The HAADF signal (left) contrast is easily interpreted in terms of mass thickness of the material while the diffraction contrast MAADF signal (right) reveals highly detailed structural changes in the material. The optimized geometry makes this possible.
Using examples from various domains of science, this review covers some recent developments in spectrum imaging (SI) using scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS).
Paolo Longo, Ph.D., Gatan, Inc.
Sample courtesy of Dr. P. Rice and Dr. T. Topuria at IBM (Almaden), San Jose, CA
Microscope courtesy of Dr. Giuseppe Nicotra, IMM-CNR, Catania, Italy
The lab where EELS maps were taken is situated at the slopes of Mount Etna in Sicily, Italy. Mount Etna is the highest active volcano in Europe. The EELS elemental maps were taken at high speed during major volcano eruption, as shown in the volcano webcam photograph above the maps.