Regensburg 2007 – scientific programme

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DS: Fachverband Dünne Schichten

DS 1: Organic Thin Films I

DS 1.2: Talk

Monday, March 26, 2007, 09:45–10:00, H32

Influence of substrate treatment and temperature on the electronic structure of diindenoperylene (DIP) thin films on Ag(111) — •Stefan Krause, Sönke Sachs, Achim Schöll, and Eberhard Umbach — University of Würzburg, Experimental Physics II, Am Hubland, 97074 Würzburg, Germany

Diindenoperylene (DIP) has recently attracted high interest in the organic electronics community due to the reported very high hole mobilitiy and favorable ordering properties in thin films on SiO₂ and gold substrates.

In this work we focus on the growth of DIP on the stronger interacting Ag(111) substrate. Due to the increased interface interaction an additional influence of the substrate can be expected, giving additional possibilities to manipulate the film growth. Ultraviolet Photoelectron Spectroscopy (UPS) data show substantial differences in the valence electronic structure before and after the annealing of low temperature deposited films. The annealing is believed to increase the degree of structural order particularly in the case of film growth far from thermal equilibrium conditions. Moreover, a marked influence of the substrate treatment could also be observed in the UPS spectra. The Ag(111) sample reveals a change of the work function depending on the duration and temperature of the annealing cycle after the Ar⁺-sputter treatment which can be associated with differences in the step density. The photoemission results indicate that different structural phases with different intermolecular interaction exist on the substrate morphology and growth parameters.