Identification of Star Defects in Gallium Nitride with HREBSD and ECCI

This paper characterizes novel “star” defects in GaN films grown with metal–organic vapor phase deposition (MOVPE) on GaN substrates with electron channeling contrast imaging (ECCI) and high-resolution electron backscatter diffraction (HREBSD). These defects are hundreds of microns in size and tend to aggregate threading dislocations at their centers. They are the intersection of six nearly ideal low-angle tilt boundaries composed of $\langle a\rangle$-type pyramidal edge dislocations, each on a unique slip system.