Scanning Electron Microscopy (SEM)
In a scanning electron microscope, a tiny electron beam is focussed onto the sample. Simultaneous to scanning the beam across a selected sample area, generated signals are being recorded and thereby an image is formed pixel by pixel. In contrast to TEM methods needing very thin samples (cf. STEM, using transmitted electrons), compact samples can thus be investigated by SEM. Valuable information about morphology, surface topology and composition can be obtained. SEM microscopes achieving resolutions below 1 nm are available now.
Schematic representation of a SEM
SE detectors | SE imaging | SEM images | Dependence on voltage
If you like to play around a bit, there are virtual SEMs on the net (SEM)