Hydrothermal growth of c-axis oriented ferroelectric (Bi1/2K1/2)TiO3 films on metal substrates

Masayoshi Yamamoto, Ryotaro Sakurai, Manabu Hagiwara, Shinobu Fujihara

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


Ferroelectric films fabricated on metal substrates are desirable for use in piezoelectric vibration energy harvesters. In this report, we demonstrate that dense films of lead-free ferroelectric (Bi1/2K1/2)TiO3 (BKT) with preferred c-axis orientation can be grown on nickel-based alloy substrates by utilizing the hydrothermal synthesis method. A buffer layer of LaNiO3 (LN) was formed on the substrates by the sol-gel spin coating method, and then BKT was grown by a hydrothermal reaction at a low temperature of 150 °C. The surface structure and thickness of the final BKT films were found to strongly depend on the numbers of the deposition cycles for LN and BKT, respectively. As a result, highly c-axis oriented BKT films with a smooth surface and a thickness up to 830 nm were obtained. Although the as-deposited BKT films were suggested to contain hydroxyl groups in their crystal lattice, a post-annealing process at 650 °C in air was found to be effective to remove them. The polarization response of the annealed BKT film proved the ferroelectric polarization switching in the film.

Original languageEnglish
Article number138342
JournalThin Solid Films
Publication statusPublished - 2020 Nov 1


  • Ferroelectrics
  • Film growth
  • Hydrothermal method
  • Low-temperature synthesis
  • Metal substrates

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Materials Chemistry


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