TY - JOUR
T1 - Spectral identification scheme for epitaxially grown single-phase niobium dioxide
AU - Hadamek, Tobias
AU - Posadas, Agham B.
AU - Dhamdhere, Ajit
AU - Smith, David
AU - Demkov, Alexander A.
N1 - Funding Information:
This work was supported by the Semiconductor Research Corporation under Contract No. 2012-VJ-2299. We thank Ilya Karpov, Andrew O''Hara, Chungwei Lin, and Stefan Zollner for many insightful discussions during this work. We gratefully acknowledge the use of facilities in the John M. Carley Center for High Resolution Electron Microscopy at Arizona State University.
Publisher Copyright:
© 2016 AIP Publishing LLC.
Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2016/3/7
Y1 - 2016/3/7
N2 - This publication describes how to distinguish under-oxidized and over-oxidized phases of the metal-insulator transition material NbO2 by employing a combination of the Nb 3d and O 1s core-level and valence-band spectra. Niobium oxides (NbOx) are grown under various conditions by molecular beam epitaxy on several different substrates, mostly (111)-oriented strontium titanate (SrTiO3), in order to obtain phase-pure NbO2. 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 NbO2, with a binding energy for Nb 3d5/2 of 206 eV. The effect of substrate type, growth temperature, and oxygen pressure on the film composition is also described.
AB - This publication describes how to distinguish under-oxidized and over-oxidized phases of the metal-insulator transition material NbO2 by employing a combination of the Nb 3d and O 1s core-level and valence-band spectra. Niobium oxides (NbOx) are grown under various conditions by molecular beam epitaxy on several different substrates, mostly (111)-oriented strontium titanate (SrTiO3), in order to obtain phase-pure NbO2. 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 NbO2, with a binding energy for Nb 3d5/2 of 206 eV. The effect of substrate type, growth temperature, and oxygen pressure on the film composition is also described.
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U2 - 10.1063/1.4942834
DO - 10.1063/1.4942834
M3 - Article
AN - SCOPUS:84960153341
SN - 0021-8979
VL - 119
JO - Journal of Applied Physics
JF - Journal of Applied Physics
IS - 9
M1 - 095308
ER -