Structural transition of inversion domain boundaries through interactions with stacking faults in epitaxial GaN

In epitaxial wurtzite GaN, structural transformations of inversion domain boundaries on prismatic planes are observed at their intersections with stacking faults on the basal plane. High resolution electron microscopy observations show that, following the growth direction, the inversion domain boundaries are transformed from the low-energy and electrically nonactive IDB* type to the high-energy, electrically active, Holt-type structure. By using the topological theory of interfacial defects, it is proved that these transitions are due to the interaction of two distinct planar defects, and can be attributed to the different growth rates of adjacent domains of inverse polarity. The junction lines of the planar defects are characterized by employing the circuit mapping technique as formulated mathematically for multicomponent crystal systems. It is found that these lines exhibit partial dislocation character and an analytical account of such lines is presented.