Regensburg 2010 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 16: Organic, polymeric, biomolecular films - also with adsorbates

O 16.1: Vortrag

Montag, 22. März 2010, 15:00–15:15, H46

Initial growth of crystalline rubrene thin film growth on mica (001) — •Harald Zaglmayr¹, Lidong Sun¹, Günther Weidlinger¹, Shaima'a Abd Al-Baqi², Dmitrii Nabok³, Peter Zeppenfeld¹, Helmut Sitter², and Claudia Ambrosch-Draxl³ — ¹Institute of Experimental Physics, Johannes Kepler University Linz, Altenbergerstraße 69, A-4040 Linz, Austria — ²Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenbergerstraße 69, A-4040 Linz, Austria — ³Department of Material Physics, Montanuniversity Leoben, Franz-Josef-Straße 18, A-8700 Leoben, Austria

Epi-fluorescence and laser scanning confocal microscopy (LSCM) have been used to investigate the morphology and optical properties of rubrene thin films at the early stage of crystallization and rubrene single crystals with a diameter of several tens of micrometers. The films were prepared on a muscovite mica substrate by hot wall epitaxy. The initial growth proceeds via the formation of a wetting layer and the nucleation of islands with an amorphous structure. Crystallization starts when the amorphous islands coalesce and needle like crystalline fibers are formed in the gap between the islands. The crystalline fibers then grow on top and in between the original amorphous islands leading to an "open network" of islands. The latter acts as a basis for the growth of semi-crystalline spherulites. For the rubrene single crystals, the spatially resolved photoluminescence spectrum shows a strong dependence on the orientation, which can be attibuted to the optical anisotropy of the crystals.