Article

Ferroelectric tunnel junctions with graphene electrodes

  • Nature Communications 5, Article number: 5518 (2014)
  • doi:10.1038/ncomms6518
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Abstract

Polarization-driven resistive switching in ferroelectric tunnel junctions (FTJs)—structures composed of two electrodes separated by an ultrathin ferroelectric barrier—offers new physics and materials functionalities, as well as exciting opportunities for the next generation of non-volatile memories and logic devices. Performance of FTJs is highly sensitive to the electrical boundary conditions, which can be controlled by electrode material and/or interface engineering. Here, we demonstrate the use of graphene as electrodes in FTJs that allows control of interface properties for significant enhancement of device performance. Ferroelectric polarization stability and resistive switching are strongly affected by a molecular layer at the graphene/BaTiO3 interface. For the FTJ with the interfacial ammonia layer we find an enhanced tunnelling electroresistance (TER) effect of 6 × 105%. The obtained results demonstrate a new approach based on using graphene electrodes for interface-facilitated polarization stability and enhancement of the TER effect, which can be exploited in the FTJ-based devices.

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Acknowledgements

This research was supported by the US Department of Energy, Office of Science, Basic Energy Sciences, Division of Materials Sciences and Engineering, under Award DE-SC0004876 (electrical characterization and fabrication of thin films), and by the National Science Foundation through Materials Research Science and Engineering Center under Grant No. DMR-0820521 (theoretical modelling), EPSCoR under Award No. EPS-1004094 (graphene patch fabrication and spectroscopy) and DMREF Grant No. DMR-1234096 (interfacial design of bottom electrodes).

Author information

Author notes

    • H. Lu
    •  & A. Lipatov

    These authors contributed equally to this work

Affiliations

  1. Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588, USA

    • H. Lu
    • , D. J. Kim
    • , M. Y. Zhuravlev
    • , E. Y. Tsymbal
    •  & A. Gruverman
  2. Department of Chemistry, University of Lincoln, Nebraska 68588, USA

    • A. Lipatov
    •  & A. Sinitskii
  3. Department of Materials Science and Engineering, University of Wisconsin, Madison, Wisconsin 53706, USA

    • S. Ryu
    • , H. Lee
    •  & C. B. Eom
  4. Kurnakov Institute for General and Inorganic Chemistry, RAS, 119991 Moscow, Russia

    • M. Y. Zhuravlev
  5. Faculty of Liberal Arts and Sciences, St Petersburg State University, 190000 St Petersburg, Russia

    • M. Y. Zhuravlev
  6. Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, Nebraska 68588, USA

    • E. Y. Tsymbal
    • , A. Sinitskii
    •  & A. Gruverman

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Contributions

A.G., A.S. and E.Y.T. conceived the idea, designed the experiment and wrote the paper. H. Lu and D.J.K. implemented experimental measurements. A.L. and A.S. performed fabrication and spectroscopic characterization of the graphene electrodes for tunnel junctions. S.R., H. Lee and C.B.E. fabricated the ferroelectric films. M.Y.Z. and E.Y.T. performed the modelling of the electroresistance effect. All the authors contributed to the final manuscript review.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to A. Gruverman.

Supplementary information

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    Supplementary Information

    Supplementary Figures 1-10, Supplementary Notes 1-6 and Supplementary References.

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