Effect of an in-situ applied electric field on growth of Bi4Ti3O12 films by sol-gel

Bi4Ti3O12 (BIT) films were prepared on Pt/TiO2/SiO2/Si substrates by the sol-gel method. A low electric field was in-situ applied to BIT films during rapid thermal annealing (RTA). It was first found that a bias electric field has great influence on the structure, orientation, and morphology of BIT films at proper temperatures. Under the electric field of very low V/cm, BIT films show highly c-axis-oriented growth with second phase of bismuth oxide at 600 and 650 °C. The possible origin is proposed. On one hand, the electrostatic energy provides an extra driving force and the co-interaction of the electrostatic energy and interface energy promotes the c-axis-oriented growth of the BIT grains. On the other hand, the second phase of bismuth oxide produced during RTA in an electric field also plays an important role in the control of film orientation.