SAED works by focusing a coherent electron beam onto a small, selected area of a thin sample. When the electrons interact with the crystalline structure of the sample, they are diffracted, creating a pattern of spots. This diffraction pattern is recorded on a detector and can be analyzed to determine the lattice parameters and symmetry of the crystal. The selected area aperture in the TEM allows for isolation of the specific region of interest, making SAED an invaluable tool for localized structural analysis.
