Advances in EELS spectroscopy by using new detector and new specimen preparation technologies.
First results obtained with a Gatan UHV Enfina system, which was attached to a VG HB 501 UX dedicated STEM, are reported. The Enfina system is based on a CCD detector and offers, compared to the previously used photodiode array, a narrower point-spread function, higher sensitivity, and faster read-out capabilities. These improvements are demonstrated with electron energy-loss measurements on various oxides, such as Al2O3, TiO2 and SrTiO3. It is shown that a better energy resolution is achieved and that acquisition of high-energy absorption edges with a reasonable signal-to-noise ratio becomes possible. Furthermore, we report on the influence of the TEM specimen quality on the energy-loss spectra. Thin amorphous layers at the specimen surfaces, which are induced by ion-milling processes, can modify specific electron energy-loss near-edge structure features. We found that for the investigated ceramics the use of low-energy ion-milling systems is highly recommended, since the loss of energy-loss near-edge structure details by the presence of the amorphous layers is considerably reduced. This is especially true for very thin specimens.
Scheu
C
C
Max-Planck-Institut für Metallforschung, Heisenbergstr. 3, Stuttgart 70569, Germany. scheu@hrem.mpi-stuttgart.mpg.de
Gao
M
M
Van Benthem
K
K
Tsukimoto
S
S
Schmidt
S
S
Sigle
W
W
Richter
G
G
Thomas
J
J