Article All About the Interface: Do Residual Contaminants at A High‐Quality h‐BN Monolayer Perylene Diimide Interface Cause Charge Trapping?

Lukas Renn ; Lisa S. Walter ; Kenji Watanabe SAMURAI ORCID (National Institute for Materials Science) ; Takashi Taniguchi SAMURAI ORCID (National Institute for Materials Science) ; R. Thomas Weitz

Adv Materials Inter - 2022 - Renn - All About the Interface Do Residual Contaminants at A High‐Quality h‐BN Monolayer.pdf
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Lukas Renn, Lisa S. Walter, Kenji Watanabe, Takashi Taniguchi, R. Thomas Weitz. All About the Interface: Do Residual Contaminants at A High‐Quality h‐BN Monolayer Perylene Diimide Interface Cause Charge Trapping?. Advanced Materials Interfaces. 2022, 9 (10), 2101701. https://doi.org/10.1002/admi.202101701
SAMURAI

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(abstract)

Intrinsic charge transport in molecularly thin organic semiconducting crystals is critically sensitive to the quality of the interfaces required to perform the electrical measurements. Most prominent are the dielectric-semiconductor and semiconductor-metal interface. While impacts from the latter on charge transport can be extracted by four-terminal measurements, the impact of the dielectric interface can only be minimized, typically by utilizing inert dielectrics. Here we show, that the charge transport in organic field-effect transistors based on the n-type small molecule PDI1MPCN2 can be improved up to one order of magnitude by using hexagonal boron nitride (h-BN) as dielectric, compared to a standard SiO2 substrate. Using temperature-dependent two- and four-point measurements, we systematically analyze the charge-transport properties of our devices, where we obtain high 4-terminal mobilities of up to 5.0 〖cm〗^2⁄Vs. The high mobility likely stems from decreased charge-carrier trapping at the semiconductor-dielectric interface due to the smooth and continuous surface of the inert h-BN. Nevertheless, the temperature dependencies of the mobility, threshold voltage and interface-state trap density suggest, that charge-carrier trapping at the dielectric-semiconductor interface still exists. By comparing our data to transport studies performed on thin air-gapped organic films, we conclude that an interfacial layer (most likely water or solvent residues) between h-BN and the monolayer PDI1MPCN2 causes charge trapping.

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Keyword: Charge transport, organic semiconducting crystals, hexagonal boron nitride

Date published: 2022-01-29

Publisher: Wiley

Journal:

  • Advanced Materials Interfaces (ISSN: 21967350) vol. 9 issue. 10 2101701

Funding:

  • Solar Technologies go Hybrid
  • Deutsche Forschungsgemeinschaft
  • Japan Society for the Promotion of Science 19H05790
  • Ministry of Education, Culture, Sports, Science and Technology JPMXP0112101001
  • Japan Society for the Promotion of Science JP20H00354

Manuscript type: Publisher's version (Version of record)

MDR DOI:

First published URL: https://doi.org/10.1002/admi.202101701

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Updated at: 2025-02-26 08:30:49 +0900

Published on MDR: 2025-02-26 08:30:50 +0900

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