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Title: Defects, stoichiometry, and electronic transport in SrTiO 3-δ epilayers: A high pressure oxygen sputter deposition study

Authors:
; ORCiD logo; ; ; ORCiD logo; ; ORCiD logo;
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: 2016-12-26 03:08:26; 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 SrTiO 3-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 SrTiO 3-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. 2016. "Defects, stoichiometry, and electronic transport in SrTiO 3-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 SrTiO 3-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 = 2016,
month = 8
}

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

Citation Metrics:
Cited by: 1work
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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
  • We have investigated the properties of interfaces between LaAlO{sub 3} films grown on SrTiO{sub 3} substrates singly terminated by TiO{sub 2}. We used RF sputtering in a high-pressure oxygen atmosphere. The films are smooth, with flat surfaces. Transmission electron microscopy shows sharp and continuous interfaces with some slight intermixing. The elemental ratio of La to Al, measured by the energy dispersive X-ray technique, is found to be 1.07. Importantly, we find these interfaces to be non-conducting, indicating that the sputtered interface is not electronically reconstructed in the way reported for films grown by pulsed laser deposition because of the differentmore » interplays among stoichiometry, mixing, and oxygen vacancies.« 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
  • In many transition metal oxides, oxygen stoichiometry is one of the most critical parameters that plays a key role in determining the structural, physical, optical, and electrochemical properties of the material. However, controlling the growth to obtain high quality single crystal films having the right oxygen stoichiometry, especially in a high vacuum environment, has been viewed as a challenge. In this work, we show that, through proper control of the plume kinetic energy, stoichiometric crystalline films can be synthesized without generating oxygen defects even in high vacuum. We use a model homoepitaxial system of SrTiO 3 (STO) thin films onmore » single crystal STO substrates. Physical property measurements indicate that oxygen vacancy generation in high vacuum is strongly influenced by the energetics of the laser plume, and it can be controlled by proper laser beam delivery. Thus, our finding not only provides essential insight into oxygen stoichiometry control in high vacuum for understanding the fundamental properties of STO-based thin films and heterostructures, but it expands the utility of pulsed laser epitaxy of other materials as well.₃« less
  • Oxidation of silicon during the growth of silicon oxide by ion beam sputter deposition was studied by in situ x-ray photoelectron spectroscopy as a function of oxygen partial pressure at various deposition temperatures below 600 deg. C. At low temperatures, the variation of incorporated oxygen content is similar to a dissociative adsorption isotherm of O{sub 2} on Si indicating that the surface-confined reaction of the deposited Si atoms with the adsorbed oxygen atoms is the main process. However, it shows a three-step variation with the oxygen partial pressure at high temperatures. The evolution of SiO species confirmed by the XPSmore » indicates that an adsorption-induced surface reaction and a diffusion-induced internal reaction are the main pathways for the Si oxidation.« less