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Proceedings Paper

Polarization-induced transport in organic field-effect transistors: the role of ferroelectric dielectrics
Author(s): Suchismita Guha; Amrit Laudari
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Paper Abstract

The ferroelectric nature of polymer ferroelectrics such as poly(vinylidene fluoride) (PVDF) has been known for over 45 years. However, its role in interfacial transport in organic/polymeric field-effect transistors (FETs) is not that well understood. Dielectrics based on PVDF and its copolymers are a perfect test-bed for conducting transport studies where a systematic tuning of the dielectric constant with temperature may be achieved. The charge transport mechanism in an organic semiconductor often occurs at the intersection of band-like coherent motion and incoherent hopping through localized states. By choosing two small molecule organic semiconductors - pentacene and 6,13 bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene) – along with a copolymer of PVDF (PVDF-TrFe) as the dielectric layer, the transistor characteristics are monitored as a function of temperature. A negative coefficient of carrier mobility is observed in TIPS-pentacene upwards of 200 K with the ferroelectric dielectric. In contrast, TIPS-pentacene FETs show an activated transport with non-ferroelectric dielectrics. Pentacene FETs, on the other hand, show a weak temperature dependence of the charge carrier mobility in the ferroelectric phase of PVDF-TrFE, which is attributed to polarization fluctuation driven transport resulting from a coupling of the charge carriers to the surface phonons of the dielectric layer. Further, we show that there is a strong correlation between the nature of traps in the organic semiconductor and interfacial transport in organic FETs, especially in the presence of a ferroelectric dielectric.

Paper Details

Date Published: 25 August 2017
PDF: 17 pages
Proc. SPIE 10365, Organic Field-Effect Transistors XVI, 103650I (25 August 2017); doi: 10.1117/12.2273232
Show Author Affiliations
Suchismita Guha, Univ. of Missouri (United States)
Amrit Laudari, Univ. of Missouri (United States)

Published in SPIE Proceedings Vol. 10365:
Organic Field-Effect Transistors XVI
Iain McCulloch; Oana D. Jurchescu, Editor(s)

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