Measuring the Barrier Height at Transition Metal Dichalcogenide Heterojunctions

POSTER

Abstract

Transition metal dichalcogenides (TMDs) have attracted much interest in recent years as channel materials for high performance Field Effect Transistors (FETs). However, a large Schottky barrier tends to form at the interface of TMD channels and most conventionally used metal contacts. Chuang et al. demonstrated low-resistance Ohmic contacts to WSe2, MoS2, and MoSe2 channels by inserting a degenerately doped TMD at the contact areas.1 While the low contact resistance suggests a substantially reduced barrier, a systematic study is necessary to probe the reduction of the Schottky Barrier Height (SBH) and better understand the mechanism of carrier injection at TMD heterojunctions that enables the success of the 2D-2D contact strategy. In this work, we investigate how the band alignment affects the Schottky barrier Height.
While ohmic contacts are achieved between degenerately -doped MoS2 drain/source and WSe2 channel, a SBH in the range of tens to hundreds of meV is observed for individual 2D/2D junctions consisting of -doped WSe2 contact and MoSe2 channel. For comparison, we also study isolated Schottky barriers at TMD/metal junctions by fabricating asymmetrically contacted WSe2 FETs consisting of a 2D/2D ohmic contact and a TMD/metal Schottky contact.

Presenters

  • Upendra Rijal

    • Physics and Astronomy, Wayne State Univ
    • Physics and Astronomy, Wayne State University

Authors

  • Upendra Rijal

    • Physics and Astronomy, Wayne State Univ
    • Physics and Astronomy, Wayne State University

  • Arthur Bowman

    • Physics and Astronomy, Wayne State Univ
    • Physics and Astronomy, Wayne State University

  • Kraig Andrews

    • Physics and Astronomy, Wayne State Univ

  • Michael Koehler

    • Department of Materials Science and Engineering, The University of Tennessee
    • Materials Science and Engineering, The University of Tennessee
    • Department of Materials Science and Engineering, University of Tennessee

  • David Mandrus

    • Department of Materials Science and Engineering, The University of Tennessee
    • Oak Ridge National Lab
    • Oak Ridge National Laboratory
    • Department of Materials Science and Engineering, University of Tennessee
    • University of Tennessee
    • Materials Science and Technology, Oak Ridge National Laboratory
    • Materials Science and Engineering, The University of Tennessee
    • Materials Science and Engineering, University of Tennessee
    • Material Science and Technology Division, Oak Ridge National Laboratory
    • Oakridge National Laboratory
    • University of Tennessee, Knoxville
    • Univ of Tennessee, Knoxville

  • Zhixian Zhou

    • Physics and Astronomy, Wayne State Univ
    • Physics and Astronomy, Wayne State University