High-Resolution Three-Dimensional Imaging of Dislocations
J. S. Barnard,*
J. Sharp,
J. R. Tong,
P. A. Midgley*
Dislocations and their interactions govern the properties of
many materials, ranging from work hardening in metals to device
pathology in semiconductor laser diodes. However, conventional
electron micrographs are simply two-dimensional projections
of three-dimensional (3D) structures, and even stereo microscopy
cannot reveal the true 3D complexity of defect structures. Here,
we describe an electron tomographic method that yields 3D reconstructions
of dislocation networks with a spatial resolution three orders
of magnitude better than previous work. We illustrate the method's
success with a study of dislocations in a GaN epilayer, where
dislocation densities of 1010 per square centimeter are common.
* To whom correspondence should be addressed. E-mail: pam33{at}cam.ac.uk (P.A.M.); jsb43{at}cam.ac.uk (J.S.B.)
