Preparation of Ca2Ti2O6 pyrochlore films by MOCVD

Yuanwei Zhang, Jie Yu, Rong Tu, Takashi Goto

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Abstract

Ca-Ti-O films were prepared on quartz substrates by MOCVD using the precursors of Ti(O-i-Pr)2(dpm)2 and Ca(dpm)2. The effects of deposition conditions on the crystal structure and microstructure of Ca-Ti-O films were investigated. The deposition temperatures (T dep) were changed from 787 to 1187 K and the total pressures in the reaction chamber (Ptot) was kept at 0.8 kPa. The molar ratio of Ca to Ti precursors (RCa/Ti) was changed from 0.34 to 0.95. At temperatures higher than 1073 K, CaTiO3 perovskite films in a single phase were obtained. Mixtures of Ca2Ti2O6 in a pyrochlore structure and CaTiO3 in a perovskite structure were obtained at 787 to 1073 K and the content of Ca2Ti2O 6 phase increased with decreasing RCa/Ti. Ca 2Ti2O6 pyrochlore films in a single phase were obtained at Tdep = 1073K and RCa/Ti = 0.38. Ca 2Ti2O6 is a face-centered cubic structure with a=0.990 nm. Pyrochlore showed a granular microstructure about 500 nm in grain size. The transmittance of the Ca2Ti2O6 films in a single phase was 50% to 70% in the wavelength range of 500 to 2500 nm. The band-gap of pyrochlore was about 3.3 eV that calculated by the transmittance. The permittivity of Ca2Ti2O6 films was about 100 from room temperature to 700K.

Original languageEnglish
Article number012032
JournalJournal of Physics: Conference Series
Volume152
DOIs
Publication statusPublished - 2009 Jan 1

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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