Single atom and vibrational spectroscopies in the electron microscope

CIC nanoGUNE Seminars

Speaker

Ondrej L. Krivanek (Nion R&D, and Department of Physics, Arizona State University, Tempe, Arizona, USA)

When

2017/09/29
13:00

Place

nanoGUNE seminar room, Tolosa Hiribidea 76, Donostia - San Sebastian

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Modern-day electron microscopes are able to form intense electron probes as small as 0.5-1 Å in diameter, or slightly larger probes that have an energy spread <10 meV. This allows them to analyze single atoms spectroscopically (by electron energy loss spectroscopy (EELS) or energy-dispersive X-ray spectroscopy (EDXS)), and to probe the chemical composition of organic materials while avoiding radiation damage. Nion has pioneered many of these advances, by developing STEM aberration correction technology (in the 1990s), and then a new electron microscope that is able to acquire images and spectra from single atoms (in 2008, with continuing developments since), and which may make atom-by-atom materials engineering a practical reality. We have also introduced a new type of a monochromator, which allows materials to be probed by vibrational EELS carried out with better than 10 meV energy resolution and about 1 nm spatial resolution, as well as damage-free vibrational analysis in an “aloof” mode. My talk will review these advances and illustrate them with practical examples. Ondrej L. Krivanek, FRS, is the President of Nion Co., and Affiliate Professor at Arizona State University. He is well known for pioneering new techniques of structure research and for developing new instruments, from simple-to-operate serial and parallel detection electron energy-loss spectrometers (EELS) and imaging filters to the first working aberration corrector for a scanning transmission electron microscope (STEM). In 1997 Ondrej and Niklas Dellby founded the Nion Company, which introduced instruments that have established many important benchmarks, including the first-ever sub-Å electron probe, single-atom EELS and EDXS, and vibrational spectroscopy in the electron microscope. Ondrej is an Honorary Fellow of Robinson College Cambridge and of the Royal Microscopical Society, and Fellow of American Physical Society, the British Institute of Physics, the Microscopy Society of America and the Royal Society. **Host** : Javier Aizpurua