Epitaxy of polar semiconductor Co3O4 (110): Growth, structure, and characterization

Kristy J. Kormondy, Agham B. Posadas, Alexander Slepko, Ajit Dhamdhere, David Smith, Khadijih N. Mitchell, Travis I. Willett-Gies, Stefan Zollner, Luke G. Marshall, Jianshi Zhou, Alexander A. Demkov

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14 Scopus citations


The (110) plane of Co3O4 spinel exhibits significantly higher rates of carbon monoxide conversion due to the presence of active Co3+ species at the surface. However, experimental studies of Co3O4 (110) surfaces and interfaces have been limited by the difficulties in growing high-quality films. We report thin (10-250 Å) Co3O4 films grown by molecular beam epitaxy in the polar (110) direction on MgAl2O4 substrates. Reflection high-energy electron diffraction, atomic force microscopy, x-ray diffraction, and transmission electron microscopy measurements attest to the high quality of the as-grown films. Furthermore, we investigate the electronic structure of this material by core level and valence band x-ray photoelectron spectroscopy, and first-principles density functional theory calculations. Ellipsometry reveals a direct band gap of 0.75 eV and other interband transitions at higher energies. A valence band offset of 3.2 eV is measured for the Co3O 4/MgAl2O4 heterostructure. Magnetic measurements show the signature of antiferromagnetic ordering at 49 K. FTIR ellipsometry finds three infrared-active phonons between 300 and 700 cm 1.

Original languageEnglish (US)
Article number243708
JournalJournal of Applied Physics
Issue number24
Publication statusPublished - Jun 28 2014


ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Kormondy, K. J., Posadas, A. B., Slepko, A., Dhamdhere, A., Smith, D., Mitchell, K. N., ... Demkov, A. A. (2014). Epitaxy of polar semiconductor Co3O4 (110): Growth, structure, and characterization. Journal of Applied Physics, 115(24), [243708]. https://doi.org/10.1063/1.4885048