X-ray Scattering Study of Nanostructured GaSb Surfaces
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- Institutt for fysikk 
In this thesis the surface structure of a sample consisting of slightly tilted, denselypacked Gallium-Antimonide (GaSb) nanocones, self-assembled through Ion Beam Sputtering(IBS) is investigated with a selection of X-ray methods. The main method usedis Grazing-Incidence Small-Angle X-ray Scattering (GISAXS), the results of which areanalyzed in combination with simulations made with IsGISAXS. Additionally, complementaryinvestigations with X-ray Reflectivity (XRR) and Grazing-Incidence Wide-AngleX-ray Scattering (GIWAXS) are done.GISAXS measurements of four orientations of the sample around the sample normalrevealed an asymmetry in the cone shape for two of the orientations. The asymmetry wasascribed to a small tilt of the cones. Moreover, the spacing between the cones was foundto vary between the orientations exhibiting a symmetric- and the orientations exhibitingan asymmetric scattering pattern.Simulations showed that the effect of the correlation between the shape- and positionof the scatterers is small, making it possible to determine the cone spacing withoutknowing the cone height, cone radius or base angle. One of the orientations exhibitinga symmetric scattering pattern was chosen for comparison to the IsGISAXS simulationsand the cone spacing for this orientation was determined to be d = (40 ± 2) nm.A previously performed s-MME study of the sample reported the height of the conesand top- and bottom diameters defined relative to the mean cone spacing. These valueshave been combined with the cone spacing found with GISAXS to give a bottom diameterD1 = (40 ± 2) nm, top diameter D2 = (1.6 ± 0.1) nm and a base angle of 64 degrees.Investigations of the macroscopic variations of the in-plane structure of the samplerevealed an increased uncertainty in the cone spacing towards one of the edges.The GIWAXS results together with simulations made with SimDiffraction showedthat the sample mainly consists of single crystalline GaSb, with some polycrystallinedomains.