The TEAM0.5 microscope: Single atom detection across the Periodic Table of Element – Niels Bohr Institute - University of Copenhagen

Niels Bohr Institute > Calendar > 2008 > Seminar by Christian K...

The TEAM0.5 microscope: Single atom detection across the Periodic Table of Element

The Transmission Electron Aberration-corrected Microscope (TEAM) project was initiated as a collaborative effort to redesign the electron microscope around aberration corrected optics [1]. The Project aims at extending the spatial resolution to 50 pm and at improving contrast, stability, sensitivity, brightness and energy resolution. A prototype (TEAM0.5) of such an instrument became recently available [2]. One outstanding goal of the ongoing efforts in electron microscopy is the realization of electron tomography with atomic resolution. In this context it is of essence characterizing achievable signal-to-noise ratios for the detection of single atoms and controlling radiation damage on a single atom level. In this contribution it is shown that extraordinary signal-to-noise levels can be obtained in single lattice images that even allow for the detection of individual carbon atoms well above noise [3]. As a result it becomes possible to study atom clusters on a single atom level and to control radiation damage atom by atom. We find that radiation damage affects weakly bound atoms at crystal surfaces first and show that single carbon, germanium and gold atoms can be kept in place or be registered if removed in experiments utilizing acceleration voltages between 80 kV and 300 kV.In particular it is now possible to simultaneously image the presence of a heavy atom and a light atom, which is of interest for investigating catalytical processes.

[1] The TEAM project is supported by the Department of Energy, Office of Science, Basic Energy Sciences. NCEM is supported by the Department of Energy under Contract # DE-AC02-05CH11231.
[2] C. Kisielowski, B. Freitag, M. Bischoff, H. van Lin, S. Lazar, G. Knippels, P. Tiemeijer, M. van der Stam, S. von Harrach, M. Stekelenburg, M. Haider, S. Uhlemann, H. Muller, P. Hartel, B. Kabius, D. Miller, I. Petrov, E. A. Olson, T. Donchev, E. A. Kenik, A. Lupini, J. Bentley, S. Pennycook, I.M. Anderson, A. M. Minor, A. K. Schmid, T. Duden, V. Radmilovic, Q. Ramasse, M. Watanabe, R. Erni, E. A. Stach, P. Denes, and U. Dahmen. Detection of single atoms and buried defects in three dimensions by aberration-corrected electron microscopy with 0.5 angstrom information limit. In review, 2008.
[3] J. C. Meyer, C. Kisielowski, R. Erni, M.D. Rossell, A. Zettl, Direct imaging of lattice atoms and topological defects in graphene membranes, NanoLetters, in press, 2008