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Results obtained from the optical absorption and photoluminescence (PL) spectroscopy experiments have shown the formation of excitons in the silver-exchanged glass samples.These findings are reported here for the first time. Further, we investigate the dramatic changes in the photoemission properties of the silver-exchanged glass samples as a function of postannealing temperature. Observed changes are thought to be due to the structural rearrangements of silver and oxygen bonding during the heat treatments of the glass matrix.In fact, photoelectron spectroscopy does reveal these chemical transformations of silverexchanged soda glass samples caused by the thermal effects of annealing in a high vacuumatmosphere. An important correlation between temperature-induced changes of the PL intensity and thermal growth of the silver nanoparticles has been established in this Letter through precise spectroscopic studies.

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The formation and growth of nanoscale silver clusters in silica matrices are studied by means of optical absorption and Raman scattering spectroscopy. The metallic silver layer of the Ag/SiO2 couple was irradiated by argon ions for ion-beam mixing of silver with the silica matrix. Postannealing of the embedded Ag atoms in silica matrices results in the growth of Ag nanoclusters. The quadrupolar surface acoustic vibrational mode of the Ag nanoclusters has been observed in low-frequency Raman scattering experiments. The average size of these Ag nanoclusters is estimated from the quadrupolar mode frequency. Systematic growth of Ag nanoclusters embedded in silica matrices is observed with the increase of postannealing temperature. We have estimated the activation energy for the diffusion of Ag atoms in irradiated a-SiO2 from the coarsening of these embedded Ag atoms. Development of a peak at about 3 eV in the optical absorption spectra for the samples postannealed at higher temperatures corroborates further the growth of Ag nanoclusters in the silica matrices. New Raman modes at 1368 and 1573 cm−1 are observed in Ag embedded silica samples and the possible origin of these modes is discussed.

Temperature-controlled-growth of silver nanoclusters in soda glass matrix is investigated by low-frequency Raman scattering spectroscopy. Growth of the nanoclusters is ascribed to the diffusion-controlled precipitation of silver atoms due to annealing the silver-exchanged soda glass samples. For the first time, Rutherford backscattering measurements performed in this system to find out activation energy for the diffusion of silver ions in the glass matrix. Activation energy for the diffusion of silver ions in the glass matrix estimated from different experimental results is found to be consistent.Comment: 16 pages, 5 figures, pdf fil