Regensburg 2004 – wissenschaftliches Programm

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SYOH: Organic and Hybrid Systems for Future Electronics

SYOH 5: Poster

SYOH 5.66: Poster

Donnerstag, 11. März 2004, 18:00–21:00, B

Transparent organic field effect transistors based on rf magnetron sputtered alumina films — •Michael Voigt and Moritz Sokolowski — Institut für Physikalische und Theoretische Chemie, Universität Bonn, Wegelerstrasse 12, 53115 Bonn

Organic field effect transistors (OFETs) were fabricated by evaporation of pentacene (Pc) onto alumina insulator films (d = 160–320 nm). The alumina films were prepared on ITO covered glass (gate–electrode) by rf magnetron sputtering and show under optimized sputter conditions breakdown fields of 1.2 MV/cm and a dielectric constant of ∼7. AFM investigations reveal that their surface is rather rough (rms = 3.6 nm). Source and drain contacts (Au; d = 50 nm) were prepared by shadow mask technique either on top of the Pc films or on top of the alumina. The channel length L was 50 µm. In the first case, a charge mobility of 0.01 cm²/Vs was observed, a value of the same order as we obtained for comparable OFETs on SiO₂. In the second case, no field effect mobility was observed, which we relate to a detrimental influence of Au clusters on the alumina surface on the Pc film formation. Since the OFET–channel is transparent, we can control growth of the Pc films by polarization microscopy. Supported through the DFG-priority program No-dqOrganic field effect transistorsNo-dq.