Preperation and photocurrent properties of (Pb0.72,Ca0.28)TiO3 thin film capacitors fabricated by a sol-gel method

Ferroelectric (Pb-0.72,Ca-0.28)TiO3 (PCT) thin films were prepared on Pt/Ti/SiO2/Si substrates by a sol-gel method. To know the optimum annealing conditions, we measured the X-ray diffraction patterns and the capacitance-voltage characteristics for the PCT films prepared at the various temperatures between 450 degrees C and 700 degrees C. The film annealed at 650 degrees C for 30 minutes showed good ferroelectric properties. The saturation polarization, remanent polarization, and coercive field for this film were about 33 mu C/cm(2), 19 mu C/cm(2), and 120 kV/cm, respectively. According to the photon energy dependence of photocurrent for the PCT film, the band gap energy of the film was about 3.1 eV.