The kinds of the electron microscope

Transmission Electron Microscope (TEM): it makes it possible to watch an object by letting electrons go through it. The object is as small as less than 0.1 micrometer. 

Scanning Electron Microscope (SEM): It scans the surface of an object by letting electron beams go over it. It uses the information on the secondary electron emitted from the object to produce the images of the sample.