Relaxation mechanisms in strained nanoislands.

The new mechanism for relaxation of misfit stresses in nanoislands (quantum dots) is suggested and theoretically examined which is the formation of partial misfit dislocations. The parameters of nanoislands are estimated at which the generation of partial misfit dislocations is energetically favorable, with emphasis on the case of Ge/Si nanoislands. Different dislocation structures are shown to be energetically preferred in different regions of the interface.