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Title: Defects, stoichiometry, and electronic transport in SrTiO3-δ epilayers: A high pressure oxygen sputter deposition study

Authors:
 [1]; ORCiD logo [1];  [2];  [1]; ORCiD logo [1];  [1]; ORCiD logo [1];  [1]
  1. Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA
  2. Characterization Facility, University of Minnesota, Minneapolis, Minnesota 55455, USA
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1282418
Grant/Contract Number:
FG02-06ER46275
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 120; Journal Issue: 5; Related Information: CHORUS Timestamp: 2018-03-09 11:35:16; Journal ID: ISSN 0021-8979
Publisher:
American Institute of Physics
Country of Publication:
United States
Language:
English

Citation Formats

Ambwani, P., Xu, P., Haugstad, G., Jeong, J. S., Deng, R., Mkhoyan, K. A., Jalan, B., and Leighton, C.. Defects, stoichiometry, and electronic transport in SrTiO3-δ epilayers: A high pressure oxygen sputter deposition study. United States: N. p., 2016. Web. doi:10.1063/1.4960343.
Ambwani, P., Xu, P., Haugstad, G., Jeong, J. S., Deng, R., Mkhoyan, K. A., Jalan, B., & Leighton, C.. Defects, stoichiometry, and electronic transport in SrTiO3-δ epilayers: A high pressure oxygen sputter deposition study. United States. doi:10.1063/1.4960343.
Ambwani, P., Xu, P., Haugstad, G., Jeong, J. S., Deng, R., Mkhoyan, K. A., Jalan, B., and Leighton, C.. Thu . "Defects, stoichiometry, and electronic transport in SrTiO3-δ epilayers: A high pressure oxygen sputter deposition study". United States. doi:10.1063/1.4960343.
@article{osti_1282418,
title = {Defects, stoichiometry, and electronic transport in SrTiO3-δ epilayers: A high pressure oxygen sputter deposition study},
author = {Ambwani, P. and Xu, P. and Haugstad, G. and Jeong, J. S. and Deng, R. and Mkhoyan, K. A. and Jalan, B. and Leighton, C.},
abstractNote = {},
doi = {10.1063/1.4960343},
journal = {Journal of Applied Physics},
number = 5,
volume = 120,
place = {United States},
year = {Thu Aug 04 00:00:00 EDT 2016},
month = {Thu Aug 04 00:00:00 EDT 2016}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1063/1.4960343

Citation Metrics:
Cited by: 2works
Citation information provided by
Web of Science

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  • SrTiO{sub 3} is not only of enduring interest due to its unique dielectric, structural, and lattice dynamical properties, but is also the archetypal perovskite oxide semiconductor and a foundational material in oxide heterostructures and electronics. This has naturally focused attention on growth, stoichiometry, and defects in SrTiO{sub 3}, one exciting recent development being such precisely stoichiometric defect-managed thin films that electron mobilities have finally exceeded bulk crystals. This has been achieved only by molecular beam epitaxy, however (and to a somewhat lesser extent pulsed laser deposition (PLD)), and numerous open questions remain. Here, we present a study of the stoichiometry,more » defects, and structure in SrTiO{sub 3} synthesized by a different method, high pressure oxygen sputtering, relating the results to electronic transport. We find that this form of sputter deposition is also capable of homoepitaxy of precisely stoichiometric SrTiO{sub 3}, but only provided that substrate and target preparation, temperature, pressure, and deposition rate are carefully controlled. Even under these conditions, oxygen-vacancy-doped heteroepitaxial SrTiO{sub 3} films are found to have carrier density, mobility, and conductivity significantly lower than bulk. While surface depletion plays a role, it is argued from particle-induced X-ray emission (PIXE) measurements of trace impurities in commercial sputtering targets that this is also due to deep acceptors such as Fe at 100's of parts-per-million levels. Comparisons of PIXE from SrTiO{sub 3} crystals and polycrystalline targets are shown to be of general interest, with clear implications for sputter and PLD deposition of this important material.« less
  • BaSnO{sub 3} has recently been identified as a high mobility wide gap semiconductor with significant potential for room temperature oxide electronics. Here, a detailed study of the high pressure oxygen sputter-deposition, microstructure, morphology, and stoichiometry of epitaxial BaSnO{sub 3} on SrTiO{sub 3}(001) and MgO(001) is reported, optimized conditions resulting in single-phase, relaxed, close to stoichiometric films. Most significantly, vacuum annealing is established as a facile route to n-doped BaSnO{sub 3−δ}, leading to electron densities above 10{sup 19} cm{sup −3}, 5 mΩ cm resistivities, and room temperature mobility of 20 cm{sup 2} V{sup −1} s{sup −1} in 300-Å-thick films on MgO(001).more » Mobility limiting factors, and the substantial scope for their improvement, are discussed.« less
  • Superconductivity with T c = 53.5 K has been induced in a large La₁.₉Ca₁.₁Cu₂O₆ (La-2126) single crystal by annealing in a high partial-pressure of oxygen at 1200°C. Using transmission electron microscopy (TEM) techniques, we show that a secondary Ca-doped La₂CuO₄ (La-214) phase, not present in the as-grown crystal, appears as a coherent “intergrowth” as a consequence of the annealing. A corresponding secondary superconducting transition near 13 K is evident in the magnetization measurement. In this study, electron energy loss spectroscopy (EELS) reveals a pre-edge peak at the O K edge in the superconducting La-2126 phase, which is absent in themore » as-grown crystal, confirming the hole-doping by interstitial oxygen.« less