Regensburg 2010 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 47: Topical Session Growth Kinetics III
MM 47.4: Talk
Thursday, March 25, 2010, 11:15–11:30, H4
Smoothening at the organic-organic heterostructure interface — •Alexander Hinderhofer1, Stefan Kowarik1,2, Alexander Gerlach1, Frank Schreiber1, and Federico Zontone3 — 1Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany — 2Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA — 3ESRF, 6 Rue Jules Horowitz, BP 220, 38043 Grenoble, France
In situ real-time x-ray reflectivity and complementary atomic force microscopy are used to monitor crystallinity and roughness evolution during growth of thermally evaporated organic heterostructures, using perfluoropentacene (PFP) on diindenoperylene (DIP) and pentacene (PEN) on PFP. Surface smoothening during evaporation of the second material on top of the first is observed for both systems. The smoothening mechanism can be rationalized by a lowered step edge barrier, as compared to homoepitaxy, i.e. the step edge barrier for certain molecules (PFP, PEN) is very low for diffusion on a molecular crystal of a different species (DIP, PFP). In addition, we find an exceptionally well-ordered interface for PEN-on-PFP growth and PEN growth with very low roughening. A heterostructure of these materials scatters x-rays coherently over the entire thickness.
Material combinations such as those presented here may be used as model cases for organic-organic interface engineering.