[2D12-21] Surface Science (SS1) Physical Property

3:00 PM - 3:15 PM JST(6:00 AM - 6:15 AM UTC)

[2D14] Correlating TiO₂ electronic structure with band Alignment in Mo:BiVO₄/TiO₂ oxide heterojunctions

*Lingga Ghufira Oktariza^1,2, Kenichi Ozawa^1,2, Kazuhiko Mase^1,2, Takeaki Sakurai³ (1. Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK) (Japan), 2. Graduate University of Advanced Studies (SOKENDAI) (Japan), 3. Institute of Pure and Applied Sciences, University of Tsukuba (Japan))

Band alignment at oxide heterointerfaces plays a key role in charge transport and carrier separation, yet its relationship with the electronic structure of TiO₂ remains insufficiently understood. This study investigates the effect of oxygen partial pressure during RF sputtering on the electronic structure of TiO₂ and its correlation with band alignment in Mo:BiVO₄/TiO₂ oxide heterojunctions. Ultraviolet photoelectron spectroscopy revealed systematic changes in the work function and valence-band maximum with increasing oxygen partial pressure, indicating suppression of donor-like electronic states in oxygen-deficient TiO₂. These electronic structure changes reduced the Fermi-level mismatch, leading to improved band alignment, a lower onset potential, and enhanced photoelectrochemical performance. This work establishes a direct correlation between UPS-derived electronic structure and heterojunction band alignment, providing a surface-science perspective for rational oxide heterointerface design.

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