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Extended Depth of Field for High-Resolution Scanning Transmission Electron Microscopy

Published online by Cambridge University Press:  02 December 2010

Robert Hovden ,
Huolin L. Xin  and
David A. Muller
Robert Hovden*
Affiliation:
School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853, USA
Huolin L. Xin
Affiliation:
Department of Physics, Cornell University, Ithaca, NY 14853, USA
David A. Muller
Affiliation:
School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853, USA Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY 14853, USA
*
Corresponding author. E-mail: [email protected]
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Abstract

Aberration-corrected scanning transmission electron microscopes (STEMs) provide sub-Angstrom lateral resolution; however, the large convergence angle greatly reduces the depth of field. For microscopes with a small depth of field, information outside of the focal plane quickly becomes blurred and less defined. It may not be possible to image some samples entirely in focus. Extended depth-of-field techniques, however, allow a single image, with all areas in focus, to be extracted from a series of images focused at a range of depths. In recent years, a variety of algorithmic approaches have been employed for bright-field optical microscopy. Here, we demonstrate that some established optical microscopy methods can also be applied to extend the ∼6 nm depth of focus of a 100 kV 5th-order aberration-corrected STEM (αmax = 33 mrad) to image Pt-Co nanoparticles on a thick vulcanized carbon support. These techniques allow us to automatically obtain a single image with all the particles in focus as well as a complimentary topography map.

Keywords

depth of fieldaberration correctedSTEMdepth sectioningdeconvolution
Type
TEM and STEM Materials Applications
Information
Microscopy and Microanalysis , Volume 17 , Issue 1 , February 2011 , pp. 75 - 80
Copyright
Copyright © Microscopy Society of America 2011

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