Microscopic dislocation structures in wurtzite-type GaN crystal were studied by the use of molecular dynamics simulation. Parameters for a 2-body interatomic potential were determined by using the Hartree-Fock ab initio method. A dislocation was generated by the coalescence of the facing planes of a semi-infinite trench structure in the crystal. Six types of trench structure, with different depth-directions and extension-directions, were examined at 1000 and 1500K. A core structure with an 8-fold ring was confirmed for edge dislocations along the c-axis, although there appeared to be a few atoms that were shifted from the ring core structure. The latter structure was consistent with reported theoretical expectations and experimental observations. A 10-fold ring core structure was also observed for edge dislocations along the c-axis. A screw dislocation was generated by an attracting force between Ga and N atoms across the trench space, when the attracting force had a large component parallel to the trench extension direction.

Molecular Dynamics Simulation of Dislocations in Wurtzite-Type GaN Crystal. K.Harafuji, T.Tsuchiya, K.Kawamura: Journal of Applied Physics, 2004, 96[5], 2513-24