Weak-beam dark-field electron-tomography of dislocations in GaN

By combining weak-beam dark-field imaging with tomography, we have been able to reconstruct the three-dimensional structure of dislocation arrays in GaN. With a mixture of both threading and in-plane. dislocations, owing to plastic relaxation of the film, we look at how well each dislocation is reconstrucaed and what limits are imposed by way of dislocation density and material anisotropy.