Effect of zinc and magnesium ion doping on leakage current behavior of Ba0.6Sr0.4TiO3 thin film

We report an in-depth analysis of the carrier conduction mechanisms in multilayer doped Ba0.6Sr0.4TiO3 films, which offers a significant new message for reducing the leakage current. First, Ba0.6Sr0.4TiO3 (BST) sol, Ba0.6Sr0.4Ti0.99Zn0.01O3 (ZBST) sol, and Ba0.6Sr0.4Ti0.99Mg0.01O3 (MBST) sol were prepared using the sol-gel method. Then, BST, ZBST, MBST, and binary alternating-structure Ba0.6Sr0.4Ti0.99Zn0.01O3/Ba0.6Sr0.4Ti0.99Mg0.01O3/Ba0.6Sr0.4Ti0.99Zn0.01O3 (ZMZ) thin films were designed and prepared. The effects of single-component doping and binary alternating doping on the interface barrier height and trap barrier height of the Ba0.6Sr0.4TiO3 thin films were studied. The results showed that the interface barrier height of ZMZ thin films is 0.55 eV, and the interface barrier height of BST thin films is 0.53 eV. Compared with the ZBST and MBST thin films, the change in the interface barrier height of the ZMZ film was not obvious. The trap barrier height of the ZMZ thin film is 0.17 eV, and the trap potential barrier height of the BST thin film is 0.12 eV. The trap barrier heights of ZBST thin films and MBST thin films are 0.15 eV and 0.16 eV, respectively. The enhancement of the trap barrier height may be related to the weakening of the trap and donor effects caused by oxygen vacancy defects. The energy band diagram shows the relationship between the oxygen vacancy defects, interface barrier height, and trap barrier height.