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The Maxwell-Garnett's and Toudert's methods detailed in Appl. Opt. 48, 778 (2009), based on the Maxwell-Garnett and Yamaguchi effective medium models, respectively, have been used for calculating the absorbance a of a (BaF2/Ag)5/BaF2 nanocomposite thin film identical to the one presented in Fig. i of Appl. Opt. 48, 778 (2009)]. We propose that the discrepancies observed in this reference between the (x spectra calculated by the two methods are due to a non rigorous use of both effective medium models by the author and show that adequate calculations lead to superposed spectra. OCIS codes: 310.6860, 240.6680, 160.4236.

Nanocermet trilayered thin films consisting of silver nanoclusters sandwiched between two dielectric layers are synthesized by ion-beam sputtering with an alternate deposition of the metal and the dielectric species. The evolution of the spectral position of the surface-plasmon resonance of the trilayers as a function of their structure are also investigated by optical transmittance measurements.

Ag-Cu mixed nanocrystals (NCs) are embedded in an amorphous Al(sub 2)O(sub 3) matrix by alternate ablation of pure metal and Al(sub 2)O(sub 3) targets. The composition of the NCs is varied from pure Cu to pure Ag.

Research describing a method of shape determination for nanocrystals in composite materials is presented. In particular the use of optical extinction spectroscopy with polarized light is shown to have applications in this field.

Vicinal sapphire surfaces with 1°, 5°, or 10° miscut angle from the (00l) planes have been annealed under different atmospheres in the temperature range from 1000 to 1500°C for a long time (from 30min to 64h). A systematic study by atomic force microscopy observations and grazing incidence small angle x-ray scattering measurements is undertaken in order to establish the influence of the miscut angle and the thermal conditions on the one dimensional (1D) ordering of the surface and on the resulting surface morphology. Several stages are identified in the evolution of the step period. First, after a very short time τ of thermal treatment, the surface reaches a periodic structure which corresponds to the self-ordering of single steps. Then, the step-bunching occurs, and the step period Λ increases following a power-law Λ=Λ0(t-τ/τ)n. Respect to the miscut angle, we identified several mechanisms of mass transport. Indeed, for surfaces with a miscut angle of 1°, the kinetics of step-bunching is controlled by diffusion of aluminum atoms, while, for miscut angles equal to 5° and 10°, the kinetics of step diffusion mechanism is governed by diffusion of oxygen atoms at the surface. [ABSTRACT FROM AUTHOR]

Morphological and crystallographic structures of multilayered W/Cu nanocomposite thin films elaborated by physical vapor deposition were studied by varying copper and tungsten thicknesses. Sample examinations were performed by x-ray diffraction (XRD), grazing incidence small-angle x-ray scattering and transmission electron microscopy (TEM). Samples were found to be composed of copper nanoparticles, homogeneously dispersed in planes parallel to the film-substrate interface and periodically separated by tungsten layers along the growth direction. Our observations revealed an original texture development of the tungsten matrix from a mixture of unexpected α-W<111> and α-W<110> components to unique α-W<110> component as the copper coverage passes a thickness threshold of 0.6 nm. Local TEM texture stereology investigations revealed simultaneous columnar growth of both preferential orientations posterior to polycrystalline development while XRD reveals strong compressive residual stresses in both texture components. Physical origins of the preferential crystallographic orientation evolution are discussed. Copper mono layers adsorption on W surfaces promotes surface energy anisotropy and diminution which is effective over the threshold. Below, the presence of a W(Cu) solid solution which does not affect substantially the texture is revealed by the stress-free lattice parameter value extracted from XRD. [ABSTRACT FROM AUTHOR]

The structure and optical response of Ag nanoparticles capped with dielectric BN, Al2O3, and Y2O3 layers have been studied. The morphological evolution of the nanoparticles has been investigated in detail by high-angle annular dark-field (HAADF) imaging in a scanning transmission electron microscope and by optical transmittance measurements and simulations of surface-plasmon resonances. We show that the quantitative analysis of plane-view HAADF images enables the average morphology of individual embedded nanoparticles to be revealed. It thus provides a simple method to investigate capping-layer effects, which are demonstrated to be characterized by a substantial reduction of the aspect ratio of the nanoparticles and have been evidenced to strongly depend on the nature of the cap as well as on the size of the nanoparticles. These results suggest that both the morphological and optical properties of noble metal nanoparticles can be tuned by using capping-layer effects and by choosing capping materials with appropriate physicochemical and electronic properties. [ABSTRACT FROM AUTHOR]

The formation and growth of defects, including nanocavities and extended interstitial-type defects, created by helium implantation in silicon (50 keV, 7.1015 cm-2) in the temperature range of 100–550 °C has been investigated by grazing incidence small-angle x-ray scattering. We show that quantitative information can be obtained on the size distribution, shape dispersion (i.e., anisotropy and faceting versus the size), and depth profile of the nanocavities from the near surface to deeply buried regions up to 1 μm. It is thus demonstrated that low temperature implantations (<=200 °C) lead to the formation of spherical nanocavities with a heterogeneous depth distribution whereas implantations at high temperatures (>=300 °C) cause growth of the cavities, broadening of the size distribution, and size-dependent faceting leading to a size-dependent shape anisotropy. Furthermore, we show that the method allows to characterize the morphology (i.e., width and thickness) and the evolution of extended planar {113} defects created during the implantation process at high temperatures. [ABSTRACT FROM AUTHOR]

Nanocermet trilayered thin films consisting of silver nanoclusters sandwiched between two dielectric layers (the buffer and the cap) have been synthesized by ion-beam sputtering with an alternate deposition of the metal and the dielectric species. The influence of the amount of silver, the nature of the buffer and the cap (BN or Si3N4), and a time delay before the cap deposition on clusters morphology and repartition have been investigated by transmission electron microscopy. It has been observed that the clusters display truncated ellipsoidal shapes in which the height to diameter ratio H/D decreases as the amount of deposited silver increases. For a given amount of silver, this ratio is lower in the case of a Si3N4 cap, whatever the nature of the buffer. Two explanations are proposed to account for this “cap effect” on clusters morphology: the first one is based on a calculation of the H/D minimizing the surface free energy of the clusters embedded between the buffer and the cap; the second one holds on the shape relaxation of the coalesced nonequilibrium clusters towards their equilibrium shape with the buffer, this process occurring until clusters are fully covered with the cap. Because of the higher deposition rate of Si3N4 compared to BN, a Si3N4 cap would allow a less efficient reshaping and consequently lead to flatter clusters. This explanation is supported by the temporal evolution of clusters morphology and repartition observed during the time delay before deposition of the cap. The evolution of the spectral position of the surface-plasmon resonance (SPR) of the trilayers as a function of their structure has also been investigated by optical transmittance measurements. The influence of cluster morphology, as well as the nature of the buffer and the cap on the SPR spectral position are discussed. [ABSTRACT FROM AUTHOR]

Presents information on a study which investigated the structural and magnetic properties of iron-carbon nanocomposite thin films. Encapsulation of metallic nanoparticles; Experimental details; Results and discussion; Conclusions.

The nucleation and growth of extended defects generated by H implantation into Ge at different temperature range that result from delicate interplay between kinetic and dynamic effects are described.