Observation of planar defects by reflection electron microscopy

Abstract

The intersections of planar defects with crystal surfaces are studied by reflection electron microscopy. Two types of contrast may be involved in imaging of the intersections of planar defects with crystal surfaces. The first type of contrast is diffraction contrast. It originates from the difference of the diffraction conditions of the two parts on either side of the fault, or from lattice distortions associated with the strain fields in the vicinity of planar defects, such as twin boundaries. This type of contrast is observed and discussed for the 90° ferroelectric domain boundaries (twin boundaries in fact) in BaTiO₃ single crystals. The second type of contrast is the phase contrast produced by the surface steps associated with the defects such as stacking faults and slip faults. Examples of stacking faults on as-grown surfaces of Au spheres are discussed.