Trace analysis of non-basal plane misfit stress relaxation in (202¯1) and (303¯1¯) semipolar InGaN/GaN heterostructures

We have studied primary and secondary slip systems in the relaxation of lattice mismatch stresses in (202¯1) and (303¯1¯) semipolar InxGa1−xN/GaN heterostructures by analyzing the geometry of traces associated with dislocations employing cathodoluminescence, x-ray diffraction, and transmission electron microscopy. For (202¯1) InxGa1−xN/GaN heterostructures, the primary relaxation is by dislocation glide on the c-plane 112¯0(0001) slip system and secondary relaxation is by dislocation glide on inclined planes including the m-plane 〈112¯0〉{11¯00} slip system. For (303¯1¯) grown heterostructures non-basal slip, namely dislocation glide on the m-plane slip system, is the initial stress relaxation pathway.