Dresden 2009 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 3: Focus Session: Interactions of Molecules with Dielectric Surfaces

DF 3.1: Hauptvortrag

Montag, 23. März 2009, 14:30–15:00, WIL A317

Interaction of molecules with dielectric surfaces: From single molecular adsorption to functional devices — •Lukas M. Eng — TU Dresden, Institut für Angewandte Photophysik, 01062 Dresden

Heterojunctions formed between organic/biological molecules and dielectric/ferroelectric substrates (such as organic FETs [1]) gain rapidly in interest due to the possibility of inducing novel and tunable functionality on the atomic/molecular scale. We report here on high-resolution topographic and surface potential investigations of polar and non-polar organic molecules deposited onto ultrathin dielectric layers of just 1 monolayer in thickness. Dipole formation was measured for several types of molecules resulting in both donor and acceptor-like molecular behavior for different molecule-substrate interactions [2,3]. Our multi-scale modeling [4] of molecular ordering [5] revealed a strong dependence on local electric fields, leading to distinctly different molecular pattern formation for instance at step edges and defect sites [6]. As such a "defect", we purposely introduced ferroelectric thin films having a remnant but switchable surface charge, in order to investigate their applicability as functional gate electrodes in ferroelectric organic field effect transistors. Moreover, we use such ferroelectric templates as templates for the controlled molecular adsorption, as will be demonstrated for nanowires attached along domain walls. - Acknowledgement: DFG. [1] K. Haubner, pss A 205 (2008) 430. [2] P. Milde, NT 19 (2008) 305501-1. [3] U. Zerweck, NT 18 (2007) 084006. [4] S. Gemming, J. Comput.-Aided Mater. Des. 14(S1) (2008) 211. [5] S. Gemming, EPJ: Special Topics 149 (2007) 145. [6] C. Loppacher, NT 17 (2006) 1568.