Dresden 2006 – scientific programme
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HL: Halbleiterphysik
HL 50: Poster II
HL 50.46: Poster
Thursday, March 30, 2006, 16:30–19:00, P3
Topographical and electrical characterization of pentacene thin-film transistors using thiol-modified electrodes — •D.V. Pham1, C. Bock1, U. Kunze1, D. Käfer2, G. Witte2, and Ch. Wöll2 — 1Lehrstuhl für Werkstoffe und und Nanoelektronik, Ruhr-Universität Bochum, D-44780 — 2Lehrstuhl für Physikalische Chemie I, Ruhr-Universität Bochum, D-44780
We study the influence of thiol monolayers on the topography as well as on the electrical characteristics of pentacene thin film transistors. The electrodes are modified by dodecanethiol, heptanethiol and anthracenethiol, respectively. A sample with untreated Ti/Au (1 nm/25 nm) electrodes acts as reference sample. The roughness analysis of the films emphasizes the preferential growth of pentacene on the untreated gold layer. The best morphology of the organic film is achieved with electrodes treated with dodecanethiol for a channel length of 500 nm. Since alcanethiols are isolators, the injection of the charge carriers from the gold electrode into the active region is strongly reduced. Nevertheless the performance of pretreated OFETs is superior compared to the reference sample. The best results are obtained with anthracenethiol treatment. The morphology of the film is homogeneous and, due to its semiconducting behaviour, high drain currents are possible. The threshold voltage of this sample is 2 V and the ON/OFF ratio amounts to 106.