Regensburg 2002 – wissenschaftliches Programm

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SYOH: Organische Halbleiter

SYOH I: HV I

SYOH I.1: Hauptvortrag

Montag, 11. März 2002, 09:30–10:10, H37

Growth and Ordering of Organic Molecules on Surfaces — •Eberhard Umbach — Experimentelle Physik II, Univ. Würzburg, D-97074 Würzburg

The optical and electronic properties of organic thin films strongly depend on the morphology and order of the films as well as on their interfaces to substrate and contacts. The growth mechanism and the result of film growth are also largely determined by the properties of the interface to the substrate and by the growth parameters. They actually depend in a subtle way on the material- and site-specific bonding situation at the interface, on the interplay between the anisotropic intermolecular and molecule-substrate forces, and on the dynamics of adsorption and diffusion. Surface sensitive techniques recently revealed a wealth of unexpected phenomena. These range from various 2-dimensional phase transitions over manipulation of molecular orientation and metastability in organic layers to the temperature- and deposition rate-dependent transition from Franck-van-der-Merwe to Stranski-Krastanov growth. Various examples using different molecules and substrates will be discussed on the basis of selected experimental results, and the question will be addressed under which conditions epitaxial growth with large domain sizes can be achieved.