Insights into the Characteristic Gap Level and n-Type Conductivity of Rutile TiO 2 from the Hybrid Functional Method

Xiaoping Han, Noureddine Amrane, Zongsheng Zhang, Maamar Benkraouda

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


Using the Heyd-Scyseria-Ernzerhof (HSE) hybrid functional in the framework of the density functional theory (DFT), we probe the insight into the characteristic gap level and n-type conductivity of the intrinsic rutile TiO 2 . Thermodynamic and kinetic investigations have been conducted to elaborate the favorability for the formation of the possible n-type defects and unintentional impurities in rutile TiO 2 . Results show that oxygen vacancy is clearly identified to induce a deep localized state inside the forbidden energy region through localizing two excess electrons at two Ti 4+ ions along the [001] direction and reducing them into Ti 3+ ions, accounting for the characteristic gap level observed experimentally. The e g orbital composition of this gap level offers an accountable explanation of the experimentally measured ferromagnetism in TiO 2-x , while the electron transition from this characteristic level is contributable to the photocatalytic behaviors and visible photoluminescence of slightly reduced TiO 2 . Also, unintentional incorporation of hydrogen substitution for oxygen acts as a shallow donor, providing a consistent explanation of the n-type conductivity in TiO 2 . The fundamental understanding of these characteristic properties and the associated functionalities would be essential to improving and expanding the practical applications of TiO 2 -based materials and devices.

Original languageEnglish
Pages (from-to)2037-2047
Number of pages11
JournalJournal of Physical Chemistry C
Issue number4
Publication statusPublished - Jan 31 2019

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • General Energy
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films


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