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Simplifying Electron Beam Channeling in Scanning Transmission Electron Microscopy (STEM)

Published online by Cambridge University Press:  04 July 2017

Ryan J. Wu ,
Anudha Mittal ,
Michael L. Odlyzko  and
K. Andre Mkhoyan
Ryan J. Wu
Affiliation:
Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, USA
Anudha Mittal
Affiliation:
Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, USA
Michael L. Odlyzko
Affiliation:
Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, USA
K. Andre Mkhoyan*
Affiliation:
Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, USA
*
*Corresponding author. mkhoyan@umn.edu
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Abstract

Sub-angstrom scanning transmission electron microscopy (STEM) allows quantitative column-by-column analysis of crystalline specimens via annular dark-field images. The intensity of electrons scattered from a particular location in an atomic column depends on the intensity of the electron probe at that location. Electron beam channeling causes oscillations in the STEM probe intensity during specimen propagation, which leads to differences in the beam intensity incident at different depths. Understanding the parameters that control this complex behavior is critical for interpreting experimental STEM results. In this work, theoretical analysis of the STEM probe intensity reveals that intensity oscillations during specimen propagation are regulated by changes in the beam’s angular distribution. Three distinct regimes of channeling behavior are observed: the high-atomic-number (Z) regime, in which atomic scattering leads to significant angular redistribution of the beam; the low-Z regime, in which the probe’s initial angular distribution controls intensity oscillations; and the intermediate-Z regime, in which the behavior is mixed. These contrasting regimes are shown to exist for a wide range of probe parameters. These results provide a new understanding of the occurrence and consequences of channeling phenomena and conditions under which their influence is strengthened or weakened by characteristics of the electron probe and sample.

Keywords

STEMmultislicechannelingZ-dependence
Type
Instrumentation and Software
Information
Microscopy and Microanalysis , Volume 23 , Issue 4 , August 2017 , pp. 794 - 808
Copyright
© Microscopy Society of America 2017 

