Distinguishing Between Nonlinear Channel Transport and Contact Effects in Organic FETs

Published

August 30, 2007

Author(s)

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

Abstract

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

Pub Type

Conferences

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Keywords

charge transport in OFETs

Citation

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], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=32741 (Accessed April 25, 2024)