钙掺杂锆钛酸钡薄膜的储能特性及击穿强度增强

Calcium (Ca 2+ )-doped BZT thin films, Ba 1-x Ca x Zr 0.2 Ti 0.8 O 3 ( x = 0, 0.05, 0.1, 0.15 and 0.2), were synthesized on the Pt/Ti/SiO 2 /Si substrates via sol–gel spin-coating techniques for pulse capacitor applications. The microstructures, ferroelectric properties and energy storage performance of Ba 1-x Ca x Zr 0.2 Ti 0.8 O 3 thin films were characterized while adjusting the Ca 2+ concentration. It is found that the Ca 2+ -doped BZT thin films exhibit single-phase perovskite structure. On increasing the Ca 2+ concentration, the cell volume and tolerance factor declined due to the replacement of Ca 2+ ions for the A-site ions in the BZT lattice. The average grain size and root-mean-square (RMS) roughness of Ba 1-x Ca x Zr 0.2 Ti 0.8 O 3 thin films with dense and uniform microstructure is refined to 44 nm and 1.55nm, respectively, with Ca 2+ increasing up to x = 0.15. While lowering the leakage current density after Ca 2+ modification, the breakdown field strength of Ca 2+ -doped BZT thin films is improved significantly approaching 4210 kV/cm at x = 0.15. Because of the enlarged polarization difference ( P m – P r ), the nano grain Ba 0.85 Ca 0.15 Zr 0.2 Ti 0.8 O 3 thin film possesses an elevated energy storage density of 33.1 J/cm 3 and an acceptable energy storage efficiency of 62.1% at the ultrahigh breakdown field. The Ca-doped BZT films also have remarkable cycle reliability showing a significant potential for capacitor applications.