Preparation of transparent ferroelectric Pb_(0.92)La_(0.08)Ti_(0.96)O_3 thick films on ITO-coated glass substrates by a sol-gel route

摘要

Pb_(0.92)La_(0.08)Ti_(0.96)O_3 films with thickness between 580 nm and 1830 run were deposited on ITO-coated glass substrates using a sol-gel process under a relative low temperature of 580 deg C. The films are crystallized well and of pure perovskite polycrystalline structure, and the surface of the films was smooth and condense. With the increase of the film thickness, the grain size and dielectric, constants of the films increase. The dielectric constant-voltage curves are symmetric about a zero-bias axis and showed the hysteresis for at the films. In addition, the coercive field E_c decreases with the film thickness. All the films are transparent and the absoiption edges were found to shift to longer wavelength with increasing thickness of the films. The refractive index (n) and extinction coefficient (k) of 1830 nm thick film are 2.39 and 0.009, respectively, at 633 nm wavelength.