Electronic and optical properties of TaO1-xN1+x-based alloys

Nabil Al-Aqtash, Florin Apostol, Wai Ning Mei, Renat F. Sabirianov

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

TaON is considered as a potential candidate as a visible-light responsive photocatalyst. We report the results of ab initio studies of electronic structure of TaON-based alloys. Specifically, we show that the position of conduction and valence band can be modified by varying the oxygen and nitrogen concentrations in TaO1-xN1+x. We find that the band gap decreases monotonically with the increase of N/O ratio. The band gap energy is decreased in monoclinic TaON from near 2.3 eV to just over 1.7 eV (i.e., by 35%) when N/O ratio is increased from 3/5 to 5/3. Our calculations show that the band gap reduces in a series of experimentally fabricated alloys ZrTa 3O5N3→TaON→YTa7O 7N8. The band gap reduction is mostly associated with the change in the position of the valence band due to the hybridization of N 2p states, while the conduction band consisting mostly of Ta 5d-states is not sensitive to N content. The calculated optical absorption spectra show reduction in the optical band gap with increasing N/O ratio.

Original languageEnglish (US)
Pages (from-to)337-343
Number of pages7
JournalJournal of Solid State Chemistry
Volume198
DOIs
StatePublished - Feb 2013

Keywords

  • First-principles calculations on the electronic and optical properties
  • TaON-based alloys
  • Visible-light responsive photocatalyst

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

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