BURGERS VECTOR DETERMINATION IN TEM BY USING THE DISLOCATION PARITY ANALYSIS

A modified method of identifying the Burgers vector b is proposed, whi ch is based on the extended analysis of dislocation contrast features. High voltage electron microscopy (HVEM) as well as the computer simul ation of the electron micrographs are applied to study the contrast be haviour of mixed dislocations with a large screw component of the Burg ers vector under different diffraction conditions in order to check th e validity of the method proposed. The analysis of the contrast oscill ations along inclined dislocations or the image shift relative to the projection of the dislocation line enables us to determine the 'disloc ation parity' P = sgn (l x b . B) while the halo contrast can be used to define the orientation of the 'additional half plane', which is cha racterized by the normal e = l x b/\l x b\ to the glide plane. The par ity and sgn (g . e) analysis enables the unambiguous b vector determin ation whenever solely one invisibility criterion is applicable. The di slocation parameters in heterostructures are investigated by the above method.