance that is associated with nanosize Ag particles formed in the implanted glasses. Observed both the shift of transmittance band minimum to long wavelengths and the intensity change with rise of ion current density are caused by increase of the nanoparticle sizes. AFM images of the implanted glass surfaces show a formation of semispherical hills. These hills are tops of the spherical nanoparticles towering above the surface due to sputtering of the glass surface layer under the implantation. The increase of ion current density leads to enlarge of the hill size, i.e. nanoparticles. The nanoparticle enlargement is explained in terms of enhanced thermal diffusion of the implanted Ag atoms. Increase of the ion current density leads to temperature rise in the glass matrix that elevates atoms mobility and causes effective collection of the silver atoms into nucleated particles and their growth.