球差校正透射电镜技术探究SrTiO_(3)/SrTiO_(3)同质薄膜导电起源  

Exploring the conductive origin of SrTiO_(3)/SrTiO_(3)homogeneous films by spherical aberration-corrected transmission electron microscopy

作　　者：宋海利 黄荣[2] SONG Haili;HUANG Rong(School of Chemistry,Sun Yat-sen University/Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education,Guangzhou 510006,China;School of Physics and Electronic Science,East China Normal University/Key Laboratory of Polar Materials and Devices,Ministry of Education,Shanghai 200062,China)

机构地区：[1]中山大学化学学院/生物无机与合成化学教育部重点实验室,广东广州510006 [2]华东师范大学物理与电子科学学院/极化材料与器件教育部重点实验室,上海200062

出　　处：《中山大学学报（自然科学版）（中英文）》2023年第5期101-106,共6页Acta Scientiarum Naturalium Universitatis Sunyatseni

基　　金：广东省基础与应用基础研究基金(2020A1515110178)。

摘　　要：通过脉冲激光沉积方法沿着SrTiO_(3)衬底(001)方向生长了SrTiO_(3)/SrTiO_(3)(001)同质外延薄膜,薄膜退火前为导电状态,在氧气气氛中退火后变为绝缘态。运用环形高角暗场像、环形明场像和能量损失谱等多种先进的球差校正透射电镜技术,从原子尺度分析薄膜表面和界面处的原子占位、电子结构以及氧空位等。研究发现,退火前薄膜表面存在TiO_(x)(1<x<2)重构层,退火后重构层仍然存在,但Ti的价态有所升高。同时,通过原子分辨率的能量损失谱分析对比了退火前后Ti和O的价态变化,发现:退火前薄膜表面和界面附近存在氧空位,薄膜表面的氧空位更多,退火后氧空位消失。因此,对于SrTiO_(3)/SrTiO_(3)同质薄膜来说,薄膜导电的起源主要为薄膜表面和界面附近氧空位的共同作用。A SrTiO_(3)/SrTiO_(3)homogeneous epitaxial film was grown along the SrTiO_(3)substrate(001)by PLD method.The film was conductive before annealing,and became insulating states after annealing.A variety of advanced spherical aberration-corrected transmission microscopy techniques like annular high-angle darkfield image,annular brightfield image and atomic-resolution energy loss spectroscope(EELS)was used to explore the atomic occupancy,electronic structure and oxygen vacancies in the film.A TiO_(x)(1<x<2)reconstruction layer was found on the surface of the film.And the valence state of Ti in the reconstruction layer increases slightly after annealing.According to EELS analysis,oxygen vacancies existed in the whole film including the surface and interface before annealing,and disappeared after annealing.Therefore,for non-polar films SrTiO_(3)/SrTiO_(3),oxygen vacancies near the film surface and interface maybe the origin of electrical conduction.

关 键 词：钙钛矿氧化物 球差校正透射电镜 电子能量损失谱 氧空位 

分 类 号：O73[理学—晶体学] O766