中文摘要：

对硅衬底生长的Bi4Ti3O12和Bi3.25La0.75Ti3O12薄膜样品测量了慢正电子多普勒展宽谱,得到了S参数随正电子注入能量的变化。通过对S参数和W参数的分析,讨论了这类材料中的捕获态特征和结构特点,结果表明,薄膜与硅衬底界面的缺陷为空位-氧复合体,La的掺杂有助于阻止空位-氧复合体向界面的扩散。

英文摘要：

A series Doppler broadening spectra of Bi4Ti3O12 and Bi3.25La0.75Ti3O12 ferroelectric films deposited on silicon substrate were measured by means of variable-energy positron beam,the positron implantation energy dependence of shape parameter S were performed.The S（E） and W（E） data are analyzed dy plotting them in the S-W plane,the positron trapping states related to the structure of the samples are discussed.The results indicate that for the both samples the defects on the interface region between ferroelectric film and Si substrate are of multivacancy-multioxygen complexes（VxOy） type.It also implies the doping of lanthanum is helpful to increase the diffusion resistance of the defects.