Mapping of valence energy losses via energy-filtered annular dark-field scanning transmission electron microscopy.
The advent of electron monochromators has opened new perspectives on electron energy-loss spectroscopy at low energy losses, including phenomena such as surface plasmon resonances or electron transitions from the valence to the conduction band. In this paper, we report first results making use of the combination of an energy filter and a post-filter annular dark-field detector. This instrumental design allows us to obtain energy-filtered (i.e. inelastic) annular dark-field images in scanning transmission electron microscopy of the 2-dimensional semiconductor band-gap distribution of a GaN/Al(45)Ga(55)N structure and of surface plasmon resonances of silver nanoprisms. In comparison to other approaches, the technique is less prone to inelastic delocalization and relativistic artefacts. The mixed contribution of elastic and inelastic contrast is discussed.
Gu
Lin
L
Max-Planck Institute for Metals Research, Stuttgart Center for Electron Microscopy, Heisenbergstrasse 3, 70569 Stuttgart, Germany. gu@mf.mpg.de
Sigle
Wilfried
W
Koch
Christoph T
CT
Nelayah
Jaysen
J
Srot
Vesna
V
van Aken
Peter A
PA