Insight into long-period pattern by depth sectioning using aberration-corrected scanning transmission electron microscope

Chenzhi Song; Jianlin Wang; Jianping Sun; Yu Liu; Pan Chen; Xiaomin Li; Hongquan Liu; Binghui Ge; Xuedong Bai

doi:10.1016/j.ultramic.2019.112885

Insight into long-period pattern by depth sectioning using aberration-corrected scanning transmission electron microscope

Ultramicroscopy. 2020 Feb:209:112885. doi: 10.1016/j.ultramic.2019.112885. Epub 2019 Nov 5.

Authors

Chenzhi Song¹, Jianlin Wang², Jianping Sun², Yu Liu², Pan Chen², Xiaomin Li², Hongquan Liu³, Binghui Ge⁴, Xuedong Bai⁵

Affiliations

¹ Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
² Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
³ College of Materials Science and Engineering, Shandong University of Science and Technology, Qingdao 266590, China.
⁴ Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China; Key Laboratory of Structure and Functional Regulation of Hybrid Materials (Anhui University), Ministry of Education, Hefei 230601, China. Electronic address: bhge@ahu.edu.cn.
⁵ Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China; Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China. Electronic address: xdbai@iphy.ac.cn.

PMID: 31722280
DOI: 10.1016/j.ultramic.2019.112885

Abstract

Long-period patterns (LPPs) are widely observed by transmission electron microscopy (TEM) in the study of nanoscale materials. Identifying the origin of LPPs is of significant importance when interpreting TEM images, and for an in-depth understanding of material characteristics. However, the two most common LPP categories, modulated structure and moiré patterns, are not easily differentiated by conventional TEM (CTEM). In this work, an LPP was observed in Cu_2-xSe nanoplates by CTEM. And then the depth sectioning with an aberration-corrected scanning transmission electron microscope (AC STEM) has been performed to determine the LPP type. Two misorientated layers were recognized from the depth-series of atomic resolution images of an LPP region, confirming the LPP is a moiré pattern caused by two twisted stacked crystal flakes which commonly exists in nanosized materials. This depth sectioning method is generally applicable for structural characterization of layered systems, and is a powerful approach for the in-situ structural probe of nanomaterials. It is promising to be extended to fast three-dimensional (3D) reconstruction.

Keywords: Cu(2-x)Se; Depth sectioning; Long-period pattern; Moiré pattern; Scanning transmission electron microscopy; Structural characterization.