Structure, dielectric, ferroelectric, and optical properties of (1-x)Ba(Zr0.2Ti0.8)O3-x(Ba0.7Ca0.3)TiO3 thin films prepared by sol-gel method

We report high dielectric tunabilities of (1-x)Ba(Zr0.2Ti0.8)O-3-x(Ba0.7Ca0.3)TiO3 (BZT-xBCT) (x=0.15, 030, 0.40, 0.45, 0.50, and 0.55) thin films prepared by a sol-gel method. The films show a pure perovskite structure with random orientation. They have moderate dielectric constant ranging from 350 to 500 and low dielectric loss near 3.0% at 1 kHz with 0 V bias at room temperature. The dielectric tunability of the BZT-0.55BCT thin films is up to 65% at 400 kV/cm and 100 kHz. The films exhibit a high optical transmission in the range of 420 nm-1500 nm. Their optical band gap energies are about 3.90 eV. (C) 2011 Elsevier B.V. All rights reserved.