In scanning electron microscopy, an x-ray is emitted when the electron beam displaces an inner shell electron that is replaced by an outer shell electron. Because each element has a unique energy difference between outer and inner electron shells, the x-rays that are detected yield elemental identification. EDS data can be obtained at a point, along a line or mapped over an area.
EDS spectrum for elemental identification using electron microscopy
Sample structures can be physically examined and their elemental composition determined. Viewing three-dimensional images of microscopic structures only solves half the problem when analyzing samples. It is often necessary to collect more than imaging data to be able to identify the different elements in a specimen. Using EDS with SEM addesses this need for elemental analysis.