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Title: Structural perturbations of epitaxial α-(Fe1-xVx)2O3 thin films driven by excess oxygen near the surface

We examine the structure and composition of phase-pure epitaxial α-(Fe1-xVx)2O3 thin films deposited on α-Al2O3(0001) substrates by oxygen-plasma-assisted molecular beam epitaxy for 0 ≤ x ≤ ~0.5. The films crystallize in the corundum lattice, with vanadium substituting for iron throughout. Vanadium cations exhibit the expected 3+ charge state in the bulk, but exhibit higher valences nearer to the surface, most likely because of excess oxygen in interstitial sites near the surface. The extent of vanadium oxidation beyond the 3+ state is inversely proportional to x. The gradation of vanadium valence with depth may have an impact on local bonding geometries, and could be highly significant in this material’s efficiency as a photocatalyst.
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Publication Date:
OSTI Identifier:
Report Number(s):
48144; KC0304030
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics, 116(23):Article No. 233702
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org:
Country of Publication:
United States
N06266; N00784; Environmental Molecular Sciences Laboratory