162,115 research outputs found
Investigation of Structure and Growth of Self-Assembled Polyelectrolyte Layers by X-ray and Neutron Scattering under Grazing Angles
No full textThe structure of self-assembled polyelectrolyte thin films on float glass has been investigated by interface sensitive X-ray and neutron scattering methods. Special emphazis was given to the adsorption process of poly (ethylene imine) and polystyrole sulfonate as an important model system which is often used as a basis for subsequent multilayer buildup. From complementary X-ray and neutron reflectivity data, the vertical film density profile was derived for various growth parameters, including kinetic effects of different adsorption times. In addition to specular reflectivity, we have for the first time employed nonspecular X-ray scattering to study lateral structure parameters in self-assembled polyelectrolyte films. Furthermore, the technique of time-resolved in situ X-ray reflectivity during film growth has been demonstrated and is discussed in view of its future potential
Characterization of roughness correlations in W/Si multilayers by diffuse x-ray scattering
No full textWe present diffuse, nonspecular x-ray measurements of the interface height-height self-correlations in an amorphous W/Si multilayer. The measurements have been performed in a scattering geometry that is placed out of the plane of reflection, giving access to a much larger range in parallel momentum transfer than in conventional nonspecular geometries. For the sample studied a logarithmic form of the correlation function is found
[Report to Chief J. E. Curry, by an unknown author #1]
No full textReport to Chief J. E. Curry, by an unknown author. The report contains a list of officers who gave depositions to the United States Attorney
[Report to Chief J. E. Curry, by an unknown author #2]
No full textReport to Chief J. E. Curry, by an unknown author. The report contains a list of officers who gave depositions to the United States Attorney
Non-specular X-ray scattering from thin films and multilayers with small-angle scattering equipment
No full textWe present measurements of non-specular X-ray scattering from rough interfaces at a dedicated small-angle scattering beamline that allows for very low divergence of the incident beam and therefore for high resolution close to the specularly reflected beam. A two-dimensional detector is used to measure the non-specular intensity both in and out of the plane of reflection. The method is exemplified by an Au single layer, an amorphous Nb/Al2O3 multilayer and an epitaxial GaAs/AlAs superlattice sample
Kinetic Roughness of Amorphous Multilayers Studied by Diffuse X-Ray Scattering
No full textWe apply the scattering geometry of grazing incidence and exit angles to study the diffuse scattering of an amorphous, magnetron sputtered W/Si multilayer. Only this technique allows for the full range of parallel momentum transfer necessary to determine the height-height self- and cross-correlation functions from the structure factor of the rough interfaces and the exit-angle-resolved intensity, respectively. The self-correlation functions show the logarithmic scaling behavior predicted by the Edwards-Wilkinson Langevin equation, which describes the kinetic roughening of a growing surface. The cross-correlation functions also agree with those derived from the equation
Elastic scattering under simultaneous excitation of x-ray standing waves in multilayers
No full textWe have measured the structure factor of diffuse scattering and amorphous scattering in a W/Si multilayer under simultaneous excitation of x-ray standing waves. The tuning of the nodes and antinodes to the location of the W and Si sublayers or to the respective interfaces increases the selective sensitivity to the structure of the respective sublayer or interface. The dynamically broadened first multilayer Bragg peak is modeled by the Darwin theory of dynamic diffraction, which allows for the exact determination of the standing wave phase. The decay of diffuse intensity, as measured in a grazing incidence geometry at different standing wave phase shifts, indicates that the height–height self-correlation function is of the same form for both types of interfaces, W/Si and Si/W. The amorphous peaks of the Si sublayer can only be observed if the angles of incidence and exit are optimized to suppress the scattering from the otherwise dominating W layers. The peak positions are the same as for bulk amorphous silicon
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