A review was presented of the topological theory of defects and interfaces in crystalline materials, aimed at illustrating cases that were studied under this framework in nitride films and interfaces. The review addresses crystallographic calculations in hexagonal and trigonal crystals using the Frank system. It also presents the principal methods of a priori and a posteriori defect characterization in a unified manner, showing their equivalence, the circumstances under which they were applicable, and practical aspects of their deployment. A number of experimental observations were analyzed, and useful conclusions were extracted, for example, concerning admissible defects, structure-mechanism relations, and the influence of defects on properties. These included threading, stacking-fault and interfacial dislocations in GaN epilayers, the influence of the epitaxial interface on the systematic appearance of inversion and stacking disorder, structural transformations of inversion domain boundaries due to their intersections with stacking faults and double-positioning twinning in TiN contact layers deposited on GaN.

Topological Analysis of Defects in Epitaxial Nitride Films and Interfaces. G.P.Dimitrakopulos, P.Komninou, R.C.Pond: Physica Status Solidi B, 2001, 227[1], 45-92