Berlin 2015 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 12: Organic Thin Films
CPP 12.5: Talk
Monday, March 16, 2015, 16:15–16:30, H 2032
Shape anisotropy of organic thin films induced by ion-beam irradiated rippled substrates — •Markus Kratzer1, Dominik Wrana2, Konrad Szajna2, Franciszek Krok2, and Christian Teichert1 — 1Institute of Physics, Montanuniversitaet Leoben, Franz Josef Straße 18, 8700 Leoben, AUSTRIA — 2Institute of Physics, Jagiellonian University, Lojasiewicza 11, 30-348 Krakow, POLAND
Control over thin film growth morphologies of conjugated molecules is a key issue in organic electronics. Here, we investigated the growth of the organic semiconductor para-hexaphenyl (6P) on ion bombarded, rippled TiO2(110) surfaces. Such substrates are highly anisotropic, representing one-dimensionally patterned templates with alternating ascending and descending step trains exhibiting typical step distances smaller 1 nm. 6P islands have been observed featuring clear shape anisotropy and discrete island widths according to the ripple wavelength. These observations are addressed to anisotropic detachment of molecules differently bound to the island rim at ascending and descending steps. A change of the average ripple length from ~11 nm to ~60 nm, resulted in a change of the average islands’ length-to-width ratio from ~1.5:1 and ~4.5:1. In addition, strong diffusion anisotropy along and perpendicular to the ripples was found to be responsible for an increasing island density with decreasing ripple length.