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References

Borisevich, A.Y., Lupini, A.R. & Pennycook, S.J. (2006). Depth sectioning with the aberration-corrected scanning transmission electron microscope. Proc Natl Acad Sci U S A 103, 3044–3048.Google Scholar
Cowley, J.M. & Moodie, A.F. (1957). The scattering of electrons by atoms and crystals: A new theoretical approach. Acta Crystallogr A 10, 609–619.CrossRefGoogle Scholar
D’Alfonso, A.J., Findlay, S.D., Oxley, M.P., Pennycook, S.J., van Benthem, K. & Allen, L.J. (2007). Depth sectioning in scanning transmission electron microscopy based on core-loss spectroscopy. Ultramicroscopy 108, 17–28.CrossRefGoogle ScholarPubMed
Davey, W.P. (1925). Precision measurements of the lattice constants of twelve common metals. Phys Rev Lett 25, 753–761.Google Scholar
Egerton, R.F. (2011). Electron Energy Loss Spectroscopy in the Electron Microscope, 3rd ed. New York: Springer.Google Scholar
Ewald, P. P. (1921). Die Berechnung optischer und elektrostatischer Gitterpotentiale. Ann Phys 369, 253–287.Google Scholar
Fertig, J. & Rose, H. (1981). Resolution and contrast of crystalline objects in high-resolution scanning transmission electron microscopy. Optik 59, 407–429.Google Scholar
Giannozzi, P., Baroni, S., Bonini, N., Calandra, M., Car, R., Cavazzoni, C., Ceresoli, D., Chiarotti, G.L., Cococcioni, M., Dabo, I., Corso, A.D., de Gironcoli, S., Fabris, S., Fratesi, G., Gebauer, R., Gerstmann, U., Gougoussis, C., Kokalj, A., Lazzeri, M., Martin-Samos, L., Marzari, N., Mauri, F., Mazzarello, R., Paolini, S., Pasquarello, A., Paulatto, L., Sbraccia, C., Scandolo, S., Sclauzero, G., Smogunov, A.P., Umari, P. & Wentzcovitch, R.M. (2009). QUANTUM ESPRESSO: a modular and open-source software project for quantum simulations of materials. J Phys Condens Matter 21, 399502.CrossRefGoogle ScholarPubMed
Haruta, M., Kurata, H., Komatsu, H., Shimakawa, Y. & Isoda, S. (2009). Effects of electron channeling in HAADF-STEM intensity in La2CuSnO6 . Ultramicroscopy 109, 361–367.CrossRefGoogle ScholarPubMed
Hillyard, S., Loane, R.F. & Silcox, J. (1993). Annular dark-field imaging: Resolution and thickness effects. Ultramicroscopy 49, 14–25.CrossRefGoogle Scholar
Hillyard, S. & Silcox, J. (1993). Thickness effects in ADF STEM zone axis images. Ultramicroscopy 52, 325–334.Google Scholar
Hillyard, S. & Silcox, J. (1995). Detector geometry, thermal diffuse scattering and strain effects in ADF STEM imaging. Ultramicroscopy 58, 6–17.CrossRefGoogle Scholar
Hovden, R., Xin, H.L. & Muller, D.A. (2012). Channeling of a subangstrom electron beam in a crystal mapped to two-dimensional molecular orbitals. Phys Rev B 86, 195415.Google Scholar
Hwang, J., Zhang, J.Y., D’Alfonso, A.J., Allen, L.J. & Stemmer, S. (2013). Three-dimensional imaging of individual dopant atoms in SrTiO3 . Phys Rev Lett 111, 266101.Google Scholar
Ishikawa, R., Lupini, A.R., Findlay, S.D., Taniguchi, T. & Pennycook, S.J. (2014). Three-dimensional location of a single dopant with atomic precision by aberration corrected scanning transmission electron microscopy. Nano Lett 14, 1903–1908.Google Scholar
Kambe, K., Lehmpfuhl, G. & Fujimoto, F. (1974). Interpretation of electron channeling by the dynamical theory of electron diffraction. Z Naturforschung 29, 1034–1044.CrossRefGoogle Scholar
Kirkland, E.J. (2010). Advanced Computing in Electron Microscopy, 2nd ed New York: Springer.Google Scholar
Komaki, K. & Fujimoto, F. (1974). Quantized rosette motion of energetic electron around an atomic row in crystal. Phys Lett A 49, 445–446.CrossRefGoogle Scholar
Kourkoutis, L.F., Parker, M.K., Vaithyanathan, V., Schlom, D.G. & Muller, D.A. (2011). Direct measurement of electron channeling in a crystal using scanning transmission electron microscopy. Phys Rev B 84, 075485.Google Scholar
Kreiner, H.J., Bell, F., Sizmann, R., Harder, D. & Hüttl, W. (1970). Rosette motion in negative particle channelling. Phys Lett A 33, 135–136.Google Scholar
LeBeau, J.M., Findlay, S.D., Allen, L.J. & Stemmer, S. (2008). Quantitative atomic resolution scanning transmission electron microscopy. Phys Rev Lett 100, 206101.Google Scholar
LeBeau, J.M., Findlay, S.D., Wang, X., Jacobson, A.J., Allen, L.J. & Stemmer, S. (2009). High-angle scattering of fast electrons from crystals containing heavy elements. Phys Rev B 79, 214110.Google Scholar
