Dresden 2006 – scientific programme
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CPP: Chemische Physik und Polymerphysik
CPP 23: POSTER Functional Organic Thin Films
CPP 23.18: Poster
Thursday, March 30, 2006, 17:00–19:00, P2
60 nm to 40 µ m channel lengths poly(3-hexyl-thiophene) field effect transistors - Identifying the inner transistor — •J. Seekamp, A. Hoppe, T. Balster, T. Muck, and V. Wagner — School of Engineering and Science, International University Bremen, 28759 Bremen, Germany
Polymer based nanoscale field effect transistors with poly(3-hexyl-thiophene)(P3HT)as the organic semiconductor were characterised and compared to longer channel devices. Meaningful mobility values are esential for this comparison. Recent publications agree on applied models either not fitting sufficiently or demanding for physical insight hardly obtainable [1,2]. A slightly different approach to analyse bottom contact field effect transistors with interdigitated Ti/Au (3nm/20nm) gold electrodes, 50nm silicon oxide as the gate insulator, P3HT and channel lengths between 60nm and 40µ m is proposed here. Firstly, results were analysed using the "classical" gradual channel approximation[2]. Apparent mobilities[1] achieved this way varied between 0.2cm2/(Vs) for 40µ m channel length and 10−3cm2/(Vs) for 60nm channel length in linear regime for high Vgs. These mobilities vary with Vds and Vgs. To achieve more consistent values the measured data were corrected for a gate source and a bulk current modelled as voltage controlled current sources. Analysis of such corrected data resulted in mobilities of around 10−3cm2/(Vs) for channel lengths between 20µ m and 125nm. Apparent short channel effects were only observed for shorter channel lengths which are comparable to the oxide thickness.[1]G.Wang,et al.,J.Appl.Phys. 93(10)(2003)6137;[2]M.L.Chabinyc,et al.,J.Appl.Phys.96(4)(2004)2063