Dresden 2009 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 44: Metal substrates: Adsorption of organic / bio molecules VI

O 44.7: Vortrag

Donnerstag, 26. März 2009, 12:00–12:15, SCH A118

PTCDA induced faceting of a vicinal Ag(111) surface: an in-situ LEEM study — •Thomas Schmidt¹, Florian Pollinger², Helder Marchetto¹, Stefan Schmitt², Florian C. Maier², Alessandro Sala¹, Friedrich T. Reinert², Eberhard Umbach^2,3, and Hajo Freund¹ — ¹Fritz-Haber-Institut, Abt. CP, 14195 Berlin — ²Universität Würzburg, EP II, 97074 Würzburg — ³Forschungszentrum Karlsruhe, 76021 Karlsruhe

Adsorption of organic molecules on vicinal metal surfaces is known to promote faceting and self-organized ordering on mesoscopic scales[1]. In the temperature range between 400 K and 620 K the adsorption of PTCDA on a Ag(10 8 7) surface has been studied in-situ and in real-time by LEEM (low energy electron microscopy) and LEED, using the SMART microscope[2]. The deposition of one organic layer leads to grating-like structures. The direct observation reveals a two-step process: first, facets with an angle of ca. 25° inclination are formed with (111) orientated areas in between, whereas only the facets are covered by PTCDA. In a second step the bare (111) areas are covered by PTCDA, forming a complete monolayer. The temperature dependence of the structure sizes and the influence of inhomogeneity in the initial substrate step density are discussed.

[1] S. Schmitt, Dissertation Würzburg, 2007.

[2] R. Fink et al. J. Electr. Spectrosc. Rel. Phen. 84 (1997) 231-250.