It was found that films of GaSb which were grown onto (001)GaAs exhibited regular 60° misfit dislocation arrays in abnormally large and irregularly shaped GaSb islands. As they had the same orientation of Burgers vector, the 60° dislocations induced an asymmetrical tilt interface. Calculations which were performed using anisotropic elasticity showed that this interface had a lower elastic energy than the symmetrical interface which was relaxed by 60° dislocations with alternating orientations. When 60° dislocations were generated at the leading edge of growing islands, a particular orientation (which assisted the bending of atomic planes to the free surfaces of islands) was preferred for partial elastic relief of the misfit strain.

J.M.Kang, S.K.Min, A.Rocher: Applied Physics Letters, 1994, 65[23], 2954-6