Schematic representation of the possible morphologies for nanosystems: (1) outside cluster, (2) islandlike, and (3) continuous film.
(a) Laser reflection interferometry traces recorded during deposition on for specimens belonging to set 1 (see Table I). (b) LRI traces recorded during the growth of selected specimens deposited at a rf and different total pressures. On lowering the total pressure, the deposited gold amount (and the final reflectance value) progressively increases, indicating thus a transformation from islandlike nanosystems to continuous gold films on silica. In both figures, the vertical line marks the end of the deposition experiment ( min).
Calibration curve for film thickness as a function of the final reflectance recorded at the end of deposition experiments.
GIXRD patterns for nanosystems belonging to set 1 in the range . The vertical lines indicate the peak positions reported for bulk gold [Pattern no. 4-784, JCPDS, (2000)].
Dependence of nanocrystal size on rf power for nanosystems synthesized at different total pressures.
Dependence of surface percentage on the applied rf power for sample sets 1, 2, 3, and 4 (see Table I). The horizontal line marks the limit of the percolation threshold. Atomic percentages have been calculated including , , and photoelectron peaks.
(a) Optical absorption spectra of nanosystems belonging to set 1 . (b) Representative spectra of typical clusterlike and islandlike specimens synthesized under different conditions.
Selected AFM images for nanocomposites belonging to set 1 at different RF powers: (a) and (b) .
(a) Bright-field (BF) TEM image of a specimen obtained in the same conditions as sample 15 (, rf ) on the amorphous carbon of TEM grid for a sputtering time=30 min. (b) High-resolution (HR) micrograph of the same sample. (c) BF TEM image of a specimen deposited on the amorphous carbon of TEM grid in the same conditions as sample 1 (, rf , min). (d) HR micrograph of the same specimen.
Diagram representing nanocomposite morphology (clusterlike/islandlike/continuous) as a function of the applied rf power and total pressure. The markers denote yellow gold films () , green ones () (#), blue islandlike , and pink clusterlike nanosystems, respectively. For each point, the average crystallite size determined by GIXRD analyses is reported. The dashed line marks the borderline between discontinuous and continuous systems.
Synthesis conditions for nanosystems. The thickness values for continuous gold films on silica are also reported. and denote the substrate temperature and deposition time respectively.
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