用200kV电子显微镜分辨Li1-xNbO2中的Nb和O原子  

Distinguishing Nb and O atoms in lithium-niobium oxide with a 200 kV electron microscope

作　　者：王玉梅[1] 李方华[1] 王蓉[2] 车广灿[1] 

机构地区：[1]北京凝聚态物理国家实验室,中国科学院物理研究所,北京100080 [2]北京科技大学材料物理系,北京100083

出　　处：《电子显微学报》2008年第3期173-178,共6页Journal of Chinese Electron Microscopy Society

基　　金：国家自然科学基金资助项目(No.1047412,No.50672124);科技部973项目(No.2006CB601001)~~

摘　　要：在远离Scherzer聚焦条件下,用200 kV的高分辨电子显微镜拍摄了Li1-xNbO2(x≈0.7)高分辨像,再借助像解卷处理使之恢复为直接反映晶体投影结构的解卷像。在不同晶体厚度的解卷像上均能清楚地分辨间距为0.153nm的Nb和O原子柱,看不见Li原子。Nb和O原子的衬度随厚度变化的规律符合赝弱相位物体近似像衬理论。从像模拟得知,即使原始像的离焦量接近Scherzer聚焦条件,解卷处理也同样有助于提高像的质量,并分辨开单个的O原子柱。An image of Li1-xNbO2 （x ≈ 0.7） taken far from the Scherzer focus condition with a 200 kV electron microscope has been tranaformed into the structure image by performing the image deconvolution. The atomic columns of Nb and O at a distance of O. 153 nm are resolved clearly in the deconvoluted images for different crystal thickness, while those of Li atoms are invisible. The image contrast variation for Nb and O atoms with the crystal thickness is consistent with the prediction given by the theory of pseudo-weak-phase object approximation. Besides, the image simulation shows that even when the image defocus is close to the Scherzer focus, the image processing via deconvolution is beneficial to improve the image quality and is necessary to reveal the O atoms individually.

关 键 词：高分辨电子显微像 像解卷 赝弱相位物体近似理论 Li1-xNbO2 

分 类 号：O469[理学—凝聚态物理]