Optical properties of amorphous Ba0.7Sr0.3TiO3 thin films obtained by metal organic decomposition technique

Zhimou Xu, Yuichiro Tanushi, Masato Suzuki, Keita Wakushima, Shin Yokoyama

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)


Barium strontium titanate (BaxSr1-x)TiO3 (BST) thin film deposition techniques are the subjects of many research studies mainly due to their influence on the optical and electrical properties of this material, which are of increasing interest for the processing of optoelectronic integrated circuits. In this study, the amorphous Ba0.7Sr0.3TiO3 (BST0.7) thin films were grown onto fused quartz and silicon substrates at low temperature by using a metal organic decomposition (MOD)-spin-coating procedure from barium 2-caprylate Ba(C8H15O2)2 and 3-methylbutyl acetate CH3COOC2H4CH(CH3)2-based special precursors. The optical constants of amorphous BST0.7 thin films including refractive index, extinction coefficient and optical band gap energies were presented. The calculated extinction coefficient of 214-nm-thick amorphous BST0.7 thin films in visible and near-infrared region was in the order of 10- 3, which is much lower than that of polycrystalline BST thin films. The optical band gap energy and refractive index n are estimated to be about 4.27 eV and n = 1.94, respectively. The optical propagation loss of the groove optical waveguide with 10 μm width and 185-nm-thick amorphous BST0.7 films was 4.11 dB/cm at a wavelength of 632.8 nm.

Original languageEnglish
Pages (from-to)2326-2331
Number of pages6
JournalThin Solid Films
Issue number4
Publication statusPublished - 2006 Dec 5
Externally publishedYes


  • Amorphous thin films
  • Barium strontium titanate
  • Optical constants
  • Optical waveguide

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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