Regensburg 2004 – wissenschaftliches Programm
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SYOH: Organic and Hybrid Systems for Future Electronics
SYOH 7: Molecular Systems and Applications
SYOH 7.1: Fachvortrag
Freitag, 12. März 2004, 11:15–11:35, H1
Geometric and electronic structure of sexiphenyl grown on metal, oxygen modified metal and oxide — •Michael Ramsey1, Georg Koller1, Jan Ivanco1, Barbara Winter1, Steve Berkibile1, Roland Resel2, and Christian Teichert3 — 1Experimental Physics, University of Graz, A-8010 Graz, Austria — 2Solid State Physics,TU-Graz,A-8010,Austria — 3Physics, University Leoben,A-8700 Leoben,Austria
For device relevant organic films the organic films crystal structure, molecular orientation, film morphology and electronic structure are of prime importance. It will be demonstrated that all these properties can be drastically affected by the exact nature of the substrate surface on which they are grown. Here the results of sexiphenyl (6P) growth on model substrates ranging from clean and oxygen modified single crystal metal surfaces through to clear conducting oxide surfaces will be discussed. For growth on Al(111) at room temperature the ordered monolayer that forms provides the basis for the highly crystalline, single phase, epitaxial thick 6P that results. Chemisorbed oxygen at the Al surfaces leads to the formation of 6P films of near vertically oriented molecules. In contrast oxygen in the Ni(110)-(2x1)O acts as a template for the formation of strings of azimuthally oriented molecules parallel to the substrate. On TiO2(110) no wetting layer can be formed and large needle like 6P crystallites form. The micrometer long needles are oriented exclusively perpendicular to the atomic rows of the surface while the molecules within them are parallel them.