Metal-insulator transition of valence-controlled VO2 thin film prepared by RF magnetron sputtering using oxygen radical

Takaaki Suetsugu, Yuichi Shimazu, Takashi Tsuchiya, Masaki Kobayashi, Makoto Minohara, Enju Sakai, Koji Horiba, Hiroshi Kumigashira, Tohru Higuchi

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

We have prepared b-axis-oriented VO2 thin films by RF magnetron sputtering using oxygen radicals as the reactive gas. The VO2 thin films consist of a mixed-valence V3+/V4+ state formed by oxygen vacancies. The V3+ ratio strongly depends on the film thickness and the oxygen partial pressure of the radical gun during deposition. The lattice constant of the b-axis increases and the metal-insulator transition (MIT) temperature decreases with decreasing V3+ ratio, although the VO2 thin films with a high V3+ ratio of 42% do not exhibit MIT. The bandwidths and spectral weights of V 3d a1g and e g bands at around the Fermi level, which correspond to the insulating phase at 300 K, are smaller in the VO2 thin films with a low V3+ ratio. These results indicate that the control of the mixed-valence V3+/V4+ state is important for the MIT of b-axis-oriented VO2 thin films.

Original languageEnglish
Article number06GJ11
JournalJapanese journal of applied physics
Volume55
Issue number6
DOIs
Publication statusPublished - 2016 Jun
Externally publishedYes

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

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