Dresden 2003 – wissenschaftliches Programm

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O: Oberflächenphysik

O 27: Organische Dünnschichten I

O 27.2: Vortrag

Donnerstag, 27. März 2003, 11:30–11:45, HSZ/02

Determination of Adsorption Geometry of Single SnPc Molecules by STM — •Markus Lackinger and Michael Hietschold — Chemnitz University of Technology, Institute of Physics, Reichenhainerstr. 70, 09107 Chemnitz, Germany

VT-STM under UHV conditions was applied to study the adsorption behavior of the non-planar molecule tin-phthalocyanine(SnPc) on a Ag(111) single crystalline surface. For submonolayer coverage, deposited on a room temperature substrate, the coexistence of a disordered and an ordered phase was found. The disordered phase showed short range ordering in terms of molecular chains and agglomerates. For the ordered phase a rectangular unit cell with a two-molecular base was found.

Submolecularly resolved images allow one to distinguish between two different adsorption states of the shuttlecock shaped molecule. In these states the central Sn-atom was pointing either towards or off the surface. In case of the densely packed phase an azimuthal rotation of the "upNo-dq and No-dqdownNo-dq adsorbed molecules enables a high packing density. Furthermore, an attempt of deducing the energy difference for the two adsorption states was made by statistical analysis of the STM data. On the other hand, for SnPc layers on HOPG(0001) only a single adsorption state could be found.

Surf.Sci. 520 (2002) L619-L624