铁电极化诱导的PbTiO3薄膜的取向聚集生长和晶粒尺寸调控

用溶胶凝胶法制备了PbTiO₃薄膜。将含量为0.2%、0.5%和0.8%(摩尔比)的钙钛矿铁电PbTiO₃纳米片加入溶胶体系中，利用纳米片的自发极化调控薄膜的生长。结果表明，纳米片的加入显著影响了薄膜的生长过程和结晶学取向，可制备出(100)高度取向的PbTiO₃薄膜；改变纳米片的浓度，可将薄膜晶粒尺寸由100 nm调控到2 μm。扫描电子显微镜(SEM)、透射电子显微镜(TEM)观测和原位X射线衍射(in-situ XRD)的结果表明，固态薄膜中的晶粒表现出类液相的取向聚集生长特征。其原因可能是，铁电纳米片极化表面的静电力诱导小晶粒的吸附和取向排列，调控了薄膜的(100)取向和晶粒尺寸。

Ferroelectric Polarization Induced Oriented Attachment Growth of PbTiO3 Films and Grain Size Control

PbTiO₃ (PTO) ferroelectric thin films were synthesized by a sol-gel process, where different concentration (0.2%, 0.5%, 0.8%, mole ratio) of PbTiO₃ nanoplates with large spontaneous polarity were introduced to the sol system to manipulate the growth and microstructures of PbTiO₃ films. The products were then characterized by means of X-ray diffractometer(XRD), scanning electron microscope (SEM), transmission electron microscope (TEM). The effect of PTO nanoplates on the growth mechanism of PTO films was investigated by in-situ XRD. It was found that nanoplates dramatically affected the growth process and crystallographic orientation of PbTiO₃ films, giving rise to a preferred orientation of (100) in PbTiO₃ films. In addition, an effective control of grain size of PbTiO₃ films ranging from 100 nm to 2 μm has been realized by altering the concentration of nanoplates. According to results of SEM, TEM and in-situ XRD analysis, the grains in solid-state films exhibited the growth characteristics of orientation related gathering of gains, similar to that in liquid phase. This growth behavior can be attributed to the strong electrostatic force originated from polar surfaces of nanoplates, which induced the adsorption and oriented alignment of small grains, accounting for the orientation and grain size evolution.