A combination of transmission electron microscopy and large-angle convergent beam electron diffraction was used to examine dislocations and nanopipes, and to show that the migration of dislocations in epitaxially overgrown material was related to local shear strains and grain rotations. It was shown that electron holography could be used to examine in-plane electric fields and, in particular, the charge on threading edge dislocations.

TEM Characterisation of Defects, Strains and Local Electric Fields in AlGaN/InGaN/GaN Structures. D.Cherns: Materials Science and Engineering B, 2002, 91-92, 274-9