Annealing Temperature and Ultraviolet Irradiation Effect on the Ferroelectric Properties of Bi_(3.25)La_(0.75)Ti_3O_(12) Thin Films

摘要

Bi_(3.25)La_(0.75)Ti_3O_(12) thin films were prepared on Pt/Ti/SiO_2/Si substrates by the metal organic decomposition method. The structural characterizations and the surface morphology observations were carried out applying X-ray diffraction and atomic force microscope, respectively. The annealing temperature and the ultraviolet irradiation effect on the ferroelectric properties were studied. It was found that the remnant polarization (P_r) and the coercive field (E_c) increased with the increase of the applied electric field (E) for all films. With the annealing temperature increasing from 670℃ to 750℃, the increase tendency of P_r(E) and E_c (E) got enhanced from 670℃ to 720℃, followed by weakened from 720℃ at 750℃. These phenomena could be well explained by the different internal strain in films. The remnant polarization and the coercive field showed an obvious decrease when the top electrodes of the thin films were illuminated with UV light due to the screening effect of trapped charge carries.