Tailoring breakdown strength and energy-storage performance of silicon-integrated lead-free epitaxial BZT thin films through multi-element B-site substitutions

• Published in: Journal of alloys and compounds 2025-01, Vol.1010, p.177433, Article 177433
• Main Authors: Nguyen, M.D., Vo, D.D., Vu, T.V., Ho, T.H., Tong, H.D.
• Format: Article
• Language: English
• Subjects: Defect dipoles; Energy storage; Epitaxial film; High-temperature capacitor; Multi-element doping
• ISSN: 0925-8388
• DOI: 10.1016/j.jallcom.2024.177433

Developing high-temperature dielectric thin films with high-performance energy-storage properties for harsh environment applications has received increased attention. Herein, a multi-element co-doping strategy is proposed to enhance the breakdown strength and energy storage properties of lead-free BaTiO3-based thin films, which were deposited on silicon substrates using pulsed laser deposition. Due to the difference in ionic radii and valence states between the multi-dopants and host Ti-cations, the local lattice distortion and local charged defects are induced, which results in the reduction in the size of polar nanoregions (PNRs) and weakened coupling interactions between these PNRs, thus achieving stronger breakdown strength (EBD). Accordingly, owing to an enhanced EBD of 7.8 MV/cm and a delayed polarization saturation, a superior recoverable energy-storage density (Ur) of 140.8 J/cm3 along with an excellent energy efficiency (η) of 93.2 % were achieved at room temperature in the multi-element doped Ba(Zr0.2Ti0.2Mn0.2Nb0.2Sm0.2)O3 (BZTMNS) thin film. Moreover, the BZTMNS thin film also exhibits an excellent Ur of 102.6 J/cm3, a good η of 86.4 %, and a high EBD of 6.6 MV/cm at an operating temperature of 200 °C. Additionally, a small fluctuation of Ur (-6.1 %) and η (-11.7 %) values can also be observed in BZTMNS thin film in high cycling endurance, up to 1010 cycles, even when operated at an elevated temperature of 200 °C. These findings in the BZTMNS thin film demonstrate a feasible way to design high-temperature capacitors for modern electronic devices for hybrid vehicles and underground oil/gas explorations. [Display omitted] •Enhanced breakdown-strength achieved in the multi-element B-site doped films.•Epitaxial film shows a higher energy-storage performance than polycrystalline film.•High energy-storage density of 140.8 J/cm3 achieved in epitaxial BZTMNS films.•Excellent cycling endurance of energy-storage performance at temperature of 200 oC.