1. Phase Discrimination through Oxidant Selection in Low-Temperature Atomic Layer Deposition of Crystalline Iron Oxides
- Author
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Alex B. F. Martinson, Adam S. Hock, Joy M. Racowski, Jeffrey A. Klug, Shannon C. Riha, and Michael P. Lanci
- Subjects
Spinel ,Inorganic chemistry ,Iron oxide ,chemistry.chemical_element ,Surfaces and Interfaces ,engineering.material ,Condensed Matter Physics ,Oxygen ,chemistry.chemical_compound ,Atomic layer deposition ,chemistry ,Electrochemistry ,engineering ,Deposition (phase transition) ,General Materials Science ,Thin film ,Iron oxide cycle ,Spectroscopy ,Photocatalytic water splitting - Abstract
Control over the oxidation state and crystalline phase of thin-film iron oxides was achieved by low-temperature atomic layer deposition (ALD), utilizing a novel iron precursor, bis(2,4-methylpentadienyl)iron. This low-temperature (T = 120 °C) route to conformal deposition of crystalline Fe3O4 or α-Fe2O3 thin films is determined by the choice of oxygen source selected for the second surface half-reaction. The approach employs ozone to produce fully oxidized α-Fe2O3 or a milder oxidant, H2O2, to generate the Fe(2+)/Fe(3+) spinel, Fe3O4. Both processes show self-limiting surface reactions and deposition rates of at least 0.6 Å/cycle, a significantly high growth rate at such mild conditions. We utilized this process to prepare conformal iron oxide thin films on a porous framework, for which α-Fe2O3 is active for photocatalytic water splitting.
- Published
- 2013
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