钛酸钡/钛酸锶多层薄膜微观结构及其生长机制研究  

The study of microstructure and growth mode of the multilayer films in BaTiO_3/SrTiO_3

作　　者：何俊明[1] 周艺[1] 丁莹[2] 李骏驰[2] 陈江华[2] 刘明[3] 马春蕊[3] 陈充林[3] 

机构地区：[1]长沙理工大学化学与生物工程学院,长沙湖南410004 [2]湖南大学高分辨电镜中心,长沙湖南410082 [3]德克萨斯大学物理系,美国德克萨斯圣安东尼奥77249

出　　处：《电子显微学报》2012年第6期486-492,共7页Journal of Chinese Electron Microscopy Society

基　　金：国家自然科学基金资助项目(No.21171027)

摘　　要：采用脉冲激光沉积方法,在氧化镁(MgO)单晶的(001)晶面上制备出钛酸钡(BaTiO3)/钛酸锶(SrTiO3)多层薄膜。利用高分辨透射电子显微镜(HRTEM)以及高角环形暗场(HAADF)像对其微观结构进行了详细研究,并探讨了多层膜的生长机制。结果表明:(1)在基体/薄膜界面附近存在周期性的失配位错,伯格斯矢量为a2<110>;(2)界面附近存在界面层(过渡层),层内可能存在局部畴域;(3)薄膜内存在位移矢量为12<110>的富Ti型和富Ba型两种层错;(4)薄膜生长过程中,由于弛豫产生的应变分布不均使得沉积原子倾向于在低应力处成核,最终多层膜显示柱状结构。BaTiO3（BTO）/SrTiO3（STO） superlattice thin films were grown on（001） MgO substrates using pulsed laser deposition.The microstructure and interfacial defects of the film were studied by means of high resolution transmission electron microscopy（HRTEM） and High Angle Annular Dark Field STEM（HAADF-STEM）.Based on the observation results,a growth mechanism of the film was proposed.It is shown that（Ⅰ） periodical misfit dislocations with a Burgers vector of a 2110 exist near the interface;（Ⅱ） a very thin transitional interfacial layer appears at the film/substrate interface,in which local domains seem existed;（Ⅲ） two types of stacking faults exist in the film：Ti-rich and Ba-rich,and both of them have a Burgers vector of a 2110;（Ⅳ） during the growth,ununiform internal stresses resulted from relaxation make the BTO/STO superlattice thin film to form column structures.

关 键 词：多层薄膜 柱状生长 微观结构 高分辨透射电子显微镜 

分 类 号：TB383.2[一般工业技术—材料科学与工程]