Interface properties of OFETs based on an air-stable n-channel perylene tetracarboxylic diimide semiconductor

Franziska Lüttich, Daniel Lehmann*, Marion Friedrich, Zhihua Chen, Antonio Facchetti, Christian Von Borczyskowski, Dietrich R.T. Zahn, Harald Graaf

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

In this study, several experimental techniques were employed to gain insights into the molecular interactions at the interfaces in organic field-effect transistors (OFETs). A self-assembled monolayer (SAM) was applied to the gate insulator to influence the interactions at the interface. Macroscopic electrical measurements, microscopic potentiometry, absorption/luminescence spectroscopy, and ellipsometry are combined to study top-contact OFETs based on an air-stable n-channel perylene derivative. They show clearly the advantage and capability of local electrical investigations compared to DC electrical characterization. The DC electrical measurements provide an improvement of the electron mobilities within the channel and unchanged contact resistances (within the error bars). Only the potentiometry allowed a deeper insight: It reveals a small decrease of the source contact resistance and a drain bias dependence of the mobility, which decreases due to prior hydrophobization of the SiO 2 gate insulator. This is attributed to different charge carrier trap concentrations and injection barriers in the organic semiconductor near the dielectric interface caused by diffused water which is discussed in detail. The optical absorption/luminescence spectroscopy and ellipsometry indicate an unchanged ordered molecular arrangement with a molecular tilt angle of (33±4)° with respect to the dielectric surface and rather weak intermolecular interaction for the devices with treated and untreated SiO 2.

Original languageEnglish (US)
Pages (from-to)585-593
Number of pages9
JournalPhysica Status Solidi (A) Applications and Materials Science
Volume209
Issue number3
DOIs
StatePublished - Mar 2012

Keywords

  • Kelvin probe force microscopy
  • field-effect transistors
  • optical constants
  • organic semiconductors

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Electrical and Electronic Engineering
  • Materials Chemistry

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