LeBeau, J.M., Findlay, S.D., Allen, L.J. & Stemmer, S. (2010). Standardless atom counting in scanning transmission electron microscopy. Nano Lett 10, 4405–4408.CrossRefGoogle ScholarPubMed
Lindhard, J. (1965). Influence of crystal lattice on the motion of energetic charged particles. Kongel Dan Vidensk Selsk Mat Fys Medd 34, 14.Google Scholar
Loane, R.F., Kirkland, E.J. & Silcox, J. (1988). Visibility of single heavy atoms on thin crystalline silicon in simulated annular dark-field STEM images. Acta Crystallogr Sect A 44, 912–927.Google Scholar
Loane, R.F., Xu, P. & Silcox, J. (1991). Thermal vibrations in convergent-beam electron diffraction. Acta Crystallogr A 47, 267–278.Google Scholar
Lugg, N.R., Findlay, S.D., Shibata, N., Mizoguchi, T., D’Alfonso, A.J., Allen, L.J. & Ikuhara, Y. (2011). Scanning transmission electron microscopy imaging dynamics at low accelerating voltages. Ultramicroscopy 111, 999–1013.Google Scholar
Mittal, A. (2013). A theoretical study of dopant atom detection and probe behavior in STEM. PhD Thesis. University of Minnesota, Minneapolis, MN.Google Scholar
Mittal, A. & Mkhoyan, K.A. (2011). Limits in detecting an individual dopant atom embedded in a crystal. Ultramicroscopy 111, 1101–1110.Google Scholar
Mkhoyan, K.A., Maccagnano-Zacher, S.E., Kirkland, E.J. & Silcox, J. (2008). Effects of amorphous layers on ADF-STEM imaging. Ultramicroscopy 108, 791–803.Google Scholar
Nellist, P.D. & Pennycook, S.J. (1999). Incoherent imaging using dynamically scattered coherent electrons. Ultramicroscopy 78, 111–124.Google Scholar
Odlyzko, M.L., Held, J.T. & Mkhoyan, K.A. (2016). Atomic bonding effects in annular dark field scanning transmission electron microscopy. II. Experiments. J Vac Sci Technol A 34, 041603.CrossRefGoogle Scholar
Op de Beeck, M. & Van Dyck, D. (1996). Direct structure reconstruction in HRTEM. Ultramicroscopy 64, 153–165.Google Scholar
Pennycook, S.J. (1988). Delocalization corrections for electron channeling analysis. Ultramicroscopy 26, 239–248.Google Scholar
Pennycook, S.J. & Jesson, D.E. (1991). High-resolution Z-contrast imaging of crystals. Ultramicroscopy 37, 14–38.Google Scholar
Perdew, J.P., Burke, K. & Ernzerhof, M. (1996). Generalized gradient approximation made simple. Phys Rev Lett 77, 3865–3868.Google Scholar
Schowalter, M., Rosenauer, A., Titantah, J.T. & Lamoen, D. (2009). Computation and parametrization of the temperature dependence of Debye-Waller factors for group IV, III-V, and II-VI semiconductors. Acta Crystallogr A 65, 5–17.Google Scholar
Sinkler, W. & Marks, L.D. (1999). A simple channelling model for HREM contrast transfer under dynamical conditions. J Microsc 194, 112–123.CrossRefGoogle ScholarPubMed
Tsyganov, E.N. (1976). Some aspects of the mechanism of a charge particle penetration through a monocrystal. In Fermilab. Batvia, IL: Fermi National Accelator Laboratory.Google Scholar
van den Bos, K.H.W., De Backer, A., Martinez, G.T., Winckelmans, N., Bals, S., Nellist, P.D. & Van Aert, S. (2016). Unscrambling mixed elements using high angle annular dark field scanning transmission electron microscopy. Phys Rev Lett 116, 246101.Google Scholar
Van Aert, S., Geuens, P., Van Dyck, D., Kisielowski, C. & Jinschek, J.R. (2007). Electron channelling based crystallography. Ultramicroscopy 107, 551–558.Google Scholar
Van Dyck, D. & Op de Beeck, M. (1996). A simple intuitive theory for electron diffraction. Ultramicroscopy 64, 99–107.Google Scholar
Voyles, P.M., Grazul, J.L. & Muller, D.A. (2003). Imaging individual atoms inside crystals with ADF-STEM. Ultramicroscopy 96, 251–273.Google Scholar
Voyles, P.M., Muller, D.A. & Kirkland, E.J. (2004). Depth-dependent imaging of individual dopant atoms in silicon. Microsc Microanal 10, 291–300.CrossRefGoogle ScholarPubMed
Wu, R.J., Odlyzko, M.L. & Mkhoyan, K.A. (2014). Determining the thickness of atomically thin MoS2 and WS2 in the TEM. Ultramicroscopy 147, 8–20.CrossRefGoogle ScholarPubMed
Xu, P., Loane, R.F. & Silcox, J. (1991). Energy-filtered convergent-beam electron diffraction in STEM. Ultramicroscopy 38, 127–133.CrossRefGoogle Scholar
Yu, Z. & Silcox, J. (2004). Channeling of sub-angstrom probes along isolated atomic columns. Microsc Microanal 10(S02), 570–571.Google Scholar