Non-Thermionic Switching in an Atomically Thin WSe<sub>2</sub> Transistor with the Phase-Change Material VO<sub>2 </sub>Contact

ORAL

Abstract

By using the metal-insulator transition material VO2 (TC ~ 340 K) as a contact electrode, we demonstrate an atomically thin WSe2 transistor whose subthreshold swing (SS) is limited not by the Boltzmann limit but by the abruptness of the phase transition of VO2. Polycrystalline VO2 films wtith thicknesses of 50 nm were grown on Al2O3 by the pulsed layer deposition method and etched to 1 μm in width. Few-layer WSe2 was transferred onto the VO2 wire so that the VO2 served as one of the contact electrodes. After defining another electrode with Ti/Au, a gate dielectric of hBN was transferred. The transistor is on the off-state, with the VO2 electrode being in the insulating phase at room temperature. However, the drain current shows abrupt increase at a given gate voltage, suggesting that the pahse transition in VO2 is induced by Joule heating. We observe a relatively small value of 150 mV/dec. for the SS, but this is still larger than the thermal limit of 60 mV/dec. We expect that the SS could be further improved by employing single crystalline VO2 that shows an abrupt transition.

*Supported by JSPS KAKENHI (17K14658), Yazaki Memorial Foundation for Science and Technology, and the Research Program of "Five-star Alliance" in "NJRC Mater. & Dev.

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Presenters

  • Mahito Yamamoto

    • ISIR, Osaka Univ.

Authors

  • Mahito Yamamoto

    • ISIR, Osaka Univ.

  • Teruo Kanki

    • ISIR, Osaka Univ.

  • Azusa Hattori

    • ISIR, Osaka Univ.

  • Ryo Nouchi

    • Department of Physics and Electronics, Osaka Prefecture Univ.

  • Kenji Watanabe

    • National Institute for Materials Science
    • NIMS
    • National Institute for Material Science
    • Advanced Materials Laboratory, National Institute for Materials Science
    • National Institute of Materials Science
    • Research Center for Functional Materials, National Institute for Materials Science
    • National Institute for Materials Science (NIMS
    • Advanced Materials Laboratory, NIMS
    • National Institute for Materials Science, Advanced Materials Laboratory
    • National Institue for Materials Science
    • National Institute of Material Science
    • National Institute for Matericals Science
    • Advanced Materials Laboratory
    • National Institute for Materials Science, 1-1 Namiki
    • Advanced materials laboratory, National institute for Materials Science
    • NIMS-Japan

  • Takashi Taniguchi

    • National Institute for Materials Science
    • NIMS
    • National Institute for Material Science
    • Advanced Materials Laboratory, National Institute for Materials Science
    • National Institute of Materials Science
    • Research Center for Functional Materials, National Institute for Materials Science
    • National Institute for Materials Science (NIMS
    • Advanced Materials Laboratory, NIMS
    • National Institute for Materials Science, Advanced Materials Laboratory
    • National Institue for Materials Science
    • National Institute of Material Science
    • National Institute for Matericals Science
    • Advanced Materials Laboratory
    • National Institute for Materials Science, 1-1 Namiki
    • NIMS-Japan

  • Keiji Ueno

    • Department of Chemistry, Saitama Univ.
    • Saitama University

  • Hidekazu Tanaka

    • ISIR, Osaka Univ.