Glide of Misfit Dislocations through Multi-Layer Heterostructures

The formation of a misfit dislocation from a half circular dislocation loop originating at the (001) epitaxial surface in a strained layer and in a superlattice heterostructure is considered theoretically. Two steps are considered: the transformation of the dislocation loop into a straight dislocation at the interface between the strained layer and the superlattices and the glide of this interfacial dislocation through the superlattices towards the substrate. The criterion of whether such a mechanism will operate is that, for the first step, the change to the system energy should be minimised, and for the second step, a mechanism should be available to overcome the energy barrier caused by the periodic strain.