Junction lines of inversion domain boundaries with stacking faults in GaN

Abstract

Structural transformations of ${10\overline{1}0}$ inversion domain boundaries (IDBs) are induced by their interactions with basal stacking faults (SFs) in epitaxially grown GaN films. The admissible line defects at the IDB-SF junction lines are edge and mixed type partial dislocations that are often associated with steps of the IDB plane. These interactions have been analyzed at the atomic scale using large scale empirical potential calculations. The majority of the core structures possess either dangling or highly strained bonds. Twenty-eight stable junction line configurations have been identified, 16 of them resulting in stable transformations of the energetically favorable $\mathrm{IDB}*$ type IDB to the electrically active Holt type. The calculated energies and core configurations of the junction lines are discussed in relevance to their combined dislocation and step character. The calculated models have been compared through image simulation with high resolution transmission electron microscopy observations and have been found in good agreement.