Electron diffraction
Electron diffraction refers to the bending of electron beams around atomic structures. This behaviour, typical for waves, is applicable to electrons due to the wave–particle duality stating that electrons behave as both particles and waves. Since the diffracted beams interfere, they generate diffraction patterns widely used for analysis of the objects which caused the diffraction. Therefore, electron diffraction can also refer to derived experimental techniques used for material characterization. This technique is similar to X-ray and neutron diffraction. Electron diffraction is most frequently used in solid state physics and chemistry to study crystalline, quasi-crystalline and amorphous materials using electron microscopes. In these instruments, electrons are accelerated by an electrostatic potential in order to gain energy and shorten their wavelength. With the wavelength sufficiently short, the atomic structure acts as a diffraction grating generating diffraction patterns, which carry the information about the crystal orientation, , crystal defects etc. In transmission electron microscopy (TEM), the most frequent technique related to the electron diffraction is selected area diffraction allowing to measure crystal properties or reconstruct its structure. Despite the technique was considered qualitative for a long time, thanks to modern analytical software it offers quantitative analysis. In scanning electron microscopy (SEM), electron backscatter diffraction is used to determine crystal orientation across the sample. The potential of electron diffraction is not only limited to solids. It can be used to characterize individual molecules dispersed in a gaseous atmosphere using gas electron diffraction. (Wikipedia).
