Search results for "Grazing-incidence small-angle scattering"
showing 10 items of 10 documents
From Spherical Mesopores to Worm-Shaped Mesopores : Morphology Transition in Titania–Polystyrene-b-poly(ethylene oxide) Composite Films with Increasi…
2013
A morphology transition from spherical mesopores to worm-shaped mesopores within titania block copolymer composite thin films has been observed by varying the sol–gel reaction time from 40 min to 48 h in the four-component templating system of polystyrene-$\mathit{b}$-poly(ethylene oxide) (PS-$\mathit{b}$-PEO), 1,4-dioxane, concentrated HCl, and titanium tetraisopropoxide (TTIP) with a PS-$\mathit{b}$-PEO mass concentration of 0.25 wt.-%. The impact of the sol–gel reaction time on the local structure, long-range lateral structure, and vertical structure of the as-prepared, calcined, and UV-degraded thin films as well as the structural changes in solution have been systematically investigate…
Treatment of grazing-incidence small-angle X-ray scattering data taken above the critical angle
2001
The equations taking into account refraction at the sample surface in grazing-incidence small-angle X-ray scattering (GISAXS) when the angle between the incoming beam and the sample surface is slightly larger than the critical angle are derived and discussed. It is demonstrated that the refraction of both the incoming and the scattered beam at the sample surface affects the GISAXS pattern and that, when a planar bidimensional detector perpendicular to the incoming beam is used, the effect depends on the azimuthal detector angle. The smearing of the pattern depending on the size of the illuminated sample area in grazing incidence is estimated by simulations with Cauchy functions of different…
Influence of metal–support interaction on the surface structure of gold nanoclusters deposited on native SiOx/Si substrates
2014
The structure of small gold nanoclusters (R ~ 2.5 nm) deposited on different silica on silicon substrates is investigated using several characterization techniques (AFM, XRD, EXAFS and GISAXS). The grain morphology and the surface roughness of the deposited gold clusters are determined by AFM. The in-plane GISAXS intensity is modelled in order to obtain information about the cluster size and the characteristic length scale of the surface roughness. AFM and GISAXS results are in excellent agreement and show that the surface morphology of the deposited clusters depends on whether defect-rich (native) or defect-free (thermal) silica is used as a substrate. Gold clusters show a strong tendency …
Morphology evolution in mesoporous titania block copolymer composite films with increasing Sol-Gel reaction time
2013
A morphology evolution of thin films of titania from spherical mesopores to worm-shaped mesopores was realized by simply varying the sol–gel reaction time from 46 min to 25 h in the quadruple system consisting of polystyrene–block-poly(ethylene oxide) (PS–b-PEO), 1,4-dioxane, concentrated HCl, and titanium tetraisopropoxide (TTIP). Imaging techniques including scanning electron microscopy (SEM) and atomic force microscopy (AFM) were applied to investigate the local structure change of the as-prepared, calcined, and UV-degraded composite films. Grazing incidence small angle X-ray scattering (GISAXS) experiments prove that the structure change in local areas is representative of that over the…
Double implantation in silica glass for metal cluster composite formation: a study by synchrotron radiation techniques
2001
Silica glass containing metal clusters is studied for both basic and applied aspects, related to the physics of cluster formation and to the optical properties of these materials. To obtain such composite structure, Cu+ Ni, Au+ Cu, Au+ Ag, Cu+ Co, and Cu+ Ag sequential implantations in fused silica were realized. The resulting systems, after possible annealing in various atmospheres, were studied by synchrotron radiation-based techniques, namely, extended X-ray absorption fine structure (EXAFS) spectroscopy, grazing incidence X-ray diffraction (GIXRD), and grazing incidence small angle X-ray scattering (GISAXS). The unique potential of these techniques is the capability to investigate dilut…
Light scattering in opal heterojunctions
2006
Light propagation in photonic hetero-crystals, consisting of two opal films with different lattice constants, has been investigated in the realistic regime of weak scattering, when the main light flux is transported by ballistic photons. The light scattering at the photonic bandgap interface is studied in combination with transmission data. The spectra and directionality diagrams of scattered light of single- and hetero-opal films are compared. The rate of decrease of the scattering intensity as a function of the scattering angle has been used to quantify the scattering strength. The anisotropy of the interface scattering is identified by deducing the trajectories of single scattered photon…
On the use of grazing-incidence small-angle X-ray scattering (GISAXS) in the morphological study of ion-implanted materials.
2004
Grazing-incidence small-angle X-ray scattering has become a widely used technique for the morphological analysis of surface systems. Here it is show how this technique can be applied to a buried system, like metallic clusters in glass obtained by ion implantation. The optimization of the data-collection geometry is described as well as the details of the quantitative data analysis. An experimental example on Cu + Au-implanted glasses shows the potentiality of the technique.
Light transport in hetero-opal photonic crystals
2005
The effect of photonic bandgap interface upon the light scattering was studied in hetero-opals consisting of two opal thin films with different lattice constant. It is shown that the weak scattering regime is preserved in thin hetero-opal films. By comparing scattering spectra of single and hetero-opal films recorded under reversing angles of light incidence and detection it was demonstrated that the interface scatters stronger the light at oblique incident angles. Squeezing of the scattering diagram of hetero-opals compared to single opal films is also assigned to the interface scattering.
Study on the initial stages of water corrosion of fluorozirconate glasses
2004
Abstract The surface corrosion process associated with the hydrolysis of fluorozirconate glass, ZBLAN (53ZrF 4 , 20BaF 2 , 20NaF, 4LaF 2 , 3AlF 3 ) was investigated using X-ray photoelectron spectroscopy (XPS), grazing-incidence small angle X-ray scattering (GISAXS), X-ray reflectivity (XRR) and scanning electron microscopy (SEM). After a short exposure period (25 min) of the glass surface to deionized water the XPS data indicate an increase of the oxygen content accompanied by a decrease of fluorine concentration. The analysis of the chemical bonding structure identified the predominant surface reaction products as zirconium hydroxyfluoride and oxyfluoride species. The second most abundant…
Hierarchically Structured Titania Films Prepared by Polymer/Colloidal Templating
2010
Hierarchically structured titania films for application in hybrid solar cells are prepared by combining microsphere templating and sol-gel chemistry with an amphiphilic diblock copolymer as a structure-directing agent. The films have a functional structure on three size scales: (1) on the micrometer scale a holelike structure for reduction of light reflection, (2) on an intermediate scale macropores for surface roughening and improved infiltration of a hole transport material, and (3) on a nanometer scale a mesoporous structure for charge generation. Poly(dimethyl siloxane)-block-methyl methacrylate poly(ethylene oxide) (PDMS-b-MA(PEO)) is used as a structure-directing agent for the prepara…