Impact of semiconductor/metal interfaces on contact resistance and operating speed of organic thin film transistors

Wudyalew T. Wondmagegn, Nikhil T. Satyala, Ron J. Pieper, Manuel Angel Quevedo Quevedo-López, Srinivas Gowrisanker, Husam N. Alshareef, Harvey J. Stiegler, Bruce E. Gnade

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


The contact resistance of field effect transistors based on pentacene and parylene has been investigated by experimental and numerical analysis. The device simulation was performed using finite element two-dimensional drift-diffusion simulation taking into account field-dependent mobility, interface/bulk trap states and fixed charge density at the organic/insulator interface. The width-normalized contact resistance extracted from simulation which included an interface dipole layer between the gold source/drain electrodes and pentacene was 91 kΩcm. However, contact resistance extracted from the simulation, without consideration of interface dipole was 52.4 kΩcm, which is about half of the experimentally extracted 108 kΩcm. This indicates that interface dipoles are critical effects which degrade performances of organic field effect transistors by increasing the contact resistance. Using numerical calculations and circuit simulations, we have predicted a 1 MHz switching frequency for a 1 μm channel length transistor without dipole interface between gold and pentacene. The transistor with dipole interface is predicted, via the same methods, to exhibit an operating frequency of less than 0.5 MHz. © 2010 Springer Science+Business Media LLC.
Original languageEnglish (US)
Pages (from-to)144-153
Number of pages10
JournalJournal of Computational Electronics
Issue number1-2
StatePublished - Sep 24 2010

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: We gratefully acknowledge the Department of Defense for supporting this work (Army Research Office Contract W911NF-07-2-0059).

ASJC Scopus subject areas

  • Modeling and Simulation
  • Atomic and Molecular Physics, and Optics
  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering


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