Regensburg 2013 – scientific programme

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DS: Fachverband Dünne Schichten

DS 32: Poster Session IV: Atomic layer deposition; Organic thin films; Organic Electronics and Phototovoltaics; Organic Materials for Spintronics - from spinterface to devices; Thin film photovoltaic materials and solar cells

DS 32.12: Poster

Thursday, March 14, 2013, 17:00–20:00, Poster B2

Initial growth of ultra-thin films of pentacene on mica: Influence of water and substrate morphology — •Levent Tümbek, Roman Lassnig, and Adolf Winkler — Institute of Solid State Physics, Graz University of Technology, Austria

In recent years organic electronic devices (OFETs, OLEDs) became a highly active topic in surface science due to their novel properties. A full understanding and control of the formation of organic films is a requirement for improving existing devices and further innovation. This study describes the behavior of pentacene film growth on the model substrate mica under well controlled UHV conditions. Physical vapor deposition (PVD) was the method of choice to prepare films from sub- monolayers up to multilayers and a quartz micro balance was applied to determine the pentacene film thickness. Argon ion sputtering was used for modifying the surface morphology. For the characterization of the film and substrate XPS, AES, TDS and ex-situ AFM was applied. It can be shown by AFM that sputtering changed the film morphology from needle-like islands, composed of lying molecules, to dendritic islands, composed of standing molecules. In the former case a wetting layer could be identified by TDS. Furthermore, it can be demonstrated that pentacene film formation depends strongly on the partial pressure of water vapor present during deposition. Regarding the adsorption kinetics, TDS revealed that the initial sticking coefficient of pentacene on mica is smaller than unity.