On the atomic structure of periodic [0001] tilt boundaries in GaN:: dislocations mobility and boundary-dislocation interaction

We have investigated the mobility of the crystal dislocations and their interaction with certain tilt boundaries in GaN by means of atomic computer simulation. Among the three possible stable cores of the 1/3 [2, (1) over bar, (1) over bar, 0] (a-type) edge prism dislocation, namely, C-5/7, C-4 and C-8, it was found that the C-4 and C-8 cores move under an applied strain whereas the C-5/7 core is sessile. The a edge basal, a screw and c dislocations are not mobile under strains up to 5%. The simulation also shows that a C-4 or C-8 units at the interface of certain tilt boundaries move under an applied strain. In turn, dislocations can either annihilate or incorporate on these boundaries. (C) 2003 Elsevier B.V. All rights reserved.