Spectral identification scheme for epitaxially grown single-phase niobium dioxide

Journal Article · Mon Mar 07 00:00:00 EST 2016 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4942834· OSTI ID:22597028

Hadamek, Tobias; Posadas, Agham B.; Dhamdhere, Ajit; Smith, David J. ^[1]

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1. Department of Physics, Arizona State University, Tempe, Arizona 85287 (United States)

This publication describes how to distinguish under-oxidized and over-oxidized phases of the metal-insulator transition material NbO{sub 2} by employing a combination of the Nb 3d and O 1s core-level and valence-band spectra. Niobium oxides (NbO{sub x}) are grown under various conditions by molecular beam epitaxy on several different substrates, mostly (111)-oriented strontium titanate (SrTiO{sub 3}), in order to obtain phase-pure NbO{sub 2}. The films are characterized by in situ reflection high-energy electron diffraction, X-ray diffraction, and transmission electron microscopy to determine crystallinity, lattice constants, and epitaxial relationships. Niobium metal oxidation states and film stoichiometry are determined with in situ X-ray photoelectron spectroscopy. Asymmetric Nb 3d core-level spectral components are observed in phase-pure NbO{sub 2}, with a binding energy for Nb 3d{sub 5/2} of 206 eV. The effect of substrate type, growth temperature, and oxygen pressure on the film composition is also described.

• OSTI ID: 22597028
• Journal Information: Journal of Applied Physics, Vol. 119, Issue 9; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ASYMMETRY
BINDING ENERGY
ELECTRON DIFFRACTION
FILMS
LATTICE PARAMETERS
MOLECULAR BEAM EPITAXY
MOLECULAR BEAMS
NIOBIUM OXIDES
OXIDATION
OXYGEN
PHASE TRANSFORMATIONS
REFLECTION
SPECTRA
STOICHIOMETRY
STRONTIUM TITANATES
SUBSTRATES
TRANSMISSION ELECTRON MICROSCOPY
VALENCE
X-RAY DIFFRACTION
X-RAY PHOTOELECTRON SPECTROSCOPY