Regensburg 2013 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 27: Thin Film Characterization: Structure Analysis and Composition (XRD, TEM, XPS, SIMS, RBS,...) I
DS 27.7: Vortrag
Mittwoch, 13. März 2013, 18:45–19:00, H32
X-ray Grazing Incidence Diffraction from OTS-SAMs on Metal Oxides — •Hans-Georg Steinrück1, Stefan Gerth1, Michael Klimczak1, Moshe Deutsch2, Ben Ocko3, and Andreas Magerl1 — 1Lehrstuhl für Kristallographie und Strukturphysik, Universität Erlangen Nürnberg , Germany — 2Bar-Ilan University, Ramat-Gan, Israel — 3Brookhaven National Laboratory, Upton NY, USA
We investigated the in-plane structural properties of octadecyltrichlorosilane (C17H37Cl3Si, OTS) self-assembled monolayers on amorphous SiO2, quartz (001) and sapphire (001) via X-ray grazing incident diffraction.
For all three systems a powder like diffraction ring at qr=1.50Å−1 was found. The radial width of these peaks corresponds to a coherence length of about 4 OTS molecular diameters, which fits well with the findings of Tidwell et al. for OTS monolayers on amorphous SiO2 [1].
For OTS on sapphire the azimuthal scans show increasing peak intensities towards the sapphire in-plane peak, suggesting orientational order of the OTS film which is likely related to the good lattice match with the sapphire. This epitaxial behavior depends on the headgroup properties of hydrocarbon chain monolayers, as Ocko et al. have shown perfect commensurabiltiy for C18H37OH on sapphire [2].
Further the temperature dependence of the lateral structure was investigated yielding a decreasing intensity and an increasing lattice spacing with increasing temperature for all three systems.
[1] Tidswell et al., J. Chem. Phys. 95, 2854 (1991)
[2] Ocko et al., Phys. Rev. Lett. 106, 137801 (2011)