2011.09.29

Auditorium, 1st floor, Eng. Bldg. #9, Hongo Campus

Dr. Masashi Watanabe
       Associate Professor of Materials Science and
       Engineering, Lehigh University, USA

Tile：Atomic-resolution Spectrometry using Aberration-corrected
STEMs in Combination with Multivariate Statistical Analysis

Abstract：
Chemical analysis at atomic-level with single-atom detection sensitivity is one of the ultimate goals in materials characterization. Such atomic-level characterization would be possible by electron energy-loss spectrometry (EELS) and X-ray energy dispersive spectrometry (XEDS) in the latest aberration-corrected scanning transmission electron microscopes (STEMs) because more probe current can be added into the incident probe refined by aberrationcorrection. Especially for EELS analysis, sufficient amounts of core-loss signals can be generated within a short acquisition time by higher current probes, and hence atomic-resolution EELS mapping has already been applied [e.g., 1-3]. For XEDS analysis, spatial resolution reaches ~ 0.4 nm [4], which implies atomic-level analysis is feasible, in aberration- corrected STEM. However, atomic-level chemical analysis is even more challenging in the XEDS approach since detection of X-ray signals is more limited than that in EELS (~100 times difference). The limited signals can be improved by applying spectrum-imaging (which records a full spectrum at individual pixels) in combination with multivariate statistical analysis [5]. In this presentation, the latest attempts to obtain atomic-level elemental distributions by EELS and XEDS approaches will be presented.

Schedule： 15:00-17:00, September 29 (Thursday), 2011
Place：Auditorium, 1st floor, Eng. Bldg. #9, Hongo Campus

Attached file： The_82th_open_seminar.pdf