MISC

2019年10月9日

Barrier Formation at the Contacts of Vanadium Dioxide and Transition-Metal Dichalcogenides

ACS Applied Materials and Interfaces
  • Mahito Yamamoto
  • ,
  • Ryo Nouchi
  • ,
  • Teruo Kanki
  • ,
  • Shu Nakaharai
  • ,
  • Azusa N. Hattori
  • ,
  • Kenji Watanabe
  • ,
  • Takashi Taniguchi
  • ,
  • Yutaka Wakayama
  • ,
  • Keiji Ueno
  • ,
  • Hidekazu Tanaka

11
開始ページ
36871
終了ページ
36879
DOI
10.1021/acsami.9b13763

© 2019 American Chemical Society. Phase-transition field-effect transistors (FETs) are a class of steep-slope devices that show abrupt on/off switching owing to the metal-insulator transition (MIT) induced in the contacting materials. An important avenue to develop phase-transition FETs is to understand the charge injection mechanism at the junction of the contacting MIT materials and semiconductor channels. Here, toward the realization of high-performance phase-transition FETs, we investigate the contact properties of heterojunctions between semiconducting transition-metal dichalcogenides (TMDCs) and vanadium dioxide (VO2) that undergoes a MIT at a critical temperature (Tc) of approximately 340 K. We fabricated transistors based on molybdenum disulfide (MoS2) and tungsten diselenide (WSe2) in contact with the VO2 source/drain electrodes. The VO2-contacted MoS2 transistor exhibited n-type transport both below and above Tc. Across the MIT, the on-current was observed to increase only by a factor of 5, in contrast to the order-of-magnitude change in the resistance of the VO2 electrodes, suggesting the existence of high contact resistance. The Arrhenius analyses of the gate-dependent drain current confirmed the formation of the interfacial barrier at the VO2/MoS2 contacts, irrespective of the phase state of VO2. The VO2-contacted WSe2 transistor showed ambipolar transport, indicating that the Fermi level lies near the mid gap of WSe2. These observations provide insights into the contact properties of phase-transition FETs based on VO2 and TMDCs and suggest the need for contact engineering for high-performance operations.

リンク情報
DOI
https://doi.org/10.1021/acsami.9b13763
PubMed
https://www.ncbi.nlm.nih.gov/pubmed/31525896
Scopus
https://www.scopus.com/record/display.uri?eid=2-s2.0-85072957336&origin=inward
URL
https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85072957336&origin=inward