Retrieving the energy-loss function from valence electron energy-loss spectrum: Separation of bulk-, surface-losses and Cherenkov radiation

Ultramicroscopy
Qingping MengYimei Zhu

Abstract

With recent rapid advancement in electron microscopy instrumentation, in particular, bright electron sources and monochromators, valence electron energy-loss spectroscopy (VEELS) has become attractive for retrieving band structures, optical properties, dielectric functions and phonon information of materials. However, Cherenkov radiation and surface-loss contribution significantly alter fine structures of VEELS, even in simple semiconductors and insulators. This leads to the problem that dielectric function or bandgap structure of these materials cannot be determined correctly if these effects are not removed. In this work we present a solution to this dilemma. We demonstrate that energy-loss function and real part of inverse complex dielectric function can be retrieved from raw data of VEELS. Based on the calculated example of Si, the limitation of our approach is discussed. We believe that our approach represents an improvement over previous procedures and has a broad prospect for applications.

References

Mar 23, 2006·Micron : the International Research and Review Journal for Microscopy·M Stöger-PollachH W Zandbergen
Apr 3, 2007·Ultramicroscopy·M Stöger-Pollach, P Schattschneider
Aug 11, 2007·Ultramicroscopy·M Stöger-PollachP Schattschneider
Apr 9, 2008·Micron : the International Research and Review Journal for Microscopy·M Stöger-Pollach

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Citations

Jan 9, 2021·The Journal of Chemical Physics·Nikolay BorodinovJordan A Hachtel
May 6, 2019·The Journal of Physical Chemistry. a·Qingping MengDong Su

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