ASYMMETRIC TILT INTERFACE INDUCED BY 60-DEGREES MISFIT DISLOCATION ARRAYS IN GASB GAAS(001)

Transmission electron microscopy of GaSb film grown on (001) GaAs revealed regular 60°misfit dislocation arrays in abnormally large and irregularly shaped GaSb islands. Having a same orientation of the Burgers vector, the 60°dislocations induce an asymmetric tilt interface. Calculations using anisotropic elasticity show that this interface has lower elastic energy than the symmetric interface relaxed by 60°dislocations of alternating orientations. When 60°dislocations are generated at the leading edge of growing islands, a particular orientation that assists the bending of atomic planes to the free surface of islands is preferred for a partial elastic relief of the misfit strain. © 1994 American Institute of Physics.