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Fast Atomic-Scale Elemental Mapping of Crystalline Materials by STEM Energy-Dispersive X-Ray Spectroscopy Achieved with Thin Specimens

Published online by Cambridge University Press:  23 February 2017

Ping Lu ,
Renliang Yuan  and
Jian Min Zuo
Ping Lu*
Affiliation:
Sandia National Laboratories, Albuquerque, NM 87185, USA
Renliang Yuan
Affiliation:
Department of Materials Science and Engineering, University of Illinois at Urbana–Champaign, 1304 W Green St, Urbana, IL 61801, USA
Jian Min Zuo
Affiliation:
Department of Materials Science and Engineering, University of Illinois at Urbana–Champaign, 1304 W Green St, Urbana, IL 61801, USA
*
*Corresponding author: plu@sandia.gov
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Abstract

Elemental mapping at the atomic-scale by scanning transmission electron microscopy (STEM) using energy-dispersive X-ray spectroscopy (EDS) provides a powerful real-space approach to chemical characterization of crystal structures. However, applications of this powerful technique have been limited by inefficient X-ray emission and collection, which require long acquisition times. Recently, using a lattice-vector translation method, we have shown that rapid atomic-scale elemental mapping using STEM-EDS can be achieved. This method provides atomic-scale elemental maps averaged over crystal areas of ~few 10 nm2 with the acquisition time of ~2 s or less. Here we report the details of this method, and, in particular, investigate the experimental conditions necessary for achieving it. It shows, that in addition to usual conditions required for atomic-scale imaging, a thin specimen is essential for the technique to be successful. Phenomenological modeling shows that the localization of X-ray signals to atomic columns is a key reason. The effect of specimen thickness on the signal delocalization is studied by multislice image simulations. The results show that the X-ray localization can be achieved by choosing a thin specimen, and the thickness of less than about 22 nm is preferred for SrTiO3 in [001] projection for 200 keV electrons.

Keywords

STEM-EDSfast chemical imagingatomic-scalethin specimenelemental mapping
Type
Materials Applications
Information
Microscopy and Microanalysis , Volume 23 , Issue 1 , February 2017 , pp. 145 - 154
Copyright
© Microscopy Society of America 2017 

