| AVS 54th International Symposium | |
| Thin Film | Wednesday Sessions |
| Session TF-WeA |
| Session: | Oblique Angle Deposition |
| Presenter: | C. Teichert, University of Leoben, Austria |
| Authors: | C. Teichert, University of Leoben, Austria G. Hlawacek, University of Leoben, Austria P. Frank, Graz University of Technology, Austria A. Winkler, Graz University of Technology, Austria |
| Correspondent: | Click to Email |
Organic Semiconductors start to enter the market of consumer products as light emitting diodes, solar cells and thin film transistors. For the growth of reliable high quality devices a profound understanding of the processes related to formation of organic thin films is necessary. Here, we present an AFM study on the growth of para-sexiphenyl on a sputtered mica(001) surface. Para-sexiphenyl is a member of the group of small conjugated molecules with a high mobility1 and the ability to emit blue light.2 The morphology is characterized by the formation of mounds formed by upright standing molecules. Needle growth competes with the formation of the mounds. However, the characteristic layer distribution of the mounds can be fitted by a Poisson distribution. This shape is related to the Zeno effect known from inorganic epitaxy.3 The mound shape for different film thicknesses has been analysed. Furthermore, statistical roughness parameters such as rms roughness σ, hurst parameter α and mound separation λ have been evaluated. Growth exponent β and dynamic exponent 1/z can be calculated and agree with the predictions made by the Zeno model. The mound separation λ and the size of the top terrace allow estimating the size of the Ehrlich Schwoebel barrier responsible for the cross-sectional shape of the mounds. Work has been supported by Austrian Science Fund (FWF) National Research Network "Interface controlled and Functionalised Organic Films" (S9707-N08).
1 T. Birendra Singh, G. Hernandez-Sosa, H. Neugebauer, A. Andreev, H. Sitter, N.S. Sariciftci, Phys. Status Solidi B, 243, (2006) 3329.
2 A. Kadashchuk, A. Andreev, H. Sitter, N.S. Sariciftci, Y. Skryshevski, Y. Piryatinski, I. Blonsky, D. Meissner, Adv. Funct. Mater. 14 (2004) 970.
3 T. Michely and J. Krug; Islands, Mounds and Atoms (Springer, Berlin 2004).