title: Atomic layer deposition of metastable β-Fe₂O₃ via isomorphic epitaxy for photoassisted water oxidation.
abstract: We report the growth and photoelectrochemical (PEC) characterization of the uncommon bibyite phase of iron(III) oxide (β-Fe2O3) epitaxially stabilized via atomic layer deposition on an conductive, transparent, and isomorphic template (Sn-doped In2O3). As a photoanode, unoptimized β-Fe2O3 ultrathin films perform similarly to their ubiquitous α-phase (hematite) counterpart, but reveal a more ideal bandgap (1.8 eV), a ∼0.1 V improved photocurrent onset potential, and longer wavelength (>600 nm) spectral response. Stable operation under basic water oxidation justifies further exploration of this atypical phase and motivates the investigation of other unexplored metastable phases as new PEC materials.
authors.affiliation: Materials Science Division and ‡X-ray Science Division, Argonne National Laboratory , 9700 South Cass Avenue, Argonne, Illinois 60439, United States.
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Emery
authors.forename: Christian M
authors.initials: CM
authors.lastname: Schlepütz
authors.forename: Peijun
authors.initials: P
authors.lastname: Guo
authors.forename: Shannon C
authors.initials: SC
authors.lastname: Riha
authors.forename: Robert P H
authors.initials: RP
authors.lastname: Chang
authors.forename: Alex B F
authors.initials: AB
authors.lastname: Martinson
keywords: PEC water oxidation; atomic layer deposition; epitaxial stabilization; iron(III) oxide; α-Fe2O3; β-Fe2O3