Effects of LaNiO₃ buffer layers on preferential orientation growth and properties of PbTiO₃ thin films

(1 0 0)- and (1 0 1)-oriented PbTiO₃ (PT) thin films on conductive LaNiO₃ (LNO)-coated Si(1 1 1) substrates were prepared by a metal-organic decomposition method. It is found that the crystallization states of LNO thin films used as buffer layers have significantly effects on preferential orientation of PT thin films. PT thin films with (1 0 0) orientation could be obtained not only on the crystalline LNO (1 0 0) film, but also on the amorphous LNO thin film. The highly (1 0 0)-oriented PT films show high dielectric constant of 189.4 on LNO (1 0 0) films and 183.1 on amorphous LNO films. The PT capacitors fabricated on the LNO buffer layers display good P-E hysteresis loops. The remnant polarization (P_r) and coercive field (E_c) of PT films on amorphous, (1 0 0)- and (1 1 0)-oriented LNO films are 9.35 μC/cm² and 162.8 kV/cm, 10.03 μC/cm² and 163.3 kV/cm, 11.23 μC/cm² and 166.2 kV/cm, respectively.