Surface sensitive x-ray scattering studies were carried out to understand the morphology of cermet thin films prepared by cosputtering metallic gold and ceramic materials on float glass substrates. It has been observed that the morphology of Au clusters in cermet thin films depends strongly on the matrix during growth, even if, all other conditions are kept identical. In particular, nearly isotropic growth of Au clusters, to form nanoparticles, is found in silica and alumina matrices, while anisotropic columnar-like growth of Au clusters, to form a nanorod-like shape, is found in a titanium oxide matrix. Thickness of the films was also found very different, which is likely to be related to the different sputtering yields of the ceramic materials. The volume fraction of Au estimated from the electron density profile shows that the total volume or the amount of Au is different in films of different ceramic matrices. This suggests that even the sputtering yield of Au is very different in the presence of different ceramic atmosphere, which is likely to be responsible for having a different morphology of Au clusters in different matrices. Optical absorption spectra of the films, on the other hand, show linear dependence of the absorption peak position with the volume fraction of Au and independent of both the ceramic matrix and morphology of Au clusters.

Investigations of thickness induced percolation process in Ptξ–Al2O3 nano-composites were carried out using grazing angle X-ray scattering. It is shown that the morphological characteristics of the nano-scaled Pt particles change significantly within the growth transversal direction. The initially non percolated two phases Ptξ–Al2O3 nano-composites show a noteworthy tendency to a percolated morphology with a gradual transversal increase of Pt nano-particles' average diameter in addition to the increase of the Pt nano-particles' poly-dispersity. This transversal morphological evolution is followed by a percolation phenomenon of the Pt nano-particles for a thickness of about ∼119.5nm. This transversal morphological evolution seems to corroborate far too much with a columnar growth process.

Room temperature magneto-optical and radar absorption measurements were carried out on Feξ–V2O5 nano-composites prepared by RF co-sputtering. The relationship between the Fe atomic content and the state of the matrix precursor as well as the metal nano-particles’ size are discussed with emphasis on the interfacial oxidation of the Fe nano-particles. The magneto-optical and radar absorption responses were found to be effective above the Fe nano-particles percolation threshold ξC. Using three different complementary techniques, this critical value was found to be about 23% atomic. From absorption viewpoint, these Feξ–V2O5 nano-composites could be adequate radar absorbers at the specific radar frequency of 9.45GHz. Below the critical atomic concentration value of 23%, the radar absorption is weak and relatively broad.

A new class of nano-photonics for possible χ3(ω) applications have been synthesized by pulsed laser ablation and optically characterized. Compared to standard nano-composites exhibiting an exalted effective χ3(ω) due to the enhancement of the local electric field, these Au–VO2 nano-composites display an additional reversibly tunable surface plasmon frequency under external temperature stimuli. This is due to the semi-conducting/metallic first order transition of the host VO2 matrix. The nano-gold surface plasmon wavelength shifts reversibly from 645 to 598nm when the Au–VO2 nano-composites temperature varies from 25 to 120°C. Even if the spectral shift is not extensively large, such a tunability is positively genuine.

Temperature morphological evolution of nonpercolated granular nano-structures of platinum nano-particles embedded in an insulating alumina matrix was investigated by X-rays scattering in grazing angle reflection mode. In the investigated temperature range of 298–823 K, it was found that the annealing treatment tends to increase the Pt nano-particles' size and to produce a quasi-mono-disperse Pt nano-particles followed by a reduction of the barrier thickness between them. The percolation temperature is estimated to be of the order of 890 K. Using the rate constant governing the growth of the Pt nano-particles, the corresponding activation energy was determined to be about 90 kJ/mol.

Irradiation of polycrystalline sputter-deposited ITO thin films on float-glass substrates was performed with high-energy MeV He+ ion beam implantation at doses in the range 2–6×10+15ions/cm2. A significant change in both surface morphology and crystallographic structure after implantation was observed. It results in a crystallographic disorder of large crystallites with the ion dose, creation of electronic defects and a roughening of the ITO thin-films’ surface.

