Hostname: page-component-cd9895bd7-gxg78 Total loading time: 0 Render date: 2024-12-23T00:08:13.508Z Has data issue: false hasContentIssue false
  • English
  • Français

Preliminary Results from the First Monochromated and Aberration Corrected 200-kV Field-Emission Scanning Transmission Electron Microscope

Published online by Cambridge University Press:  11 October 2006

Thomas Walther  and
Heiko Stegmann
Thomas Walther
Affiliation:
Center of Advanced European Studies and Research (caesar), Electron Microscopy Group, Ludwig-Erhard-Allee 2, D-53175 Bonn, Germany
Heiko Stegmann
Affiliation:
Carl Zeiss Nano Technology Systems GmbH, Carl-Zeiss-Str. 56, D-73447 Oberkochen, Germany
Get access

Abstract

Experimental results from the first monochromated and aberration-corrected scanning transmission electron microscope operated at 200 kV are described. The formation of an electron probe with a diameter of less than 0.2 nm at an energy width significantly under 0.3 eV and its planned application to the chemical analysis of nanometer-scale structures in materials science are described. Both energy and spatial resolution will benefit from this: The monochromator improves the energy resolution for studies of energy loss near edge structures. The Cs corrector allows formation of either a smaller probe for a given beam current or yields, at fixed probe size, an enhanced beam current density using a larger condenser aperture. We also point out another advantage of the combination of both components: Increasing the convergence angle by using larger condenser apertures in an aberration-corrected instrument will enlarge the undesirable chromatic focus spread. This in turn influences spatial resolution. The effect of polychromatic probe tails is proportional to the product of convergence angle, chromatic aberration constant, and energy spread. It can thus be compensated for in our new instrument by decreasing the energy width by the same factor as the beam convergence is increased to form a more intense probe. An alternative in future developments might be hardware correction of the chromatic aberration, which could eliminate the chromatic probe spread completely.

