Dresden 2009 – scientific programme

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DS: Fachverband Dünne Schichten

DS 23: Organic Thin Films III

DS 23.3: Talk

Wednesday, March 25, 2009, 15:15–15:30, GER 38

Diindenoperylene on rutile TiO₂ (110) — •Britt-Elfriede Schuster, Maria Benedetta Casu, Heiko Peisert, and Thomas Chassé — Institute for Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 8, 72076 Tübingen, Germany

In order to optimize device performance, a comprehensive knowledge of the electronic, structural and morphological properties of organic materials is indispensable. In this regard, a crucial aspect in this field is the growth because the understanding of growth phenomena is extremely significant for many technical applications dealing with systems ranging from thin films to single crystals. Diindenoperylene (DIP) is a perylene-based aromatic hydrocarbon that exhibits besides its good film forming properties a very high hole mobility already in thin films and high thermal stability. In this work we present X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) measurements taken on thin DIP films (nominal thicknesses: 1-90 Å) on rutile TiO₂(110). Diindenoperylene was deposited onto the well-characterized TiO₂(110) substrate with a (1x1) reconstruction using strictly controlled evaporation conditions (evaporation rate: 3Å/min, substrate temperature 298K). The decrease of the FWHM of the C1s peak with increasing film thickness indicate a different intermolecular interaction in the monolayer regime. By analyzing the attenuation of the substrate XPS signal, we find evidence for a Stranski-Krastanov growth mode (layer plus islands) under these preparation conditions. This observation is corroborated by AFM measurements showing a distinctive island formation.