Berlin 2005 – wissenschaftliches Programm

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SYOO: Organic Optoelectronics and Photonics

SYOO 6: Poster

SYOO 6.41: Poster

Montag, 7. März 2005, 18:00–20:00, Poster TU A

Surface potential profiling on organic thin film transistors by photoemission-electron-microskopy (PEEM) — •Klaus Müller, Yevgen Burkov, and Dieter Schmeisser — Brandenburgische Technische Uni. Cottbus, Angewandte Physik-Sensorik, 03013 Cottbus, P.O.Box 101344, Germany

Surface potential imaging with Photoemission-electron-microskopy (PEEM) in high lateral resolution is introduced as a new tool for the characterisation of organic transistor structures. We use source-drain- electrode structures of different organic materials like carbon-black or graphite plotted on a printing foil. Semiconducting regioregular Poly(3-Hexylthiophene-2,5-diyl) (P3HT) was deposited by spin coating. For our measurements we used radiation of a standard high pressure Hg-lamp (4,9 eV) and synchrotron radiation at the BESSYII-U49/2 beam line. In contrast to Kelvin-AFM measurements of the surface potential, PEEM enables a simultaneous analysis of chemical composition by photoelectron spectroscopy. UPS, for example, at zero potential gives information on chemical homogeneity of the organic semiconductor in lateral resolution. PEEM images at applied voltages, compared with UPS-spectra, gives informations on doping profiles in the semiconductor, for example. In conclusion, PEEM should be a complementary method for characterisation of the surface potential with Kelvin-AFM. In addition, PEEM gives opportunities for measurements of chemical composition in the working state of the transistor (applied voltages).