FeO(1 1 1) formation by exposure of Fe(1 1 0) to atomic and molecular oxygen

• Published in: Surface science 2006-07, Vol.600 (13), p.2778-2784
• Main Authors: Busch, M., Gruyters, M., Winter, H.
• Format: Article
• Language: English
• Subjects: Channeling; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Ion–solid interactions; Iron oxide; Molecular beam epitaxy; Oxidation; Physics
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/j.susc.2006.05.003

The growth, structure, and morphology of ultrathin iron oxide layers formed on a Fe(1 1 0) single crystal surface are investigated by Auger electron spectroscopy, low energy electron diffraction, and grazing ion scattering. For Fe oxidation by atomic instead of molecular oxygen, the gas exposure can be reduced by almost two orders of magnitude because surface sticking and dissociation are not limiting the growth process. A well-ordered FeO(1 1 1) film with low defect density is only obtained with atomic oxygen. Compared to the bulk, the FeO lattice is laterally compressed by about 5–6% resulting in an in-plane oxygen (Fe) nearest-neighbor distance of 2.87 Å. Independent of the preparation method, long-range structural order is poor if the oxide film thickness is increased to 3–5 layers. This is attributed to the relatively large lattice mismatch between FeO(1 1 1) and Fe(1 1 0).