Enhancement of ferroelectricity in perovskite BaTiO<sub>3</sub> epitaxial thin films by sulfurization
Sulfur is a promising anion dopant for exploring exotic physical phenomena in complex perovskite oxides. However, sulfurization to the epitaxial single-crystal oxide thin films with high crystallinity is experimentally challenging due to the volatility of sulfur element; thus, sulfurization effects...
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| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
AIMS Press
2024-09-01
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| Series: | AIMS Materials Science |
| Subjects: | |
| Online Access: | https://www.aimspress.com/article/doi/10.3934/matersci.2024039?viewType=HTML |
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| Summary: | Sulfur is a promising anion dopant for exploring exotic physical phenomena in complex perovskite oxides. However, sulfurization to the epitaxial single-crystal oxide thin films with high crystallinity is experimentally challenging due to the volatility of sulfur element; thus, sulfurization effects on the associated properties have been scarcely studied. Here, we demonstrate an enhancement of ferroelectric polarization of epitaxial BaTiO<sub>3</sub> thin films by sulfur doping. Initially, the epitaxial BaTiO<sub>3</sub> thin films with high crystallinity were grown by pulsed laser deposition (PLD). Then, sulfurization to epitaxial BaTiO<sub>3</sub> films was performed using a precursor of thiourea (CH<sub>4</sub>N<sub>2</sub>S) solution via a spin-coating technique. The crystalline structure of sulfurized BaTiO<sub>3</sub> films was identified by X-ray diffraction (XRD) and scanning transmission electron microscopy (STEM). The structural distortion with the elongated out-of-plane lattice constant was observed in the sulfurized BaTiO<sub>3</sub> films. Atomic force microscopy (AFM) analyses also confirmed the surface morphology of films after sulfurization. Interestingly, we found an enhanced ferroelectric polarization in sulfur-doped BaTiO<sub>3</sub> films accompanying the improved tetragonality in the crystal structure after sulfurization. The increments in the remnant (~34.8%) and saturated (~30.6%) polarizations of sulfurized BaTiO<sub>3</sub> films were obtained in comparison with pure BaTiO<sub>3</sub> films. Our work could be a primary study for a thorough understanding of the sulfur doping effect in perovskite oxides, opening up the potential of oxysulfide materials. |
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| ISSN: | 2372-0484 |