La、Nb掺杂对Bi_4Ti_3O_(12)薄膜介电性能和C-V特性的影响

Effect of La and Nb Doping on Dielectric Properties and C-V Characteristics of Bi_4Ti_3O_(12) Thin Films

采用溶胶-凝胶工艺制备了Bi4-xLaxTi3O12和Bi4Ti3-yNbyO12铁电薄膜,研究了La、Nb掺杂对薄膜介电性能和C-V特性的影响。研究表明,在x<0.75、y<0.06范围内,随La、Nb掺杂量的增加,Bi4-xLaxTi3O12和Bi4Ti3-yNbyO12薄膜的介电常数和C-V特性曲线回滞窗口增大,介电损耗和漏电流密度减小。x>0.5时,Bi4-xLaxTi3O12薄膜可获得大于1.8V的C-V回滞窗口,且经1010极化开关后其回滞窗口的减小未超过6%;而Nb掺杂对增大Bi4Ti3-yNbyO12薄膜C-V回滞窗口的作用更加明显,但经1010极化开关后,其回滞窗口的减小较为明显,并出现一定平移。

Bi4-xLaxTi3O12 and Bi4Ti3-yNbyO12 ferroelectric thin films were fabricated by sol-gel technique. The effect of La and Nb doping on the dielectric properties and C-V characteristics of Bi4 -xLaxTi3O12 and Bi4Ti3 -yNbyO12 thin films were investigated. As the La （ x 0. 75） or Nb （ y 0. 06） increasing,the C-V hysteresis window and the dielectric constant of Bi4 -x LaxTi3O12 and Bi4Ti3 -y NbyO12 thin films increase,meanwhile the tan δ and leak current density decrease. The C-V hysteresis window of Bi4 -xLaxTi3O12 thin films is larger than 1. 8 V when x 0. 5 and decrease less than 6% after 1010 switching. Doping of Nb have great influence on C-V hysteresis window of Bi4Ti3 -yNbyO12 thin films,but smaller C-V hysteresis window with a shift can be observed after 1010 switching.