Hydrothermal growth of highly textured BaTiO_3 films composed of nanowires

摘要

Textured barium titanate (BaTiO_3) films are attracting immense research interest due to their lead-free composition and excellent piezoelectric and dielectric properties. Most synthesis methods for these films require a high temperature, leading to the formation of a secondary phase and an overall decrease in the electrical properties of the ceramic. In order to alleviate these issues, a novel fabrication method is introduced by transferring oriented rutile TiO_2 nanowires to a textured BaTiO_3 film at temperatures below 160 °C. The microstructure and thickness of the fabricated BaTiO_3 films were characterized by scanning electron microscopy, and the crystal structure and degree of orientation were evaluated by x-ray diffraction patterns using the Lotgering method. It is shown that the thickness of the BaTiO_3 film can be controlled by the length of TiO_2 nanowire array template, and the degree of orientation of the textured BaTiO_3 films is highly dependent on the film thickness; the crystallographic orientation has been measured to reach up to 87%. The relative dielectric constant (ε_r = 1300) and ferroelectric properties (P_r = 2.7 μC cm~(-2), E_c = 4.0 kV mm ~(-1)) of the textured BaTiO_3 films were also characterized to demonstrate their potential application in sensors, random access memory, and micro-electromechanical systems.