Regensburg 2002 – wissenschaftliches Programm

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SYOH: Organische Halbleiter

SYOH 7: Poster

SYOH 7.23: Poster

Montag, 11. März 2002, 18:00–21:00, C

Characterization of the interfaces of the organic semiconductors CuPC and CuPCF₄ on Au, GeS(100) and ITO — •Heiko Peisert, Martin Knupfer, Torsten Schwieger, and Jörg Fink — Institute for Solid State Research, IFW Dresden, P.O. Box 270016, D-01171 Dresden, Germany

We present a study of the interface properties at the earliest stages of the deposition of the molecular organic semiconductor copper phthalocyanine (CuPC) and its fluorinated relative copper tetraflourophthalocyanine (CuPCF₄) on single crystalline Au(100) as well as on polycrystalline Au using photoemission spectroscopy. Despite the different orientation of the molecules on the two substrates, the observed energy level alignment is identical. Strong energetic shifts for coverages less than 1.5 nm are discussed in terms of both the formation bulk properties and the presence of image charges. We observe the formation of interface dipoles of 1.2 eV and 0.8 eV for CuPC and CuPCF₄, respectively, while band bending is very small.

Complementary investigations are carried out on the non-polar GeS(001) surface and on sputter-cleaned indium-tin-oxide (ITO). The systems CuPC/GeS(001) and CuPC/Au are compared to pin down photoemission final state effect contributions to the observed energy level shifts for ultra thin organic films. Whereas no strong interactions are observed on Au and GeS(001), it is shown that a chemical reaction occurs between the PC molecules and ITO which indicates the presence of interface states at these technically relevant interfaces.