The transmission electron microscope (TEM) uses the physical and atomic phenomena produced when a sufficiently accelerated electron beam collides with a suitably prepared thin sample. When the electrons collide with a sample, depending on its thickness and the type of atoms in the sample, some of them disperse selectively, i.e., there is a gradation between the electrons that pass through it directly and those that are fully diverted. They are all driven and modulated by lenses that form a final image on a CCD that can be magnified thousands of times with a definition that is unattainable for any other instrument. The information obtained is an image with different intensities of grey corresponding to the level of dispersion of the incident electrons.

The TEM image described offers information on the sample structure, whether amorphous or crystalline.

Furthermore, if the sample is crystalline -in other words, there is a periodic plane structure- various families of these planes may meet the Bragg condition and coherently diffract the incident electron wave. The result is a diffraction diagram, which is an image of different points ordered with respect to a central point (non-deviated transmitted electrons); this offers information on the orientation and structure of the crystal/crystals present.