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Distinguishing Between Nonlinear Channel Transport and Contact Effects in Organic FETs



Behrang Hamadani, Jeremy LeBoeuf, R J. Kline, Iain McCulloch, Martin Heeney, Curt A. Richter, Lee J. Richter, David J. Gundlach


We investigate charge injection and transport in organic field-effect transistors fabricated by using poly(2,5-bis(3-tetradecylthiophene-2-yl)thieno[3,2-b]thiophene) (pBTTT-C14) as the active polymer layer. We show that in high mobility devices where the channel resistances are low compared to the contact resistances, the device performance can be dominated by the metal/organic semiconductor (OSC) contacts. However, in sets of devices where the channel resistance is dominant over the contacts (usually the lower mobility devices), we see pronounced field dependence in the saturation regime mobilities consistent with a Poole-Frenkel model of charge transport. We compare these results with a different set of devices fabricated with poly(3-hexylthiophene) (P3HT) as the active layer, showing low contact resistances and similar Poole-Frenkel mobility behavior observed in the pBTTT devices. The field-dependent mobility in short-channel devices produces nonlinear output current-voltage characteristics which can be modeled consistently in the Poole-Frenkel framework
Proceedings Title
Proceedings of SPIE
Conference Dates
August 26-30, 2007
Conference Location
San Diego, CA, USA
Conference Title
SPIE - The International Society for Optical Engineering


charge transport in OFETs


Hamadani, B. , LeBoeuf, J. , Kline, R. , McCulloch, I. , Heeney, M. , Richter, C. , Richter, L. and Gundlach, D. (2007), Distinguishing Between Nonlinear Channel Transport and Contact Effects in Organic FETs, Proceedings of SPIE, San Diego, CA, USA, [online], (Accessed May 25, 2024)


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Created August 29, 2007, Updated October 12, 2021