Plenarvorträge - DPG-Tagungen

Dünne Schichten Montag
DS 7.2 Mo 11:45 HS 32
Growth and structure of phthalocyanine thin films on SiO2 and
octadecyltriethoxisilanes — •Dimas Garcia de Oteyza 1 , Esther
Barrena 1 , J. Oriol Ossó 2 , and Helmut Dosch 1,3 — 1 Max
Planck Institut für Metallforschung, 70569 Stuttgart, Deutschland —
2 Institut de Ciència de Materials de Barcelona CSIC, 08190 Bellaterra,
Spanien — 3 Institut für Theoretische und Angewandte Physik, Universität
Stuttgart, 70569 Stuttgart
A key element for the controlled growth of organic thin films is the
substrate, since the resulting structure depends on the delicate balance
between the substrate-molecule and the intermolecular interaction. The
functionalization of the surfaces by self assembling monolayers (SAMs) allows
tailoring the surface properties while preserving the morphology. We
have used AFM and X-ray diffraction techniques to study the growth and
structure of copper hexadecafluorophthalocyanine (F16CuPc) on SiO2
and on functionalized SiO2 by octadecyltriethoxisilanes (OTE). OTE is a
methyl terminated SAM with a lower surface energy than SiO2. F16CuPc
films grown on SiO2 are smooth and show good out of plane order with
very low mosaicity (0.015 ◦ ).Their (001) plane is oriented parallel to the
surface, with the molecules essentially upright. Films grown on OTE
show a dewetting structure consisting of big elongated crystallites up to
the size of microns. In spite of the morphological differences, the films on
OTE exhibit the same out-of-plane lattice parameter and low mosaicity.
In-plane X-ray measurements indicate that the domain size is larger for
the films on OTE compared to those on SiO2, in agreement with the
AFM images.
DS 7.3 Mo 12:00 HS 32
Effect of surface structure on hydrophobicity — •Phani Ayalasomayajula,
Yvonne Gerbig, and Henry Haefke — CSEM Swiss
Center for Electronics and Microtechnology, Inc., CH-2007 Neuchatel,
Switzerland
Super hydrophobic surfaces can lead to applications in various fields.
This work reports on a key feature of super hydrophobicity: the combined
effect of chemistry and surface topography. Using the sol-gel technique,
hydrophobic surfaces that are smooth and crack-free based on Poly[4,5 difluoro
2,2-bis (trifluoromethyl)-1,3 dioxole]-co-tetrafluoroethylene (TFE)
DS 8 Dünnschichtanalytik I
were grown on glass. These were characterized using contact angle testing,
UV-visible spectroscopy (UV-vis) and Fourier transform infrared
(FTIR) spectroscopy to determine their wettabilty, optical absorbance
as well as vibrational and stretching bands of the deposited films, respectively.
Besides being hydrophobic, the deposited films are oleophobic,
transparent with antireflective properties and hard. TFE films with
thicknesses ranging from 5 nm to 50 nm were deposited on nanostructured
chromium nitride coatings to investigate the combined effect of surface
topography and chemistry upon film hydrophobicity. It was found
that TFE coatings on a specific columnar growth structure formation of
chromium nitride lead to an increase in the contact angle from 120 o to
147 o. Surface properties of the films have been examined using scanning
electron microscopy (SEM) and energy dispersive X-ray analysis (EDX)
for morphology and elemental composition, respectively. The precise effect
of surface morphology and roughness is discussed.
DS 7.4 Mo 12:15 HS 32
AFM investigation of oligophenyl thin films on crystalline substrates
— •G. Hlawacek 1 , C. Teichert 1 , S. Müllegger 2 , A. Winkler
2 , R. Resel 2 , S. Berkebile 3 , and M. Ramsey 3 — 1 Department
of Physics, University of Leoben, A-8700 Leoben, Austria — 2 Department
of Solid State Physics, Graz Technical University, A-8010 Graz, Austria
— 3 Department of Experimental Physics, University of Graz, A-8010
Graz, Austria
Crystalline films of conjugated organic semiconductors as parasexiphenyl
(PSP, C36H26) and para-quaterphenyl (PQP, C24H18) offer
attractive potential for optoelectronic applications. Here, Atomic
Force Microscopy (AFM) is used to investigate the nanometer-scale
morphology of PQP on various gold substrates and PSP on TiO2(110).
