IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Organic Films and Devices Thursday Sessions
       Session OF+TF-ThP

Paper OF+TF-ThP4
Mobility, Binding Transition and Ordering of C@sub 60@ on Pd(110): Investigations at the Local and Mesoscopic Scale

Thursday, November 1, 2001, 5:30 pm, Room 134/135

Session: Aspects of Organic Films Poster Session
Presenter: J. Weckesser, Max-Planck-Institut fuer Festkoerperforschung, Germany
Authors: J. Weckesser, Max-Planck-Institut fuer Festkoerperforschung, Germany
C. Cepek, Laboratorio Nazionale TASC-INFM, Italy
R. Fasel, Swiss Federal Laboratories for Materials Testing and Research, Switzerland
J.V. Barth, Ecole Polytechnique Federale de Lausanne, Switzerland
T. Greber, Universitaet Zuerich, Switzerland
J. Osterwalder, Universitaet Zuerich, Switzerland
K. Kern, Max-Planck-Institut fuer Festkoerperforschung, Germany
Correspondent: Click to Email
We present a comprehensive study of C@sub 60@ on a Pd(110) surface using scanning tunneling microscopy (STM), low-eneregy electron diffraction (LEED), x-ray photoelectron spectroscopy and diffraction (XPS and XPD). The mobility and interactions of C@sub 60@ on a Pd(110) surface have been characterized by variable temperature scanning tunneling microscopy. The motion of isolated C@sub 60@ molecules was directly monitored and the corresponding tracer diffusion barrier was determined to (1.4±0.2) eV. Upon annealing to 700 K the C@sub 60@ molecules undergoe an irreversible bonding transition resulting in a second, more strongly bound C@sub 60@ species. This is associated with a local substrate reconstruction whereupon C@sub 60@ molecules sink into the formed microscopic pits. The rearrangement of Pd substrate atoms turns out to play a crucial role similarly in the formation of C@sub 60@ thin films. In STM three well-ordered structures consisting of alternating dark and bright molecular rows are found, in combination with LEED and XPS their real space structures are determined. The height difference in STM is attributed to a local reconstruction of the Pd substrate. Whereas the C@sub 60@ molecules of the bright molecular rows are adsorbed in one layer deep microscopic pits, C@sub 60@ accommodated in two layer deep pits account for the dark molecular rows. XPD results complete the understanding of the film structure and reveal the orientation of the C@sub 60@ cages.