Due to their potential in electronic and optoelectronic applications, semiconducting organic materials are the focus of a rapidly increasing research activity. Organic field-effect transistors, organic light-emitting diodes, or organic solar cells are only a few examples of tailored organic device structures. [1] Besides high charge-carrier mobilities in the organic layer, the proper function of the contact between the metal and the organic layer is of great importance for the device performance. Thus, knowledge of the associated morphology of the metal± organic interface as well as its thermal stability is essential. Hitherto, only a few studies of metal±organic interfaces exist, mostly on disordered polymers used as low dielectric constant material in conventional microelectronic fabrication processes [2] and some on Langmuir±Blodgett films and on ultrahigh vacuum (UHV)-deposited organic thin films. In this paper, we present a study of the interface between gold and diindenoperylene thin films (DIP, C 32 H 16 , Fig. ) as a model system for metal contacts on organic electronic devices. We examine the necessary preparation conditions that lead to a well-defined gold/DIP interface in the as-grown state by cross-sectional TEM and study the thermal stability of the DIP thin film at elevated temperatures by in-situ X-ray-scattering. Finally, we investigate the thermal stability of the met-al±organic interface employing in-situ, high-resolution Rutherford backscattering spectrometry (RBS) as a function of temperature. The annealing studies are particularly important to address the issue of thermal stability of devices operating at elevated temperatures.
DIP was chosen as the organic material, since the surface of the DIP films exhibits large terraces (up to 7000 ) with monomolecular steps of 16.5 . Thus, DIP films are very well defined and ideally suited for the study of the interfacial structure of metal contacts on organic thin films. Moreover, DIP exhibits excellent crystalline order and very good chargetransport properties associated with it. [5] Gold is widely used for contacting organic electronic devices and rather inert, hence, specific chemical interactions play only a minor role. This allows us to focus on the role of substrate temperature ±