Large and constant absorption coefficient in Nb x Ti 1− x O 2 thin films throughout the visible range

Adam E. Shimabukuro, Akihiro Ishii, Itaru Oikawa, Yusuke Yamazaki, Masaaki Imura, Toshimasa Kanai, Fumio S. Ohuchi, Hitoshi Takamura

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

We investigated the optical absorption properties of Nb x Ti 1−x O 2 thin films, a solid solution combining the reduced titanium and niobium oxide phases TiO 2 and NbO 2. The optical absorption properties of Nb x Ti 1−x O 2 thin films prepared by pulsed laser deposition at 600 °C were shown to be large in magnitude at an almost constant value of ≈17 µm −1 . Because this large absorption coefficient is nearly independent of incident photon energy in the visible range (400–700 nm), the Nb x Ti 1−x O 2 thin films appear optically black. Flat and homogenous, optically black coatings like these are desirable for color isolation in flat panel displays. The origin of flat wavelength dispersion in Nb x Ti 1−x O 2 is the coexistence of semiconducting absorption and metallic light absorption mechanisms. Localized Nb-Nb dimers in the metallic Nb x Ti 1−x O 2 phase open an optical band gap which gives rise to semiconducting behavior. We show here that reduction results in strong visible light sensitization in normally transparent Nb-Ti oxides.

Original languageEnglish
Pages (from-to)61-67
Number of pages7
JournalApplied Surface Science
Volume464
DOIs
Publication statusPublished - 2019 Jan 15

Keywords

  • Absorption coefficient
  • NbO
  • Non-dispersive media
  • Pulsed laser deposition
  • Ti O

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Physics and Astronomy(all)
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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