Hostname: page-component-586b7cd67f-t7fkt Total loading time: 0 Render date: 2024-11-22T18:51:55.176Z Has data issue: false hasContentIssue false
  • English
  • Français

Off-Axis STEM or TEM Holography Combined with Four-Dimensional Diffraction Imaging

Published online by Cambridge University Press:  22 January 2004

J.M. Cowley
J.M. Cowley
Affiliation:
Department of Physics and Astronomy, Arizona State University, Tempe, AZ 85287-1504, USA
Get access

Abstract

Ultrahigh-resolution imaging may be achieved using modifications of the off-axis holography scheme in a scanning transmission electron microscopy (STEM) instrument equipped with one or more electrostatic biprisms in the illuminating system. The resolution is governed by the diameter of a reference beam, reduced by channeling through a line of atoms in an atomic-focuser crystal. Alternatively, the off-axis holography may be combined with the Rodenburg method in which a four-dimensional data set is obtained by recording a nanodiffraction pattern from each point of the specimen as the incident beams are scanned. An ultrahigh-resolution image is derived by computer processing to give a particular two-dimensional section of this data set. The large amount of data recording and data processing involved with this method may be avoided if the two-dimensional section is derived by recording the hologram while the four beams produced by two perpendicular biprisms are scanned in opposing directions across the specimen by varying the voltages on the biprisms. An equivalent scheme for conventional TEM is also possible. In each case, the complex transmission function of the specimen may be derived and resolutions of about 0.05 nm may be expected.

Keywords

scanning transmission electron microscopyoff-axis electron holographyatomic-focuser channelingfour-dimensional diffraction imagingultrahigh resolution
Type
Research Article
Information
Microscopy and Microanalysis , Volume 10 , Issue 1 , February 2004 , pp. 9 - 15
Copyright
© 2004 Microscopy Society of America

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Batson, P.E., Dellby, N., & Krivanek, O.L. (2002). Sub-Ångstrom resolution using aberration corrected electron optics. Nature 418, 617–620.Google Scholar
Cowley, J.M. (1992). Twenty forms of electron holography. Ultramicroscopy 41, 335–348.Google Scholar
Cowley, J.M. (2001). Comments on ultra-high resolution STEM. Ultramicroscopy 87, 1–4.Google Scholar
Cowley, J.M. (2003). Ultra-high resolution with off-axis STEM holography. Ultramicroscopy 96, 163–166.Google Scholar
Cowley, J.M., Dunin-Borkowski, R.E., & Hayward, M. (1998). The contrast of images formed by atomic focusers. Ultramicroscopy 72, 223–232.Google Scholar
Cowley, J.M. & Hudis, J.B. (2000). Atomic focuser imaging by graphite crystals in carbon nanoshells. Microsc Microanal 6, 429–436.Google Scholar
Cowley, J.M., Spence, J.C.H., & Smirnov, V.V. (1997). The enhancement of electron microscope resolution by use of atomic focusers. Ultramicroscopy 68, 135–148.Google Scholar
Cowley, J.M. & Winterton, J. (2001). Ultra-high-resolution electron microscopy of carbon nanotube walls. Phys Rev Lett 87, 016101-1–016101-4.Google Scholar
Dunin-Borkowski, R.E. & Cowley, J.M. (1999). Simulations for imaging with atomic focusers. Acta Cryst A 55, 119–126.Google Scholar
Gabor, D. (1948). A new microscope principle. Nature 161, 777–778.Google Scholar
Lentzen, M., Jahnen, B., Jia, C.L., Thust, A., Tilmann, K., & Urban, K. (2002). High-resolution imaging with an aberration-corrected transmission electron microscope. Ultramicroscopy 92, 233–242.Google Scholar
Lin, J.A. & Cowley, J.M. (1986). Reconstruction from in-line holograms by digital processing. Ultramicroscopy 19, 179–190.Google Scholar
McCallum, B.C. & Rodenburg, J.D. (1992). Two-dimensional demonstration of Wigner phase-retrieval microscopy in the STEM configuration. Ultramicroscopy 45, 371–380.Google Scholar
O'Keefe, M.A., Hetherington, C.J.D., Wang, Y.C., Nelson, E.C., Turner, J.H., Kisielowski, C., Malm, J.-O., Mueller, R., Ringnalda, J., Pan, M., & Thust, A. (2001). Sub-Ångstrom high-resolution transmission electron microscopy at 300 keV. Ultramicroscopy 89, 215–241.Google Scholar
Rau, W.D. & Lichte, H. (1998). High resolution off-axis holography. In Introduction to Electron Holography, Volkl, E., Allard, L.F. & Joy, D.C. (Eds.), pp. 201–229. New York: Kluwer Academic/Plenum Publishers.
Rodenburg, J.D., McCallum, B.C., & Nellist, P.D. (1993). Experimental tests on double-resolution coherent imaging via STEM. Ultramicroscopy 48, 304–314.Google Scholar
Sanchez, M. & Cowley, J.M. (1998). The imaging properties of atomic focusers. Ultramicrsocopy 72, 213–222.Google Scholar
Smirnov, V.V. (1998). Atomic focusers. J Phys D, Appl Phys 31, 1548–1555.Google Scholar
Smirnov, V.V. & Cowley, J.M. (2002). In-line electron holography with an atomic-focuser source. Phys Rev B 65, 064109-1–064109-9.Google Scholar
Spargo, A.E.C., Beeching, M., & Allen, L.J. (1994). Inversion of electron scattering intensity for crystal structure analysis. Ultramicroscopy 55, 329–333.Google Scholar
Spence, J.C.H. (1998). Direct inversion of dynamical electron diffraction patterns to structure factors. Acta Cryst A 54, 7–18.Google Scholar