Interfacial structure of a -plane GaN grown on r -plane sapphire

The interface between a -plane GaN, grown by metal organic vapor phase epitaxy and hydride vapor phase epitaxy, and r -plane sapphire was investigated by transmission electron microscopy in [1-100] and [0001] zone axis orientations. The interfacial structure was well defined allowing a direct observation of the misfit dislocations in both orientations. An analysis of these dislocations revealed for the respective Burgers vectors a 13 <2-1-10> component in the {0002} planes and a 12 <0001> component in the {1-100} planes. In addition, the relative atomic column configurations in the GaN and sapphire were determined based on Bloch-wave simulations in comparison with the experimental images. © 2007 American Institute of Physics.