Optical, mechanical, and dielectric properties of Bi1/2Na 1/2TiO3 thin film synthesized by sol-gel method

Chang Yeoul Kim, Tohru Sekino, Koichi Niihara

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)


The Bi1/2Na1/2TiO3 (BNT) thin film has been researched as an excellent candidate of lead-free ferroelectric materials. We synthesized BNT thin film on Si wafers or quartz glass by sol-gel spin coating method. The homogeneous and crack-free BNT thin film was synthesized by cost effective solution sol gel coating method. The main crystal phase of the film was identified as Bi1/2Na1/2TiO3. The BNT thin film which was coated 3 times and heat-treated at 700 °C had about 70% of transmittance in the ultra-violet visible (UV-VIS) light wavelength region. The calculated band gap energies from the UV transmittance spectra were 3.0 and 3.5 eV for indirect and direct transition, respectively and the refractive index of BNT thin film was 2.16 at 898 nm of wavelength. The hardness and elastic modulus of the film were about 9 and 136 GPa at 10 mN load, where the penetration depth was about 220 nm. BNT thin film showed the diffuse type of dielectric properties due to its Na+ and Bi3+ ions in A′1/2A″1/2BO3-type perovskite structure and the dielectric constant was about 10 until 300 °C and showed maximum value at 550 °C, 450 at 1 kHz.

Original languageEnglish
Pages (from-to)306-310
Number of pages5
JournalJournal of Sol-Gel Science and Technology
Issue number3
Publication statusPublished - 2010 Sep


  • Band gap energy
  • Dielectric
  • Nano-indentation
  • Raman spectroscopy
  • Sol-gel
  • Transmittance

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Chemistry(all)
  • Biomaterials
  • Condensed Matter Physics
  • Materials Chemistry


Dive into the research topics of 'Optical, mechanical, and dielectric properties of Bi1/2Na 1/2TiO3 thin film synthesized by sol-gel method'. Together they form a unique fingerprint.

Cite this