A new type of photo-active nano-composite material appropriate for Ultra-fast Nonlinear Optical χ(3) (ω) applications has been synthesized and optically characterized. Compared to standard noble metal particles- oxide nano-composites exhibiting a superior effective χ(3) (ω) due to the enhancement of the local electric field, these Au−VO2 nano-composites display an additional reversibly tunable surface plasmon frequency under external temperature stimuli. Such a smart plasmon tunability is correlated to the Mott’s type semiconducting/metallic 1st order transition of the host VO2 matrix. The nano-gold surface plasmon wavelength shifts reversibly from 645 nm to 598nm when the Au−VO2 nano-composites temperature varies from 25°C to 120°C.

The morphology of Au–Al2O3 nanocermet thin films, prepared by cosputtering Au and Al2O3 on float glass substrates, was studied using surface sensitive x-ray scattering techniques and the results were correlated with the optical absorption of the films measured using ultraviolet visible spectroscopy. The presence of gold nanoparticles in an alumina matrix is evident from both x-ray scattering and spectroscopic studies. The distribution of nanoparticles is obtained from grazing incidence small angle x-ray scattering, while the electron density profile obtained from the analysis of x-ray reflectivity data gives total film thickness, volume fraction (f) of Au and the special arrangement along the growth direction. Optical properties show a linear dependence of the absorption peak position with f, which is interesting for making nanocomposites of tunable absorption.

The morphology of nanocermet thin films deposited on substrates having different roughnesses has been studied by surface sensitive x-ray scattering techniques. Grazing incidence small angle scattering data of the films shows that the nanoparticles, which are present in the ceramic matrix, exhibit a specific average interparticle separation. Analysis of the x-ray reflectivity indicates that, in the films deposited on smooth substrates, the nanoparticles adopt some layering along the growth direction. This layering tends to diminish with increasing substrate roughness and vanish completely for very high substrate roughness. The variation of such layering with substrate roughness is an indication that it starts close to the substrate and is an effect of the substrate boundary condition.

Experiments performed by x-ray reflectivity, grazing incidence small angle x-ray scattering (GISAXS), and transmission electron microscopy (TEM) on a cosputtered nanocermet thin film of Pt-Al2O3 are presented. It is shown that the morphology of such a heterogeneous material can be well interpreted by combining the information obtained from the three techniques. In particular, the layering of metal nanoparticles in the immediate vicinity of the substrate is clearly evidenced. GISAXS results are interpreted via a model which yields spherical nanoparticles of diameter 2R=3.1 nm, separated on the average by a distance of 5.8 nm. The evidence for the layering of particles close to the substrate is deduced from the analysis of the specular reflectivity and probed directly by TEM.

Ag-TiO(2) nanocermet thin films, deposited for optical filtering applications by two sputtering techniques, codeposition and multilayer deposition, exhibit surface plasmon absorption in the spectral range 450-500 nm. The cosputtering technique induces a columnar growth, whereas multilayer deposition produces a more-random distribution of silver inclusions. Both films have large, flat silver grains at the air-cermet interface. An optical double-heterogeneous layer model based on the experimental morphological parameters of the films accounts well for their experimental transmittance, notably for extra absorption near 700 nm, which is attributed to a surface plasmon in the flat silver grains of the surface.

The optical properties of Ag-TiO2 nanocermet thin films are studied with the aim of optical filtering applications. Beyond the classical properties of cermets with noble metal inclusions predicted by the effective medium theories, the optical properties of Ag-TiO2 nanocermets deposited by R.F. cosputtering are governed by their columnar morphology and the under-stoichiometry of the TiO2 matrix. A careful experimental analysis of the different parameters and effects involved in the optical response of these nanocermets is performed both on TiO2 and Ag-TiO2: film thickness, silver volume fraction, thermal treatments, oxidation. The influence of these parameters on the surface plasmon resonance and the infrared transmission of the nanocermet thin films is optimized.

