Reduced leakage current, enhanced energy storage and dielectric properties in (Ce,Mn)-codoped Ba0.6Sr0.4TiO3 thin film

Abstract

Ba0.6Sr0.4TiO3, Ce-doped Ba0.6Sr0.4TiO3, Mn-doped Ba0.6Sr0.4TiO3, (Ce,Mn) co-doped Ba0.6Sr0.4TiO3 (abbreviated as BST, BSTCe, BSTMn, BSTCeMn) thin films were deposited on LaNiO3(LNO)/Si substrates. The effects of ion doping on the microstructure and electrical properties of BST-based thin film have been researched and discussed. The X-ray diffraction pattern shows that each sample has pure perovskite phase structure with high (l00) peaks. The microstructure of each film is quite dense with uniform size. Compared with pure BST, improved insulating properties can be found in ion-doped BST thin films. For all the films, Ohmic conduction, space charge limited conduction and interface-limited Fowler-Nordheim tunneling should be the main conduction mechanisms within different electric field regions. For the case of BSTCeMn thin film, it possesses enhanced energy storage performance with a recoverable energy storage density (18.01 J/cm3) and a energy storage efficiency (75.1%) under 2000 kV/cm. This can be closely related to the small remanent polarization value (Pr= 1.89 μC/cm2), large maximum polarization value (Pmax= 28.08 μC/cm2) as well as big maximum electric field (2000 kV/cm). Also, it exhibits a large dielectric constant of 405 and a small dissipation factor of 0.075 at 500 kHz.