title: Broadening of Distribution of Trap States in PbS Quantum Dot Field-Effect Transistors with High-k Dielectrics.
abstract: We perform a quantitative analysis of the trap density of states (trap DOS) in PbS quantum dot field-effect transistors (QD-FETs), which utilize several polymer gate insulators with a wide range of dielectric constants. With increasing gate dielectric constant, we observe increasing trap DOS close to the lowest unoccupied molecular orbital (LUMO) of the QDs. In addition, this increase is also consistently followed by broadening of the trap DOS. We rationalize that the increase and broadening of the spectral trap distribution originate from dipolar disorder as well as polaronic interactions, which are appearing at strong dielectric polarization. Interestingly, the increased polaron-induced traps do not show any negative effect on the charge carrier mobility in our QD devices at the highest applied gate voltage, giving the possibility to fabricate efficient low-voltage QD devices without suppressing carrier transport.
authors.affiliation: Zernike Institute for Advanced Materials, University of Groningen , Nijenborgh 4, Groningen 9747AG, The Netherlands.|Department of Advanced Materials Science, School of Frontier Sciences, University of Tokyo , 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561, Japan.
authors.forename: Mohamad I
authors.initials: MI
authors.lastname: Nugraha
authors.affiliation: Department of Advanced Materials Science, School of Frontier Sciences, University of Tokyo , 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561, Japan.
authors.forename: Roger
authors.initials: R
authors.lastname: Häusermann
authors.affiliation: Department of Advanced Materials Science, School of Frontier Sciences, University of Tokyo , 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561, Japan.|JST, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan.
authors.forename: Shun
authors.initials: S
authors.lastname: Watanabe
authors.affiliation: Research Center for Organic Electronics, Yamagata University , 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Matsui
authors.affiliation: Materials for Electronics and Energy Technology, Friedrich-Alexander-Universität Erlangen-Nürnberg , Martensstraße 7, 91058 Erlangen, Germany.|Energie Campus Nürnberg , Fürther Straße 250, 90429 Nürnberg, Germany.
authors.forename: Mykhailo
authors.initials: M
authors.lastname: Sytnyk
authors.affiliation: Materials for Electronics and Energy Technology, Friedrich-Alexander-Universität Erlangen-Nürnberg , Martensstraße 7, 91058 Erlangen, Germany.|Energie Campus Nürnberg , Fürther Straße 250, 90429 Nürnberg, Germany.
authors.forename: Wolfgang
authors.identifier: http://orcid.org/0000-0003-0430-9550
authors.initials: W
authors.lastname: Heiss
authors.affiliation: Department of Advanced Materials Science, School of Frontier Sciences, University of Tokyo , 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Takeya
authors.affiliation: Zernike Institute for Advanced Materials, University of Groningen , Nijenborgh 4, Groningen 9747AG, The Netherlands.
authors.forename: Maria A
authors.identifier: http://orcid.org/0000-0001-9352-1902
authors.initials: MA
authors.lastname: Loi
keywords: PbS quantum dots; field-effect transistors; high-k; polaron; trap states