Mobility overestimation due to gated contacts in organic field-effect transistors

Published

March 10, 2016

Author(s)

Emily G. Bittle, David J. Gundlach, Oana Jurchescu, James I. Basham, Thomas Jackson

Abstract

Parameters used to describe the electrical properties of organic field-effect transistors, such as mobility and threshold voltage, are commonly extracted from measured current–voltage characteristics and interpreted by using the classical metal oxide–semiconductor field-effect transistor model. However, in recent reports of devices with ultra-high mobility (>40 cm2 V−1 s−1), the device characteristics deviate from this idealized model and show an abrupt turn-on in the drain current when measured as a function of gate voltage. In order to investigate this phenomenon, here we report on single crystal rubrene transistors intentionally fabricated to exhibit an abrupt turn-on. We disentangle the channel properties from the contact resistance by using impedance spectroscopy and show that the current in such devices is governed by a gate bias dependence of the contact resistance. As a result, extracted mobility values from d.c. current–voltage characterization are overestimated by one order of magnitude or more.

Citation

Nature Communication

Volume

7

Pub Type

Journals

Download Paper

https://doi.org/10.1038/NCOMMS10908

Citation

Bittle, E. , Gundlach, D. , Jurchescu, O. , Basham, J. and Jackson, T. (2016), Mobility overestimation due to gated contacts in organic field-effect transistors, Nature Communication, [online], https://doi.org/10.1038/NCOMMS10908 (Accessed October 10, 2025)