Synthesis of epitaxial films of Fe{sub 3}O{sub 4} and {alpha}-Fe{sub 2}O{sub 3} with various low-index orientations by oxygen-plasma-assisted molecular beam epitaxy

Journal Article · Sat Mar 01 04:00:00 EST 1997 · Journal of Vacuum Science and Technology, A

DOI:https://doi.org/10.1116/1.580488· OSTI ID:467286

Gao, Y; Kim, Y J; Chambers, S A ^[1]; Bai, G ^[2]

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1. Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States)
2. Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

Epitaxial thin films of pure-phase Fe{sub 3}O{sub 4}(110), Fe{sub 3}O{sub 4}(111), {alpha}-Fe{sub 2}O{sub 3}(11{bar 2}0), and {alpha}-Fe{sub 2}O{sub 3}(1{bar 1}02) have been grown on MgO(110), {alpha}-Al{sub 2}O{sub 3}(0001), {alpha}-Al{sub 2}O{sub 3}(11{bar 2}0), and {alpha}-Al{sub 2}O{sub 3}(1{bar 1}02) substrates, respectively, by molecular beam epitaxy using an elemental Fe source and an electron cyclotron resonance oxygen plasma source. Characterization of the crystal structures, chemical states, and epitaxial relationships was carried out using a variety of techniques, including {ital in situ} reflection high-energy electron diffraction (RHEED), low-energy electron diffraction, x-ray photoelectron spectroscopy/diffraction, and {ital ex situ} x-ray reflectivity and diffraction. Real-time RHEED reveals that Fe{sub 3}O{sub 4} growth on MgO appears in a step-flow fashion, whereas the growth of Fe{sub 3}O{sub 4}(111) on {alpha}-Al{sub 2}O{sub 3}(0001) occurs initially by island formation, and then island coalescence. However, the growth of {alpha}-Fe{sub 2}O{sub 3} on {alpha}-Al{sub 2}O{sub 3} appears to follow an intermediate growth mode. The formation of pure-phase films is controlled largely by oxygen partial pressure, plasma power, and growth rate, but appears to be independent of growth temperature, at least from 250 to 550{degree}C. The present study demonstrates that selective growth of pure-phase iron oxides with various low-index orientations can be achieved by controlling the growth conditions and selecting suitable substrates. {copyright} {ital 1997 American Vacuum Society.}

• Research Organization: Pacific Northwest National Laboratory
• DOE Contract Number: AC06-76RL01830
• OSTI ID: 467286
• Journal Information: Journal of Vacuum Science and Technology, A, Journal Name: Journal of Vacuum Science and Technology, A Journal Issue: 2 Vol. 15; ISSN JVTAD6; ISSN 0734-2101
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
40 CHEMISTRY
CHEMICAL BONDS
CRYSTAL GROWTH
CRYSTAL STRUCTURE
ELECTRON DIFFRACTION
IRON OXIDES
MOLECULAR BEAM EPITAXY
PHOTOELECTRON SPECTROSCOPY
PLASMA
THIN FILMS
X-RAY DIFFRACTION