Regensburg 2010 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 22: Synthesis of Nanostructured Films by Self-organization II (Focused Session)

DS 22.5: Topical Talk

Mittwoch, 24. März 2010, 17:15–17:45, H2

Self-organization and molecular diffusion processes in organic thin film growth — •Christian Teichert — Institute of Physics, University of Leoben, A-8700 Leoben, Austria

Crystalline films of conjugated organic semiconductors offer attractive potential for optoelectronic and electronic applications on flexible substrates. Due to the complexity and anisotropy of the molecular building blocks, novel growth mechanisms can occur as is demonstrated for the growth of the rod-like oligophenylene molecule parasexiphenyl (6P) on mica surfaces. On clean mica(001), the self-organization of crystallites into one-dimensional chains is observed on a wetting layer where the 6P molecules lie on the surface [1]. However, if the mica surface is amorphized by gentle bombardment with 500 eV Ar⁺ ions, the formation of terraced mounds composed by almost upright standing molecules is found by atomic force microscopy. Quantitative analysis of the morphology together with transition state theory calculations revealed the existence of level dependent step edge barriers [2]. A lower barrier due to less molecular tilt in the first layer results in the completion of one monolayer before mound formation starts.

[1] C. Teichert, et al., Appl. Phys. A 82 (2006) 665. [2] G. Hlawacek, P. Puschnig, P. Frank, A. Winkler, C. Ambrosch-Draxl, C. Teichert, Science 321 (2008) 108.

This work has been performed in collaboration with G. Hlawacek, Q. Shen, S. Lorbek, P. Puschnig, C. Ambrosch-Draxl, P. Frank, and A. Winkler. Support by the Austrian Science Fund (FWF) is acknowledged.