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Published February 20, 2019 | Version v1
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Fundamentals of cathodoluminescence in a STEM: The impact of sample geometry and electron beam energy on light emission of semiconductors

  • 1. University Service Centre for Transmission Electron Microscopy (USTEM), Technische Universität Wien, Wiedner Hauptstrasse 8-10, 1040 Wien, Austria
  • 2. Central European Institute of Technology (CEITEC), Brno University of Technology, Purkynova 123, Brno 612 00, Czech Republic
  • 3. Institute of Physical Engineering, Brno University of Technology, Technická 2, Brno 616 69, Czech Republic

Description

Cathodoluminescence has attracted interest in scanning transmission electron microscopy
since the advent of commercial available detection systems with high efficiency, like the Gatan Vulcan or the Attolight Mönch system. In this work we discuss light emission caused by high-energy electron beams when traversing a semiconducting
specimen. We nd that it is impossible to directly interpret the spectrum of the emitted light to the inter-band transitions excited by the electron beam, because the Čerenkov effect and the related light guiding modes as well as transition radiation
is altering the spectra. Total inner re ection and subsequent interference effects are changing the spectral shape dependent on the sample shape and geometry, sample thickness, and beam energy, respectively. A detailed study on these parameters is
given using silicon and GaAs as test materials.

Notes

Part of this work was supported by MEYS CR under the projects CEITEC Nano Research Infrastructure (project No. LM2015041, 2016-2019) and CEITEC 2020 (project No. LQ1601). This research was in part supported by the SINNCE project of the European Union's Horizon 2020 programme under the grant agreement No. 810626.

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