Scanning Electron Microscopy with Energy-Dispersive X-ray Spectroscopy

Scanning electron microscopy (SEM) is an observation method used as an important analytical technique in the physical, chemical and biological research. Compared with light microscope, SEM uses narrow focused high energy electron beam scanning across the surface of the sample to image objects at much greater magnification and resolution. SEM provides images with magnifications rate of 200 ~X1,000,000, which makes it a particularly important and powerful tool for visualizing sub micron-scale features. Electron beam excites atoms on the surface of the sample and thereby generates various physical information, which then is reimagined providing detailed high resolution images for the characterization of the material’s morphology.

The most common SEM detects secondary electrons (SE) and backscattered electrons (BSE) generated by beam. SE are emitted by atoms of the material through the interaction between the electron beam and the sample. BSE are the incident electrons that bounce out of the sample. They have a low energy and they are able to show differences in absorption between elements, therefore their detection helps to identify areas of differing nature in the sample.