Backscatter Kikuchi diffraction in the SEM for identification of crystallographic point groups

A preliminary account is given of the application of backscatter Kikuchi diffraction patterns (BKP) to point group determination in the SEM. Studies carried out on bulk specimens selected from the 32‐point groups indicate that 27 of the 32‐point groups can be determined unambiguously using BKPs, though distinction between 6,6,4,4 and 3 and 3 is difficult and requires special procedures. Evidence for breakdown of Friedel's law was observed in BKPs from GaSb, thus confirming the noncentrosymmetric point group 43m. Differences in intensities observed between the reflections hkl and hk̄l̄ reflections in GaSb which arise from the sensitivity of dynamical interactions to phases of the structure factors, could not be found in GaAs, illustrating that point group determination using BKPs should be considered with caution.