Keywords

scanning transmission electron microscopy (STEM)monochromatorspherical aberrationCs correctorchromatic focus spreadannular dark field (ADF) imagingelectron energy-loss spectroscopy (EELS)
Type
Research Article
Information
Microscopy and Microanalysis , Volume 12 , Issue 6: Special Issue: Frontiers of Electron Microscopy in Materials Science , December 2006 , pp. 498 - 505
Copyright
© 2006 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. (2003). Aberration correction results in the IBM STEM instrument. Ultramicroscopy 96, 239–249.Google Scholar
Dellby, N., Krivanek, O.L., Nellist, P.D., Batson, P.E., & Lupini, A.R. (2001). Progress in aberration-corrected scanning transmission electron microscopy. J Electron Microsc 50, 177–185.Google Scholar
Erni, R. & Browning, N.D. (2005). Valence electron energy-loss spectroscopy in monochromated scanning transmission electron microscopy. Ultramicroscopy 104, 176–192.Google Scholar
Esumi, K., Kameo, A., Suzuki, A., & Torigoe, K. (2001). Preparation of gold nanoparticles in formamide and N,N-dimethylformamide in the presence of poly(amidoamine) dendrimers with surface methyl ester groups. Colloids Surf A 189, 155–161.Google Scholar
Haider, M., Rose, H., Uhlemann, S., Kabius, K., & Urban, K. (1998a). Towards 0.1 nm resolution with the first spherically corrected transmission electron microscope. J Electron Microsc 47, 395–405.Google Scholar
Haider, M., Rose, H., Uhlemann, S., Schwan, E., Kabius, B., & Urban, K. (1998b). A spherical-aberration-corrected 200 kV transmission electron microscope. Ultramicroscopy 75, 53–60.Google Scholar
Hutchison, J.L., Titchmarsh, J.M., Cockayne, D.J.H., Doole, R.C., Hetherington, C.J.D., Kirkland, A.I., & Sawada, H. (2005). A versatile double aberration-corrected, energy-filtered HREM/STEM for materials science. Ultramicroscopy 103, 7–15.Google Scholar
Krause, M.O. & Oliver, J.H. (1979). Natural widths of atomic K and L levels. J Phys Chem Ref Data 8, 329–338.Google Scholar
Kreibig, U. & Zacharias, P. (1970). Surface plasma resonances in small spherical silver and gold particles. Z Phys 213, 128–143.Google Scholar
Krivanek, O.L., Nellist, P.D., Dellby, N., Murfitt, M.F., & Szilagyi, Z. (2003). Towards sub-Å electron beams. Ultramicroscopy 96, 229–237.Google Scholar
Lazar, S., Botton, G.A., Wu, M.-Y., Tichelaar, F.D., & Zandbergen, H.W. (2003). Materials science applications of HREELS in near edge structure analysis and low-energy loss spectroscopy. Ultramicroscopy 96, 535–546.Google Scholar
Martinez, G. & Tsuno, K. (2004). Design of Wien filters with high resolution. Ultramicroscopy 100, 105–114.Google Scholar
Mook, H.W. & Kruit, P. (1999). Optics and design of the fringe field monochromator for a Schottky field emission gun. Nucl Instrum Methods Phys Res A 427, 109–120.Google Scholar
Nashner, M.S., Frenkel, A.I., Somerville, D., Hills, C.W., Shapley, J.R., & Nuzzo, R.G. (1998). Core shell inversion during nucleation and growth of bimetallic Pt/Ru nanoparticles. J Am Chem Soc 120, 8093–8101.Google Scholar
Reimer, L. (1984). Transmission Electron Microscopy. Physics of Image Formation and Microanalysis. Berlin: Springer-Verlag.
Rose, H. (1990a). Electrostatic energy filter as monochromator of a highly coherent electron source. Optik 86, 95–98.Google Scholar
Rose, H. (1990b). Outline of a spherically corrected semiaplanatic medium-voltage transmission electron-microscope. Optik 85, 19–24.Google Scholar
Samet, L., Imhoff, D., Maurice, J.L., Contour, J.P., Gloter, A., Manoubi, T., Fert, A., & Colliex, C. (2003). EELS study of interfaces in magnetoresistive LSMO/STO/LSMO tunnel junctions. Eur Phys J B Condens Matter 34, 179–192.Google Scholar
Terauchi, M., Tanaka, M., Tsuno, K., & Ishida, M. (1999). Development of a high energy resolution electron energy-loss spectroscopy microscope. J Microsc 194, 203–209.Google Scholar
Tiemeijer, P.C. (1999). Measurement of Coulomb interactions in an electron beam monochromator. Ultramicroscopy 78, 53–62.Google Scholar
Uhlemann, S. & Haider, M. (1998). Residual wave aberrations in the first spherical aberration corrected transmission electron microscope. Ultramicroscopy 72, 109–119.Google Scholar
Uhlemann, S. & Haider, M. (2002). Experimental set-up of a fully electrostatic monochromator for a 200kV TEM. In Proceedings of the 15th International Conference on Electron Microscopy, (Durban, South Africa), Cross, R., Engelbrecht, J., Sewell, T. & Witcomb, M. (Eds.), vol. 3, pp. 327–328. Onderstepoort, South Africa: Microscopy Society of Southern Africa.
Walther, T. (2006). A new experimental procedure to quantify annular dark field images in scanning transmission electron microscopy. J Microsc 221, 137–144.Google Scholar
Walther, T., Quandt, E., Stegmann, H., Thesen, A., & Benner, G. (2006). First experimental test of a new monochromated and aberration corrected 200 kV field-emission scanning transmission electron microscope [http://dx.doi.org, DOI: 10.1016/j.ultramic.2006.04.14]. Ultramicroscopy, in press.Google Scholar
Zaluzec, N.J. (1995). The ANL advanced AEM project. AAEMfigure6.gif of the report published online at: http://146.139.72.10/docs/anl/AAEM.