Non-epitaxial integration of strain-tuned polycrystalline BiFeO3 thin films for silicon-based optoelectronics

Non-epitaxial integration of strain-tuned polycrystalline BiFeO3 thin films for silicon-based optoelectronics

Článek WoS

Integrating thin bismuth ferrite films with silicon-based platforms offers a promising path for advanced optoelectronic devices. This work investigates how oxygen partial pressure during pulsed laser deposition governs the structure, microstructure, defect chemistry, and optical properties of BiFeO3 films grown on Ti-buffered Si. Diffraction and microscopy confirm single-phase rhombohedral perovskite and indicate that the oxygen background tunes the lattice strain states and vacancy proxies. The lower-pressure film exhibits partial relaxed strain, finer grains, and a smaller oxygen-defect fraction, whereas the moderate-pressure film shows stronger tensile lattice strain, rougher grains, and a higher vacancy level. Spectroscopic ellipsometry results, analyzed with a multilayer model that includes buried Ti and TiOx interlayers, reveals distinct differences in dielectric dispersion and absorption edges. The lower-pressure film displays direct and indirect bandgaps of about 2.61 and 2.25 eV, while the moderate-pressure film shows slightly larger values of about 2.68 and 2.32 eV. These shifts are consistent with coupled variations in strain and oxygen-related disorder that modulate Fe-O bond lengths and hybridization. Overall, the results demonstrate that pressure-controlled strain and defect engineering can tailor light-matter interaction in Si-integrated BiFeO3 films for photonic and optoelectronic applications.

Integrating thin bismuth ferrite films with silicon-based platforms offers a promising path for advanced optoelectronic devices. This work investigates how oxygen partial pressure during pulsed laser deposition governs the structure, microstructure, defect chemistry, and optical properties of BiFeO3 films grown on Ti-buffered Si. Diffraction and microscopy confirm single-phase rhombohedral perovskite and indicate that the oxygen background tunes the lattice strain states and vacancy proxies. The lower-pressure film exhibits partial relaxed strain, finer grains, and a smaller oxygen-defect fraction, whereas the moderate-pressure film shows stronger tensile lattice strain, rougher grains, and a higher vacancy level. Spectroscopic ellipsometry results, analyzed with a multilayer model that includes buried Ti and TiOx interlayers, reveals distinct differences in dielectric dispersion and absorption edges. The lower-pressure film displays direct and indirect bandgaps of about 2.61 and 2.25 eV, while the moderate-pressure film shows slightly larger values of about 2.68 and 2.32 eV. These shifts are consistent with coupled variations in strain and oxygen-related disorder that modulate Fe-O bond lengths and hybridization. Overall, the results demonstrate that pressure-controlled strain and defect engineering can tailor light-matter interaction in Si-integrated BiFeO3 films for photonic and optoelectronic applications.

Bandgap, Bismuth ferrite, Ellipsometry, Heterostructures, Strain, Vacancy

Bandgap, Bismuth ferrite, Ellipsometry, Heterostructures, Strain, Vacancy

FAWAEER, S.; AL-QAISI, W.; SEDLÁKOVÁ, V.; MOUSA, M.; KNÁPEK, A.; SOBOLA, D.

2026

01.01.2026

Optical materials

169

1

Nizozemsko

9

https://www.sciencedirect.com/science/article/abs/pii/S0925346725009371?via%3Dihub