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References

Allen, L.J., D’Alfonso, A.J., Freitag, B. & Klenov, D.O. (2012). Chemical mapping at atomic resolution using energy-dispersive X-ray spectroscopy. MRS Bull 37, 47–52.CrossRefGoogle Scholar
Allen, L.J., Findlay, S.D., Lupini, A.R., Oxley, M.P. & Pennycook, S.J. (2003). Atomic-resolution electron energy loss spectroscopy imaging in aberration corrected scanning transmission electron microscopy. Phys Rev Lett 91, 105503.CrossRefGoogle ScholarPubMed
Bosman, M., Keast, V.J., García-Muñoz, J.L., D’Alfonso, A.J.,Findlay, S.D. & Allen, L.J. (2007). Two-dimensional mapping of chemical information at atomic resolution. Phys Rev Lett 99, 086102.CrossRefGoogle ScholarPubMed
Browning, N.D., Chisholm, M.F. & Pennycook, S.J. (1993). Atomic-resolution chemical analysis using a scanning transmission electron microscope. Nature 366, 143.CrossRefGoogle Scholar
Cherns, D., Howie, A. & Jacobs, M.H. (1973). Characteristic X-ray production in thin crystals. Z Naturforsch 28 A, 565–571.CrossRefGoogle Scholar
Chen, Z., Weyland, M., Sang, X., Xu, W., Dycus, J.H., LeBeau, J.M., D’Alfonso, A.J., Allen, L.J. & Findlay, S.D. (2016). Quantitative atomic resolution elemental mapping via absolute-scale energy dispersive X-ray spectroscopy. Ultramicroscopy 168, 7–16.CrossRefGoogle ScholarPubMed
Chu, M.W., Liou, S.C., Chang, C.P., Choa, F.S. & Chen, C.H. (2010). Emergent chemical mapping at atomic-column resolution by energy-dispersive X-ray spectroscopy in an aberration-corrected electron microscope. Phys Rev Lett 104, 196101.CrossRefGoogle Scholar
Cowley, J.M. (1984). Diffraction Physics, 2nd ed. New York: Elsevier Science Publishing.Google Scholar
D’Alfonso, A.J., Freitag, B., Klenov, V. & Allen, L.J. (2010). Atomic-resolution chemical mapping using energy-dispersive X-ray spectroscopy. Phys Rev B 81, 100101.CrossRefGoogle Scholar
Forbes, B.D., D’Alfonso, A.J., Williams, R.E.A., Srinivasan, R., Fraser, H.L., McComb, D.W., Freitag, B., Klenov, D.O. & Allen, L.J. (2012). Contribution of thermally scattered electrons to atomic resolution elemental maps. Phys Rev B 86, 24108.CrossRefGoogle Scholar
Kimoto, K., Asaka, T., Nagai, T., Saito, M., Matsui, Y. & Ishizuka, k. (2007). Element-selective imaging of atomic columns in a crystal using STEM and EELS. Nature 450, 702.CrossRefGoogle Scholar
Kirkland, A.I. & Saxton, W.O. (2002). Cation segregation in Nb16W18O94 using high angle annular dark field scanning transmission electron microscopy and imaging processing. J Microsc 206, 1–6.CrossRefGoogle Scholar
Lu, P., Romero, E., Lee, S., MacManus-Driscoll, J.L. & Jia, Q. (2014b). Chemical quantification of atomic-scale EDS maps under thin specimen conditions. Microsc Microanal 20, 1782–1790.CrossRefGoogle ScholarPubMed
Lu, P., Xiong, J., Van Benthem, M. & Jia, Q.X. (2013). Atomic-scale chemical quantification of oxide interfaces using energy-dispersive X-ray spectroscopy. App Phys Lett 102, 173111.CrossRefGoogle Scholar
Lu, P., Yuan, R.L., Ihlefeld, J.F., Spoerke, E.D., Pan, W. & Zuo, J.M. (2016). Fast atomic-scale chemical imaging of crystalline materials and dynamic phase transformations. Nano Lett 16, 2728–2733.CrossRefGoogle ScholarPubMed
Lu, P., Zhou, L., Kramer, M.J. & Smith, D.J. (2014a). Atomic-scale chemical imaging and quantification of metallic alloy structures by energy-dispersive X-ray spectroscopy. Sci Rep 4, 3945.CrossRefGoogle ScholarPubMed
Muller, D.A., Fitting Kourkoutis, L., Murfitt, M., Song, J.H., Hwang, H.Y., Silcox, J., Dellby, N. & Krivanek, O.L. (2008). Atomic-scale chemical imaging of composition and bonding by aberration-corrected microscopy. Science 319, 1073.CrossRefGoogle ScholarPubMed
Oxley, M.P., Varela, M., Pennycook, T.J., van Benthem, K., Findlay, S.D., D’Alfonso, A.J., Allen, L.J. & Pennycook, S.J. (2007). Interpreting atomic-resolution spectroscopic images. Phys Rev B 76, 064303.CrossRefGoogle Scholar
Saxton, W.O. & Baumeister, W. (1982). The correlation averaging of a regularly arranged bacterial cell envelop protein. J Microsc 127, 127–138.CrossRefGoogle Scholar
Spence, J.C.H. & Zuo, J.M. (1992). Electron Microdiffraction. New York: Plenum Press.CrossRefGoogle Scholar
Watanabe, M., Kanno, M. & Okunishi, E. (2010). Atomic-resolution elemental mapping by EELS and XEDS in aberration corrected STEM. JEOL News 45, 8–15.Google Scholar
Williams, D.B. & Carter, C.B. (1996). Transmission Electron Microscopy. New York: Springer.CrossRefGoogle Scholar