Materials Science & Engineering, Lehigh University
Nanocharacterization of Materials Using the Latest Aberration-corrected STEM
Location: EBI Room 1011
Friday, March 15th 2013 - 11:00 am
Chemical analysis at atomic-level spatial resolution with single-atom detection sensitivity is one of the ultimate goals in materials characterization. Such atomic-level materials characterization would be feasible 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 by aberration-correction. 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 , 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 advanced statistical data processing such as multivariate statistical analysis . In this presentation, the latest attempts to obtain atomic-level elemental distributions by EELS and XEDS approaches will be presented.