Crystals grown by molecular-beam epitaxy, onto (00•1) sapphire, exhibited [00•1] tilt boundaries with low and high angles. The structure of the boundaries played a role in opto-electrical properties. The atomic structure of Σ7, Σ13 and Σ19 boundaries were studied here by means of atomic computer simulations, using a modified version of the empirical Stillinger-Weber interatomic potential. For each Σ boundary, the interface of lowest period was studied and the atomic structure of minimum energy was found by applying the method of quasi-dynamic relaxation. Special attention was paid to the Σ13 boundary, where 2 different interfaces were studied by comparing the present results with the published results of a study of ZnO bicrystals. In these boundaries, the atomic structure could be understood in terms of edge dislocations located along the boundary.

Atomic Structure of [0001] Tilt Boundaries in GaN. A.Béré, A.Serra: Interface Science, 2001, 9[3-4], 149-55