200919 Advances in Electron Energy Loss Spectroscopy: A Synchrotron in Electron Microscope

Title:
Advances in Electron Energy Loss Spectroscopy: A Synchrotron in Electron Microscope

Speaker:
廖堃硯 (Kun-Yen Liao), PhD student, The University of Tokyo

Time:
09/19 (Sat.) 7 pm PDT, 8 pm MDT, 9 pm CDT, 10 pm EDT
09/20 (Sun.) 10 am Taiwan

Keywords:
Materials Science, Electron Microscopy, Materials Characterization, Electron Microscopy, STEM-EELS, Atomic Spectroscopy

Abstract:

Electron energy loss spectroscopy (EELS) in scanning transmission electron microscope (STEM) is a powerful tool for high-resolution chemical analysis. Various information can be obtained from EELS such as valence states and local coordination. Using small incident electron probe, STEM-EELS has the advantage to be recorded in atomic resolution, serving as a complementary tool for X-ray and neutron spectroscopy. In recent years, improvement of electron monochromator has enable nm-scale detection of plasmon and phonon excitation in nanomaterials and interfaces. These advantages have made STEM-EELS a synchrotron-like facility in the microscope.

In the presentation, I will start with the introduction and recent development of modern Cs-corrected electron microscope. Afterward, I will focus on the principle of STEM-EELS working for different energy range. Several examples, including structural, plasmonic and phonon studies, will be introduced. Finally, theoretical calculation of EELS using density functional theory (DFT) and neural network will be shortly explained.