Images and contrasts
Scanning electron microscopy -Images, applications and developments

The scanning electron microscope is first used to obtain images of the sample surface. These images are formed mainly by surface electron emissions (secondary and backscattered electrons). In this way, different contrasts can be observed, providing a wide range of information on the sample, essentially on its relief, using secondary electrons (topographic contrast), but also on the distribution of the phases present ("atomic number" contrast), using the backscattered electron detector. In particular, this latter detector enables us to observe chemical contrasts (presence and distribution of chemical elements); it also highlights crystalline contrasts (crystallographic structure). However, to obtain quantitative results for these last two types of contrast, it is necessary to use an EDS detector and an EBSD camera respectively. Combined with these two detectors, the scanning electron microscope...