Electrophoretic deposition of Ca2Nb3O10− nanosheets synthesized by soft-chemical exfoliation
Ca2Nb3O10− (CNO−) nanosheets exfoliated from a KCa2Nb3O10 ceramic were deposited on a Pt/Ti/SiO2/Si substrate at room temperature (RT) using the electrophoresis method, and subsequently annealed at various temperatures to remove organic defects. The inter-planar distance of the (001) plane of the CNO film deposited at RT was large (1.68 nm). This distance gradually decreased to 1.44 nm when the annealing temperature was increased to 600 °C due to the removal of organic defects. For CNO films annealed at temperatures higher than 600 °C, a CaNb2O6 secondary phase was formed, indicating that annealing should be conducted at 600 °C to obtain a homogeneous CNO film. Moreover, the CNO film annealed at 600 °C showed a large εr value of 65 with a low tan δ of 0.01 at 1.0 MHz. This film also exhibited a high breakdown electric field of 0.43 MV cm−1 and a very low leakage current density of 3 × 10−8 A cm−2 at 0.4 MV cm−1.