Facile on-demand oriented growth of perovskite oxide thin films: applications of Dion–Jacobson phase as seed layer

Abstract

We investigated a new fabrication process for high-quality, uniaxial-oriented grown Dion–Jacobson perovskite (DJP) RbLaNb₂O₇ thin films by means of excimer laser assisted metal organic deposition. Oriented crystal growth occurred only by excimer laser irradiation in air at 400 °C after a deposition of metal–organic solution and preheating at 400 °C. The obtained RbLaNb₂O₇ thin film showed perfect (010)-oriented growth on borosilicate glass substrates, and the film surface had atomically flat terraces. We confirmed that the obtained DJP RbLaNb₂O₇ thin films functioned very well as a seed layer for the fabrication of various perovskite oxide thin films with high orientation quality. An oriented grown LaNiO₃ thin film fabricated on the DJP seed layer and prepared at 400 °C exhibited low electrical resistivity at room temperature. Moreover, we demonstrated the utility of our methodology for on-demand fabrication by combining our method with an inkjet printing technique to pattern LaNiO₃ thin films with a line shape, which also were successfully grown with uniaxial orientation on the DJP seed layer. A ferroelectric Na_0.5K_0.5NbO₃ perovskite film was heteroepitaxially grown on the uniaxial-oriented grains of the LaNiO₃/RbLaNb₂O₇ thin film, and this oriented film exhibited a higher dielectric constant than that of a film fabricated without the DJP seed layer. Thus, we demonstrated facile, oriented crystal growth enabled by the uniaxial-oriented DJP seed layer.