退火温度对BiFeO_3薄膜结构与性能的影响

Effect of Annealing Temperature on Structure and Properties of BiFeO_3 Thin Films

采用溶胶-凝胶法在ITO/glass衬底上制备了BiFeO_3薄膜。研究了退火温度对BiFeO_3薄膜样品的晶体结构、显微结构和铁电性能的影响,退火温度分别为450,475,500和525℃。并分析了相关机理。结果表明:当退火温度不高于500℃时,薄膜结晶较好,表面致密平整,随退火温度升高薄膜晶粒逐渐长大,当退火温度为500℃时,剩余极化强度Pr为62μC/cm^2;当退火温度增加到525℃时,薄膜表面晶粒较不均匀且出现了较多气孔,薄膜的铁电性能较差。

BiFeO_3 thin films were prepared on ITO/glass by a sol-gel method and the annealing temperatures were 450, 475, 500 and 525 ℃. The effect of annealing temperature on the crystal structure, microstructure, and ferroelectric properties of BiFeO_3 thin films was studied, and the mechanism was also analyzed. Results show that when the annealing temperatures are not higher than 500 ℃, the crystallinity of the films is good, and the surface is dense and smooth. The grain size gets larger as the annealing temperature increases. The remanent polarization is 62 μC/cm^2 when the annealing temperature is 500 ℃. However, as the annealing temperature increases to 525 ℃,the grain size becomes nonuniform and the ferroelectric property deteriorates.