The symmetry of convergent-beam electron diffraction patterns from bicrystals containing a vertical grain boundary

Abstract

In this paper an analysis is presented of the possible symmetries of convergent-beam electron diffraction (CBED) patterns taken from bicrystals with the incident electron beam parallel to the grain boundary. By establishing the connection between CBED symmetry and the possible point groups of a bicrystal, useful information on the grain boundary structure is obtained. This is illustrated by experiments on a vertical (111) twin boundary in silicon. It is shown that a complete symmetry determination from such a twin boundary is possible only if the double-rocking technique for Obtaining zone-axis patterns is employed.