Modulating multiple leakage current mechanisms in the [LaNiO3/Ba0.67Sr0.33TiO3]3 multilayer heterostructure thin films via dielectrics/electrode interface modifications

Ferroelectric (FE) multilayer heterostructure films have attracted significant attention due to their superior dielectric performance, which shows increasing opportunities in the application of energy storage capacitors or high-capacitance density systems. However, the leakage current density in FE multilayer heterostructure thin films is closely linked to the thickness of each single FE layer and the number of hetero-structure interfaces. In Pt/[LaNiO3/Ba0.67Sr0.33TiO3]3 (Pt/[LNO/BST]3) multilayer thin films, the dominant leakage current mechanism is Poole–Frenkel (PF) emission at room temperature. The space charge limited current (SCLC) and the co-dominated leakage current mechanism from the PF and Schottky (SC) emissions were observed under higher operating temperatures. After inserting an ultrathin SrTiO3 (STO) layer between the Pt/[LNO/BST]3 multilayer thin films and the top Au electrode, the SCLC region was replaced by an Ohmic region, and the SC emission was not detected in the temperature range of 288–368 K. Moreover, the calculated zero-field energy barriers ϕPF of PF emission are higher than the prepared multilayer thin films without the STO layer. Consequently, the leakage current density of Pt/[LNO/BST]3 thin films showed a significant decrease.