Ba_xSr_(1-x)TiO_3 thin films prepared by OTS monomolecular film reverse induction and liquid phase self-assembly method

摘要

Octadecyl-trichlorosilane self-assembled monolayers (OTS-SAMs) were prepared on the ITO glass substrate surface by self-assembled monomolecular film technique and Ba_xSr_(1-x)TiO_3 thin film was prepared by the reverse induction and adsorption on the functionalized substrate surface. The morphologies of OTS-SAMs before and after UV-light irradiation, the variation of the contact angles, and the microstructure and electrical property of Ba_xSr_(1-x)TiO_3 thin film were investigated. The results show that after UV-light irradiation, the hydrophilic film of OTS-SAMs with the thickness of 1 nm and the contact angle of 5° can be used to prepare the homogeneous Ba_xSr_(1-x)TiO_3 thin film by the reverse induction method. As the increase of Ba content, the diffraction peaks corresponding to SrTiO_3 crystal plane is shifted to small angles. The grains of the thin film are decreased as the increase of Ba doping content. When Sr/Ba is between 9/1 and 8/2, the dielectric constant of Ba_xSr_(1-x)TiO_3 thin film is higher while the dielectric loss is smaller. At 10 kHz, the dielectric constant of Ba_(0.2)Sr_(0.8)TiO_3 thin film is 880 and the dielectric loss is 0.04. The remnant polarization of Ba_xSr_(1-x)TiO_3 thin film prepared by the reverse induction and adsorption and liquid phase self-assembly method is 0.64 μC/cm~2 and the coer-civity is 13.84 kV/cm.