Effects of seed layer and crystallization process on crystal orientation and properties of NKBT thin films

Abstract

Lead-free (Na 0.85 K 0.15 ) 0.5 Bi 0.5 TiO 3 (NKBT) piezoelectric thin films were fabricated via an aqueous solgel method on Pt(111)/Ti/SiO 2 /Si substrates. The thin films, with and without Pb 0.8 La 0.1 Ca 0.1 Ti 0.975 O 3 seed layer, were obtained by single-crystallization and multiple-crystallization processes. The NKBT thin films derived by multiple-crystallization process exhibited better single perovskite structure, and the films with PLCT seed layers were well crystallized with high (100) orientation. The effects that seed layer and different crystallization processes have on crystal orientation and electrical properties can be attributed to extrinsic and intrinsic contributions, and their different mechanism and ranges of improvement in the dielectricity and piezoelectricity are observed and discussed. The NKBT thin films that prepared by multiple crystallization with PLCT seed layer had the best electric property with e r of 598, tand of 0.08, and d 33 of 136 pm/V. Graphical Abstract

Enhanced ferroelectric properties in BiAlO3 modified lead‐free Mn‐doped Bi0.5(Na0.8K0.2)0.5TiO3 thin films

“…15,16 Amongst lead-free ferroelectric materials, sodium bismuth titanate (Bi 0.5 Na 0.5 TiO 3 ) is considered one of the most promising materials due to its strong ferroelectricity (P r = 38 µC/cm 2 ) at room temperature and high piezoelectric performance, especially the Bi 0.5 K 0.5 TiO 3 modified morphotropic phase boundary (MPB) solid solution 0.8Bi 0.5 Na 0.5 TiO 3 −0.2Bi 0.5 K 0.5 TiO 3 . 17,18 To improve energy storage, most researchers have used ion doping to enhance the properties of the films. Chen et al investigated the (1-x)Bi 0.5 (Na 0.8 K 0.2 ) 0.5 TiO 3 -xSrZrO 3 thin films and found that the films had excellent performance (W rec = 34.69 J/cm 3 , η = 59.32%) at x = 0.15.…”