Influence of roughness profile on reflectivity and angle-dependent X-ray fluorescence

The theory of X-ray scattering from rough interfaces using the second-order distorted-wave Born approximation is reviewed. For specular reflectivity a new expression is given which smoothly connects the Névot-Croce and Debye-Waller expressions. The shape, of the reflectivity curve depends not only on the average roughness, but also on the lateral correlation of the roughness profile. Using the same theory, the several ways in which roughness can influence angle-dependent X-ray fluorescence are evaluated. Finally, possible shapes for the roughness correlation function are discussed

Application of genetic algorithms for characterization of thin layered materials by glancing incidence X-ray reflectometry

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Specular and non-specular X-ray reflection from inorganic and organic multilayers.

Specular and non-specular X-ray reflectivity measurements can be exploited to obtain interesting properties of layered materials such as electron-density profile and lateral and perpendicular structure of interface roughness. This will be illustrated using results on a nickel–carbon multilayer and a liquid-crystalline polymer

Order in thin films of side-chain liquid-crystalline polymers.

Spin-coated side-chain liquid-crystalline polymer films, based on alternating copolymers of maleic anhydride and -olefins carrying terminal mesogenic methoxybiphenylyloxy groups, on silicon wafers show lamellar ordering upon annealing above the glass transition temperature. In the surface topography (atomic force microscopy measurements), structures are visible with a height corresponding to a bilayer. Also within the film, the side chains are ordered perpendicularly to the surface as measured by X-ray reflectometry. There are indications that directly at the substrate surface the side chains are aligned parallel to the surface. By the two complementary techniques, a rather complete picture is obtained. Even though the films are very thin (nanometer-scale thickness), the structure has a high degree of perfection and the bilayer spacing is the same as measured for bulk polymer