TY  - JOUR
AU  - Grieb, Tim
AU  - Krause, Florian F.
AU  - Müller-Caspary, Knut
AU  - Firoozabadi, Saleh
AU  - Mahr, Christoph
AU  - Schowalter, Marco
AU  - Beyer, Andreas
AU  - Oppermann, Oliver
AU  - Volz, Kerstin
AU  - Rosenauer, Andreas
TI  - Angle-resolved STEM using an iris aperture: Scattering contributions and sources of error for the quantitative analysis in Si
JO  - Ultramicroscopy
VL  - 221
SN  - 0304-3991
CY  - Amsterdam
PB  - Elsevier Science
M1  - FZJ-2021-02887
SP  - 113175 -
PY  - 2021
AB  - The angle-resolved electron scattering is investigated in scanning-transmission electron microscopy (STEM) using a motorised iris aperture placed above a conventional annular detector. The electron intensity scattered into various angle ranges is compared with simulations that were carried out in the frozen-lattice approximation. As figure of merit for the agreement of experiment and simulation we evaluate the specimen thickness which is compared with the thickness obtained from position-averaged convergent beam electron diffraction (PACBED). We find deviations whose strengths depend on the angular range of the detected electrons. As possible sources of error we investigate, for example, the influences of amorphous surface layers, inelastic scattering (plasmon excitation), phonon-correlation within the frozen-lattice approach, and distortions in the diffraction plane of the microscope. The evaluation is performed for four experimental thicknesses and two angle-resolved STEM series under different camera lengths. The results clearly show that especially for scattering angles below 50 mrad, it is mandatory that the simulations take scattering effects into account which are usually neglected for simulating high-angle scattering. Most influences predominantly affect the low-angle range, but also high scattering angles can be affected (e.g. by amorphous surface covering).
LB  - PUB:(DE-HGF)16
C6  - 33383361
UR  - <Go to ISI:>//WOS:000613507200002
DO  - DOI:10.1016/j.ultramic.2020.113175
UR  - https://juser.fz-juelich.de/record/893875
ER  -