Lattice defect identification using convergent-beam electron diffraction
Electron microscopy has made a great success in the identification of lattice defects. Convergent-beam electron diffraction (CBED) also allows us to identify them and CBED gives more information about lattice defects than the electron- microscope-image method. Lattice defects are divided into two basic types. One causes a phase shift at the defect and the other an angular change. The stacking fault is a typical example of the former type and the coherent twin boundary, of the latter type. The dislocation can be treated as an extension of the former type. CBED can determine the displacement vector of a stacking fault, the Burgers vector of a dislocation and the orientation difference at a coherent twin boundary reliably and easily. We will explain the methods to determine them using examples. STACKING FAULTS : Rocking curves obtained from a stacking fault are different from those of a perfect region in a manner characteristic of the displacement between two crystals at the fault.