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Proceedings Paper

New insights into contact resistance at organic semiconductor contacts (Conference Presentation)
Author(s): Peter Ho

Paper Abstract

Achieving ohmic contacts is key to maximizing the performance of the organic semiconductor in field-effect transistors. The same is true also for organic solar cells, and light-emitting diodes. Recently, by tuning the work function of hole collection layers, and electron collection layers, in fine steps across the Fermi-level pinning threshold of the model photoactive layers in solar cells, which are particularly sensitive to charge extraction contact resistance, we obtain direct evidence for a non-ohmic to ohmic transition associated with strong suppression of resistivity at the contact, when the electrode work function crosses a second threshold beyond the onset of Fermi-level pinning. Detailed current balance analysis reveals this transition to be a fundamental feature of charge transfer kinetics, relevant to both injection and collection, at disordered semiconductor interfaces. Similar considerations apply also to field-effect transistor contacts. Using an enhanced transmission-line model, we show that it is possible to separate out contact resistance from carrier mobility effects, including both their current density and carrier density dependences, from measured IV curves, enabling the characterization of the true carrier mobility in field-effect transistors.

Paper Details

Date Published: 10 September 2019
Proc. SPIE 11097, Organic and Hybrid Field-Effect Transistors XVIII, 1109705 (10 September 2019); doi: 10.1117/12.2531838
Show Author Affiliations
Peter Ho, National Univ. of Singapore (Singapore)

Published in SPIE Proceedings Vol. 11097:
Organic and Hybrid Field-Effect Transistors XVIII
Iain McCulloch; Oana D. Jurchescu, Editor(s)

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