10 research outputs found
From atoms to layers: in situ gold cluster growth kinetics during sputter deposition
The adjustment of size-dependent catalytic, electrical and optical properties of gold cluster assemblies is a very significant issue in modern applied nanotechnology. We present a real-time investigation of the growth kinetics of gold nanostructures from small nuclei to a complete gold layer during magnetron sputter deposition with high time resolution by means of in situ microbeam grazing incidence small-angle X-ray scattering (μGISAXS). We specify the four-stage growth including their thresholds with sub-monolayer resolution and identify phase transitions monitored in Yoneda intensity as a material-specific characteristic. An innovative and flexible geometrical model enables the extraction of morphological real space parameters, such as cluster size and shape, correlation distance, layer porosity and surface coverage, directly from reciprocal space scattering data. This approach enables a large variety of future investigations of the influence of different process parameters on the thin metal film morphology. Furthermore, our study allows for deducing the wetting behavior of gold cluster films on solid substrates and provides a better understanding of the growth kinetics in general, which is essential for optimization of manufacturing parameters, saving energy and resource
Influence of Nanoparticle Surface Functionalization on the Thermal Stability of Colloidal Polystyrene Films
The installation of large scale colloidal nanoparticle
thin films
is of great interest in sensor technology or data storage. Often,
such devices are operated at elevated temperatures. In the present
study, we investigate the effect of heat treatment on the structure
of colloidal thin films of polystyrene (PS) nanoparticles in situ
by using the combination of grazing incidence small-angle X-ray scattering
(GISAXS) and optical ellipsometry. In addition, the samples are investigated
with optical microscopy, atomic force microscopy (AFM), and field
emission scanning electron microscopy (FESEM). To install large scale
coatings on silicon wafers, spin-coating of colloidal pure PS nanoparticles
and carboxylated PS nanoparticles is used. Our results indicate that
thermal annealing in the vicinity of the glass transition temperature <i>T</i><sub>g</sub> of pure PS leads to a rapid loss in the ordering
of the nanoparticles in spin-coated films. For carboxylated particles,
this loss of order is shifted to a higher temperature, which can be
useful for applications at elevated temperatures. Our model assumes
a softening of the boundaries between the individual colloidal spheres,
leading to strong changes in the nanostructure morphology. While the
nanostructure changes drastically, the macroscopic morphology remains
unaffected by annealing near <i>T</i><sub>g</sub>
P03, the Microfocus and Nanofocus X-ray Scattering (MiNaXS) beamline of the PETRA III storage ring: The microfocus endstation
The MiNaXS (P03) beamline of the new third-generation synchrotron radiation source PETRA III (DESY, Germany) has been designed to perform small-, ultra-small- and wide-angle X-ray scattering in both transmission and grazing-incidence geometries. The high photon flux available at the beamline enables time-resolved investigations of kinetic phenomena with a time resolution below 100 ms. The microfocus endstation started user operation in May 2011
Combining imaging ellipsometry and grazing incidence small angle x-ray scattering for an in-situ characterization of polymer nanostructures
A combination of microbeam grazing incidence small angle X-ray scattering (muGISAXS) and imaging ellipsometry is introduced as a new versatile tool for the characterization of nanostructures. muGISAXS provides a local lateral and depth-sensitive structural characterization, and imaging ellipsometry adds the position-sensitive determination of the three-dimensional morphology in terms of thickness, roughness, refractive index, and extinction coefficient. Together muGISAXS and imaging ellipsometry enable a complete characterization of structure and morphology. On the basis of an example of buildup of nanostructures from monodisperse colloidal polystyrene nanospheres on a rough solid support, the scope of this new combination is demonstrated. Roughness is introduced by a dewetting structure of a diblock copolymer film with one block being compatible with the colloidal nanoparticles and one block being incompatible. To demonstrate the potential for kinetic investigations, muGISAXS and imaging ellipsometry are applied to probe the drying process of an aqueous dispersion of nanospheres on such a type of rough substrate