Tunable phase junctions in Bi2O3–BiVO4 thin films via reactive magnetron Co-sputtering for efficient carrier separation and enhanced photoelectrochemical performance

Sharifi, Tayebeh; Salamon, Krešimir; Mohammadi, Tecush; Jozić, Dražan; Peter, Robert; Arah, Bor; Lapanje, Aleš; Štrok, Marko (2026) Tunable phase junctions in Bi2O3–BiVO4 thin films via reactive magnetron Co-sputtering for efficient carrier separation and enhanced photoelectrochemical performance. Journal of Physics and Chemistry of Solids, 209 . ISSN 0022-3697

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Official URL: http://doi.org/10.1016/j.jpcs.2025.113300

Abstract

Engineering efficient photoelectrodes requires precise control over the structure, interfaces, and optoelectronic properties of thin semiconductor films. Here, reactive magnetron co-sputtering (RMS), combined with post-deposition annealing, was used to achieve in situ formation of Bi2O3–BiVO4 thin films with tunable phase composition and p–n heterojunctions. Unlike conventional wet-chemical methods, this approach allows direct control of Bi/V ratios during deposition, while annealing governs phase evolution on the substrate. By adjusting the Bi/V target power ratio and annealing temperature, Bi2O3–dominant, pure BiVO4, and mixed-phase Bi2O3–BiVO4 heterojunction films were synthesized, as confirmed by X-ray diffraction and X-ray photoelectron spectroscopy. High-temperature grazing incidence X-ray diffraction revealed phase transitions, with Bi2O3 stable at lower temperatures and BiVO4 forming above ∼400 °C. Photoelectrochemical characterization showed that Bi2O3–BiVO4 heterojunction films outperform single-phase films, owing to enhanced charge separation driven by internal electric fields at the p–n interface. The optimized BO/BVO–1 film exhibited photocurrent densities 2.5–9 times higher than pure BiVO4, depending on applied bias. Electrochemical impedance spectroscopy indicated reduced charge transfer resistance and suppressed recombination in the heterojunction samples. These findings demonstrate that RMS combined with annealing provides a scalable route for phase engineering and heterojunction design in thin-film photoelectrodes.

Item Type:

Article

Uncontrolled Keywords:

Magnetron co sputtering; Bi2O3; BiVO4; P–n hetrojunction; High-temperature grazing incidence X-ray diffraction (HT-GIXRD)

Subjects:

NATURAL SCIENCES > Physics
NATURAL SCIENCES > Chemistry

Divisions:

Division of Materials Physics

Projects: