Dresden 2006 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 23: POSTER Functional Organic Thin Films

CPP 23.23: Poster

Donnerstag, 30. März 2006, 17:00–19:00, P2

Influence of source/drain contact metal on organic field-effect transistors and MIS- capacitors — •Andrei Herasimovich, Ingo Hoerselmann, and Susanne Scheinert — TU Ilmenau, PF, 98684 Ilmenau, Germany

We have investigated the influence of the contact material on the current characteristics of organic field-effect transistors (OFETs) and on the frequency response of MIS-capacitors, based on spin coated poly(3-hexylthiophene) (P3HT). Aluminium contacts were evaporated on one half of the substrate and gold contacts on the other one. The measured frequency response of the capacitance shows clearly a smaller cut-off frequency in the case of the Al contact. The measured output characteristics of the transistor with gold source/drain contacts show a linear dependence at small drain voltages whereas the increase of the current for Al contacts is non-linear. Such non-linearity was attributed in [1] to the field dependence of the mobility due to the Poole-Frenkel effect, whereas in [2] series resistances are described as the reason. Using different materials for the contacts, we can investigate these effects separately. We discuss the temperature influence on the non-linearities in the characteristics of the OFETs and on the impedance of the MOS- capacitors and compare the obtained results with these ones obtained from 2D simulations to clarify the reasons for the measured peculiarities.

[1] P. Stallinga et al., Appl. Phys. Lett. 96, 5277 (2004)

[2] G. Horowitz et al., J. Appl. Phys. 87, 4456 (2000)