Enhanced energy storage property and dielectric tunability of Na_0.5Bi_0.5(Ti,W,Ni)O₃ thin film on Bi(Fe,Mn)O₃ buffered LaNiO₃(100)/Si substrate

Na_0.5Bi_0.5(Ti,W,Ni)O₃ (NBTWN) thin films were fabricated on the pure and Bi(Fe,Mn)O₃ buffered Pt/TiO₂/SiO₂/Si and LaNiO₃(100)/Si substrates by chemical solution deposition, respectively. The crystallization, surface morphology, and electrical properties of the four films are mainly investigated. The films, which are grown on the Pt/TiO₂/SiO₂/Si substrates, exhibit similar polycrystalline structure. Whereas for films deposited on the LaNiO₃ (100)/Si substrates, strong (l00) orientations are observed. Compared with the NBTWN film on pure Pt/TiO₂/SiO₂/Si, the introduction of Bi(Fe,Mn)O₃ buffer layer and LaNiO₃ oxide electrode can promote the grain growth of the NBTWN resulting in larger grain size. Large remanent polarization and breakdown strength can be observed in films with Bi(Fe,Mn)O₃ buffer layers. Furthermore, the combination of low leakage current and good energy storage capacity, together with high dielectric tunability is achieved in NBTWN/Bi(Fe,Mn)O₃/LaNiO₃(100)/Si heterostructure. The enhancement in electrical properties may be attributed to the preferred crystalline orientation and optimized grain size depending on both the buffer layer and the electrode that are used.