Atomic-Resolution Elemental Mapping by EELS and XEDS in Aberration Corrected STEM

Recent improvements in aberration correction have brought tremendous advantages not only in high resolution imaging but also in high resolution analysis by electron energy-loss spectrometry (EELS) and X-ray energy-dispersive spectrometry (XEDS) in scanning transmission electron microscopy (STEM). Once the incident probe formation is optimized, atomic-resolution analysis can be performed by acquiring sufficient enough signals for appropriate chemical analysis while maintaining fine probe sizes. In addition,more sophisticated approaches of data acquisition and analysis, such as spectrum imaging (SI) and multivariate statistical analysis (MSA), are essential for atomic-resolution chemical analysis. In fact, it is possible to obtain atomic-resolution chemical images of materials since both the spatial resolution and analytical sensitivity are improved tremendously in combination of the aberration correction instrument with the advanced acquisition and analysis techniques. In this manuscript, the incident probe formation,data acquisition and data analysis are reviewed for atomic-resolution chemical analysis by EELS and XEDS in aberration-corrected instruments. Then, several applications of atomic-resolution chemical images obtained by the recently developed JEM-ARM200F aberration-corrected microscope are shown to address future trends in chemical analysis of materials.