Third-order nonlinear optical properties of Au:SiO2 thin films were studied at the surface plasmon resonance wavelength by the z-scan technique using a nanosecond laser. Films were prepared by a multilayer deposition sputtering technique. They were composed of 2 nm mean diam gold particles, with a metal volume fraction of 20%. Z-scan measurements performed both with and without aperture showed a very large nonlinear absorption masking the nonlinear refraction. The nonlinear absorption coefficient β was found to be negative and equal to −1.1×10−2 cm/W. The different mechanisms contributing to this absorption are discussed and the large value of β is correlated to the duration of the laser pulses. Moreover, it is shown that a mean field theory is not appropriate to evaluate the effective susceptibility at high metal concentrations.

Granular Fe-V2O5 thin films with different iron concentrations prepared by means of radiofrequency magnetron co-sputtering technique were investigated by means of X-ray; diffraction, Transmission Electron microscopy and Fe-57 Mossbauer spectrometry as a function of iron concentration. A common experimental feature reveals that a percolation-like threshold occurs at around 23-25% atomic Fe. Below such a critical value, the co-sputtering process favours the presence of ultrafine amorphous oxide grains with sizes lower than 10 nm embedded in a vanadium oxide matrix. Above, one clearly observes the presence of fine grains (sizes comprised between 10-100 nm) composed of either hematite or maghemite phases dispersed in the same matrix, the set displaying a magnetic order at room temperature.

The influence of matrix and substrate on the morphology of three Pt nanocermet thin films has been studied by transmission electron microscopy (TEM), X-ray specular reflectivity and secondary ion mass spectrometry (SIMS). The TEM measurements clearly evidence the presence of metallic nanoparticles inserted in an amorphous insulator matrix. The structure of the thin films in the z-direction, normal to the surface of the films, is then analysed by specular X-ray reflectivity. Using two different models to analyse the data, it is shown that although the size and the mean separation of the particles does not depend much on the nature of the insulator matrix, the substrate and the insulator matrix play; a key role at the film-substrate interface. These conclusions are reinforced by the SIMS analysis which shows that the diffusion of metallic particles in the substrate is important in the presence of alumina matrix.

Optical response of TiO 2 layers, prepared by R.F. sputtering from TiO 2 target, was studied as a function of target state, oxygen partial pressure and sputtering power. We have found that TiO 2 layers deposited from a used target exhibit a high absorptance which decreases greatly when an oxygen partial pressure is introduced. Whereas an increase of sputtering power leads to an absorbent TiO 2 matrix.

Thermal stability of multilayered Co–Ti neutron optic polarizers with a period of the order of 103Å is investigated. The diffusion kinetics is determined by using the Du Mond and Youtz's method with grazing angle neutron reflectometry in the temperature range of 293–723K. It was found that the diffusion is mainly directed from Co-layers towards the Ti-layers. The effective interdiffusion coefficient Deff of cobalt into titanium is calculated from the rate of decrease of the first reflected Bragg peak related to the artificial periodicity of the multilayer with the annealing temperature T. The temperature dependence of Deff is found to be described approximately by Deff≈(D0 exp (−0.25eV/kBT)) cm2s−1.

It is shown here that the observation of the phenomenon of like small angle scattering of X-rays in very thin heterogeneous films, can be made comparatively easily by using grazing angle reflectometry of X-rays. The feasibility was achieved with co-sputtered thin films of approximately 600 Å thickness, made up by crystalline platinum clusters embedded in an amorphous alumina matrix. The experimental reflectivity profiles are simulated by the intensity superposition of two components: (i) the specular part caused by the usual interference phenomenon between the partial waves reflected from the air-film and film-substrate interfaces, and (ii) the like-small angle scattering part due to diffraction by platinum clusters. It is found that the shape of such clusters is spherical characterized by mean values of diameter \(\) and inter-cluster distance \(\) of the order 29 Å and 45 Å respectively with standard deviations \(\) and \(\) of the order of 3 Å. Such an observation of both the interference and diffraction phenomena indicates that the thin granular film exhibits both its continuous and heterogeneous aspects together.