N doping of TiO 2(110) Photoemission and density-functional studies

A. Nambu, J. Graciani, J. A. Rodriguez, Q. Wu, Etsuko Fujita, J. Fdez Sanz

Research output: Contribution to journalArticle

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Abstract

The electronic properties of N-doped rutile TiO 2(110) have been investigated using synchrotron-based photoemission and density-functional calculations. The doping via N 2 + ion bombardment leads to the implantation of N atoms (∼5% saturation concentration) that coexist with O vacancies. Ti 2p core level spectra show the formation of Ti 3+ and a second partially reduced Ti species with oxidation states between +4 and +3. The valence region of the TiO 2-xN y(110) systems exhibits a broad peak for Ti 3+ near the Fermi level and N-induced features above the O 2p valence band that shift the edge up by ∼0.5 eV. The magnitude of this shift is consistent with the "redshift" observed in the ultraviolet spectrum of N-doped TiO 2. The experimental and theoretical results show the existence of attractive interactions between the dopant and O vacancies. First, the presence of N embedded in the surface layer reduces the formation energy of O vacancies. Second, the existence of O vacancies stabilizes the N impurities with respect to N 2(g) formation. When oxygen vacancies and N impurities are together there is an electron transfer from the higher energy 3d band of Ti 3+ to the lower energy 2p band of the N 2- impurities.

Original languageEnglish
Article number094706
JournalJournal of Chemical Physics
Volume125
Issue number9
DOIs
Publication statusPublished - 2006

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Photoemission
Vacancies
photoelectric emission
Doping (additives)
Impurities
impurities
energy bands
Core levels
valence
Oxygen vacancies
Ion bombardment
Valence bands
Fermi level
Synchrotrons
Ion implantation
Electronic properties
Band structure
shift
Density functional theory
ultraviolet spectra

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

Cite this

Nambu, A., Graciani, J., Rodriguez, J. A., Wu, Q., Fujita, E., & Sanz, J. F. (2006). N doping of TiO 2(110) Photoemission and density-functional studies. Journal of Chemical Physics, 125(9), [094706]. https://doi.org/10.1063/1.2345062

N doping of TiO 2(110) Photoemission and density-functional studies. / Nambu, A.; Graciani, J.; Rodriguez, J. A.; Wu, Q.; Fujita, Etsuko; Sanz, J. Fdez.

In: Journal of Chemical Physics, Vol. 125, No. 9, 094706, 2006.

Research output: Contribution to journalArticle

Nambu, A, Graciani, J, Rodriguez, JA, Wu, Q, Fujita, E & Sanz, JF 2006, 'N doping of TiO 2(110) Photoemission and density-functional studies', Journal of Chemical Physics, vol. 125, no. 9, 094706. https://doi.org/10.1063/1.2345062
Nambu, A. ; Graciani, J. ; Rodriguez, J. A. ; Wu, Q. ; Fujita, Etsuko ; Sanz, J. Fdez. / N doping of TiO 2(110) Photoemission and density-functional studies. In: Journal of Chemical Physics. 2006 ; Vol. 125, No. 9.
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