[Zurück]

M. Stöger-Pollach, K. Bukvisová, S. Schwarz, M. Kvapil, T. Samoril, M. Horák:
"Fundamentals of cathodoluminescence in a STEM: The impact of sample geometry and electron beam energy on light emission of semiconductors";
Ultramicroscopy, 200 (2019), S. 111 - 124.

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 find 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 reflection 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.

Cathodoluminescence, Čerenkov radiation, Transition radiation, STEM

http://dx.doi.org/10.1016/j.ultramic.2019.03.001