Berlin 2005 – wissenschaftliches Programm

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DS: Dünne Schichten

DS 23: Postersitzung I

DS 23.43: Poster

Freitag, 4. März 2005, 16:00–18:30, Poster TU B

Growth of crystalline Rubrene films — •Daniel Käfer, Gregor Witte und Christof Wöll — Physikalische Chemie I, Ruhr-Universität Bochum, 44780 Bochum

Rubrene a commonly used dye has recently been demonstrated to also exhibit a remarkably high charge carrier mobility in single crystals [1] which favours its use for molecular electronics applications. However, the growth of crystalline thin films of rubrene has yet not been achieved. Here we report results of a growth study of rubrene films prepared by molecular beam deposition on gold and silicon oxide substrates. Whereas at room temperature rather amorphous films are obtained the size of rubrene crystallites increases with rising temperature but their size is found to be limited by competing dewetting, decreasing sticking coefficients, and finally the desorption of rubrene. An improved crystal growth is achieved by using a modified ’hot wall’-type deposition cell which allows operation under UHV-conditions but at much higher partial vapour pressure. The resulting crystalline films and large single crystallites were characterized by AFM and SEM.

[1] V.C. Sundar et al. Science 303, 1644 (2004)