Dielectric surface-controlled low-voltage organic transistors via n-alkyl phosphonic acid self-assembled monolayers on high-k metal oxide

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Author(s)

  • Orb Acton
  • Guy G. Ting
  • Patrick J. Shamberger
  • Fumio S. Ohuchi
  • Hong Ma

Detail(s)

Original languageEnglish
Pages (from-to)511-520
Journal / PublicationACS Applied Materials and Interfaces
Volume2
Issue number2
Publication statusPublished - 24 Feb 2010
Externally publishedYes

Abstract

In this paper, we report on n-alkyl phosphonic acid (PA) self-assembled monolayer (SAM)/hafnium oxide (HfO 2) hybrid dielectrics utilizing the advantages of SAMs for control over the dielectric/semiconductor interface with those of high-k metal oxides for low-voltage organic thin film transistors (OTFTs). By systematically varying the number of carbon atoms of the n-alkyl PA SAM from six to eighteen on HfO 2 with stable and low leakage current density, we observe how the structural nature of the SAM affects the thin-film crystal structure and morphology, and subsequent device performance of low-voltage pentacene based OTFTs. We find that two primary structural factors of the SAM play a critical role in optimizing the device electrical characteristics, namely, the order/ disorder of the SAM and its physical thickness. High saturation-field-effect mobilities result at a balance between disordered SAMs to promote large pentacene grains and thick SAMs to aid in physically buffering the charge carriers in pentacene from the adverse effects of the underlying high-k oxide. Employing the appropriate n-alkyl PA SAM/HfO 2 hybrid dielectrics, pentacene-based OTFTs operate under -2.0 V with low hysteresis, on-off current ratios above 1 × 10 6, threshold voltages below -0.6 V, subthreshold slopes as low as 100 mV dec-1, and field-effect mobilities as high as 1.8 cm2 V -1 s -1. © 2010 American Chemical Society.

Research Area(s)

  • Hybrid materials, Organic field-effect transistor, Organic semiconductor, Self-assembled monolayer

Citation Format(s)

Dielectric surface-controlled low-voltage organic transistors via n-alkyl phosphonic acid self-assembled monolayers on high-k metal oxide. / Acton, Orb; Ting, Guy G.; Shamberger, Patrick J. et al.
In: ACS Applied Materials and Interfaces, Vol. 2, No. 2, 24.02.2010, p. 511-520.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review