Electron Tomography: Seeing Atoms in Three Dimensions

Journal Article · Thu Nov 01 04:00:00 EDT 2012 · Nature Materials, 11(11):911-912

DOI:https://doi.org/10.1038/nmat3472· OSTI ID:1054426

Arslan, Ilke; Stach, Eric A

Our eyes - a parallel lens system - have the phenomenal ability to observe and "reconstruct" the three-dimensional world, relaying a 3-D image to our brains. Imaging of the nanoworld is best done with electrons rather than photons because of their lower wavelengths and higher resolution. The advent of aberration-correction has led to transmission electron microscopes with sub-Angstrom resolution that can resolve single atoms. Yet, no matter what detector is used, the resulting images are only two-dimensional projections of three-dimensional objects. Electron tomography is a technique that allows reconstruction of the three-dimensional structure and morphology of nanomaterials from such projections. X-ray tomography has been used in many branches of science for nearly half a century, and in the biological sciences electron tomography has been a powerful tool for understanding ultrastructure. However, for many years crystalline materials posed a challenge to electron tomography because diffraction contrast (a change in intensity in the image at particular crystal orientations) creates artifacts in the 3-D reconstruction. In 2003, with advances in scanning transmission electron microscopy, Midgley and colleagues obtained the first electron tomograms of crystalline materials. Shortly thereafter, Arslan et al. showed that the spatial resolution could be improved to 1 nm in all three spatial dimensions and visualized the formation of faceted 3.5-nm quantum dots embedded in a Si matrix. However, with that work existing reconstruction algorithms appeared to have reached their limit. To attain a resolution of 1 nm, a total of 140 images over ±78 degrees of tilt were needed. Writing in Nature Materials, Goris et al. now report a novel algorithm for 3-D reconstruction of the atomic structure of free-standing Au nanorods, using only four projection images. I.A. acknowledges collaboration with J.D. Roehling, K.J. Batenburg, B.C. Gates and A. Katz for Figure 1, supported in part by the DOE BES DE-SC0005822, and in part by the LDRD program at PNNL. The Pacific Northwest National Laboratory is operated by Battelle under contract DE-AC05-76RL01830.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1054426
• Report Number(s): PNNL-SA-91168
• Journal Information: Nature Materials, 11(11):911-912, Journal Name: Nature Materials, 11(11):911-912
• Country of Publication: United States
• Language: English