Origin of the Structural Defects and Conclusions

This work was supported by the Deutsche Forschungsgemeinschaft through the priority program Organic field effect transistors (SPP1121). We thank 

Kldter (Universitat Bonn) for support with the AFM measurements on the Pc films and M. Bohmer for the support in programming the automatic data collection. 

Horowitz, in Organic Electronics, edited by H. Klauk (Wiley-VCH, Weinheim, 2006). 

Krischner and B. Koppelhuber-Bitschnau, Rontgenstrukturanalyse und Rietveldmethode (Vieweg, Braun-schweigAViesbaden, 1994). 

Helmersson, and J.-E. Sundgren, Appl. Phys. Lett. 74, 200 

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