Convergent beam diffraction studies of interfaces, defects, and multilayers.

ABSTRACT

This paper explains how the convergent beam electron diffraction (CBED) and large angle convergent beam (LACBED) techniques can be used to study crystal defects, bicrystals, and multilayers. It is shown how the LACBED technique in particular can be used to derive the magnitude and sign of the Burgers vectors of dislocations and displacements at stacking faults. For bicrystals and multilayers examined in plan-view, LACBED gives the rocking curve for a chosen reflection. This enables layer strains to be measured to approximately 0.1% and composition profiles derived for both periodic and aperiodic structures. It is shown that a simple kinematic approach can be used to interpret the essential results in most cases.