These oligophenylens can form complex arrays of three-dimensional
crystallites, where the long axis of the molecules are nearly parallel to
the surface. The orientation of these arrays is controlled by the geometry
of the substrate surface. On polycrystalline gold and TiO2(110) we could
also observe terrace structures composed of upright standing molecules.
Growth hillocks – consisting of several such layers – and crystallites coexist
within close proximity.
Zeit: Montag 14:30–15:15 Raum: HS 32
Hauptvortrag DS 8.1 Mo 14:30 HS 32
Electron holography — •Hannes Lichte — Institut fuer Strukturphysik,
TU Dresden, 01062 Dresden
Today, the performance of transmission electron microscopy (TEM)
is well developed to a resolution limit of close to 0.1nm; in particular
since the recently successful correction of spherical aberration of electron
lenses, the interpretability of electron images allows quantitative analysis
of most interesting structures, e.g. at defects and interfaces. Nevertheless,
a conventional electron microscope is still a poor phase contrast micro-
DS 9 Dünnschichtanalytik II
scope, i.e. it is virtually blind for pure phase structures such as electric
or magnetic fields. Electron holography has overcome this blindness: by
superposition of a reference wave on the object wave, a hologram is produced,
from which the phase structure of the object wave can quantitatively
be determined. This allows access to electric and magnetic fields,
from mesoscopic to atomic dimensions, as well as the determination of
atom species in compound specimen. Recent applications in the field of
nanomagnetics, dopant profiling in semiconductors, and in ferroelectrics
show the state of the art and the limits of the holographic method.
Zeit: Montag 15:15–17:15 Raum: HS 32
DS 9.1 Mo 15:15 HS 32
Untersuchung der Titan-Koordination in strukturell modulierten
Einkristallen und Gläsern der Zusammensetzung A2TiX2O8
(mit A = Ba, Sr und X = Si, Ge) — •Thomas Höche 1 , Frank
Heyroth 2 , Ralf Keding 3 und Peter van Aken 4 — 1 Leibniz-
Institut für Oberflächenmodifizierung e.V., Permoserstraße 15, D - 04318
Leipzig, Germany — 2 Interdisziplinäres Zentrum für Materialwissenschaften,
Martin-Luther-Universität Halle-Wittenberg, Hoher Weg 8, D -
06120 Halle a.d. Saale, Germany — 3 Otto-Schott-Institut für Glaschemie,
Friedrich-Schiller-Universität, Fraunhoferstraße 6, D - 07743 Jena, Germany
— 4 Institut für Angewandte Geowissenschaften, Technische Universität
Darmstadt, Schnittspahnstraße 9, D - 64287 Darmstadt, Germany
Kristalline Titanate mit der Fresnoitstruktur (Ba2TiSi2O8, Sr2TiSi2O8
und Ba2TiGe2O8) enthalten ausschließlich fünffach koordiniertes Ti 4+ .
Für das Verständnis des Kristallisationsverhaltens ist die Bestimmung
der Titan-Koordination in Schmelzen identischer Zusammensetzung es-
sentiell. Durch Quenchen der Schmelzen wurden Gläser erhalten, die anschließend
in einem Rastertransmissionselektronenmikoskop untersucht
wurden. Aus Elektronenenergieverlustspektren (spektrale Auflösung: ca.
0,4 eV) kann die Koordination von Übergangsmetallen bestimmt werden.
Dies wird anhand der Ti-L2,3-Ionisationskantenfeinstruktur von Gläsern
der Zusammensetzung Ba2TiSi2O8, Sr2TiSi2O8 und Ba2TiGe2O8 gezeigt
und die Ergebnisse werden mit früheren integralen Messungen (XPS,
XANES) der Titan-Koordination in Gläsern verglichen und den Kantenfeinstrukturen
der Einkristalle gegenübergestellt.
DS 9.2 Mo 15:30 HS 32
Diffraction patterns of modulated permutation twins —
•Ulrich Gebhardt 1 , P. Wochner 1 , A. Vigliante 2 , H.U. Habermeier
3 , and F. Razavi 4 — 1 MPI f. Metallforschung, Heisenbergstr.
3, 70569 Stuttgart — 2 Bruker AXS GmbH, Karlsruhe — 3 MPI f.
Festkörperforschung, Stuttgart — 4 Brock University, St. Catherines,
Ontario, Canada