Scanning Electron Microscopy Basic Operating Mode
NREL uses scanning electron microscopy in its basic operating mode to sense secondary electrons and X-rays emitted from a materials sample.
The former provides high-resolution topography, and the latter indicates elemental composition.
Backscattered electron emission is sensitive to composition. Energy transfer from incident electrons to the specimen produces X-rays characteristic of the specimen's elemental composition by energy-dispersive spectroscopy (EDS). Elements are identified on the energy-resolved spectrum of X-rays by their characteristic lines. Synchronizing the scanning of the electron beam with the readout of the EDS detector can generate elemental maps with micrometric resolution. Under well-controlled conditions, the composition of the specimen can be quantified with an accuracy of 1%–3%.