Wardenga, Hans F. ; Klein, Andreas (2016)
Surface Potentials of (111), (110) and (100) oriented CeO2−x thin films.
In: Applied Surface Science, 377
doi: 10.1016/j.apsusc.2016.03.091
Artikel, Bibliographie
Kurzbeschreibung (Abstract)
Differently oriented CeO2 thin films were prepared by radio frequency magnetron sputter deposition from a nominally undoped CeO2 target. (111), (110) and (100) oriented films were achieved by deposition onto Al2O3(0001)/Pt(111), MgO(110)/Pt(110) and SrTiO3:Nb(100) substrates, respectively. Epitaxial growth is verified using X-ray diffraction analysis. The films were analyzed by in situ photoelectron spectroscopy to determine the ionization potential, work function, Fermi level position and Ce3+ concentration at the surface in dependence of crystal orientation, deposition conditions and post-deposition treatment in reducing and oxidizing atmosphere. We observed a very high variation of the work function and ionization potential of more than 2 eV for all surface orientations, while the Fermi level varies by only 0.3 eV within the energy gap. The work function generally decreases with increasing Ce3+ surface concentration but comparatively high Ce3+ concentrations remain even after strongly oxidizing treatments. This is related to the presence of subsurface oxygen vacancies.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2016 |
| Autor(en): | Wardenga, Hans F. ; Klein, Andreas |
| Art des Eintrags: | Bibliographie |
| Titel: | Surface Potentials of (111), (110) and (100) oriented CeO2−x thin films |
| Sprache: | Englisch |
| Publikationsjahr: | 2016 |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Applied Surface Science |
| Jahrgang/Volume einer Zeitschrift: | 377 |
| DOI: | 10.1016/j.apsusc.2016.03.091 |
| Kurzbeschreibung (Abstract): | Differently oriented CeO2 thin films were prepared by radio frequency magnetron sputter deposition from a nominally undoped CeO2 target. (111), (110) and (100) oriented films were achieved by deposition onto Al2O3(0001)/Pt(111), MgO(110)/Pt(110) and SrTiO3:Nb(100) substrates, respectively. Epitaxial growth is verified using X-ray diffraction analysis. The films were analyzed by in situ photoelectron spectroscopy to determine the ionization potential, work function, Fermi level position and Ce3+ concentration at the surface in dependence of crystal orientation, deposition conditions and post-deposition treatment in reducing and oxidizing atmosphere. We observed a very high variation of the work function and ionization potential of more than 2 eV for all surface orientations, while the Fermi level varies by only 0.3 eV within the energy gap. The work function generally decreases with increasing Ce3+ surface concentration but comparatively high Ce3+ concentrations remain even after strongly oxidizing treatments. This is related to the presence of subsurface oxygen vacancies. |
| Fachbereich(e)/-gebiet(e): | 11 Fachbereich Material- und Geowissenschaften 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Fachgebiet Oberflächenforschung |
| Hinterlegungsdatum: | 30 Mär 2016 10:57 |
| Letzte Änderung: | 05 Apr 2016 20:31 |
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