Determining polarity and dislocation core structures at atomic level for epitaxial AlN/(0Â 0Â 0Â 1)6H-SiC from a single image in HRTEM

► A method proposed for determining polarity and defect core structure of AlN. ► The polarity and dislocation core structures were determined from a single image. ► Al and N atomic columns of spacing 0.109 nm were distinguished. ► Atomic configurations of 10- and 12-atom ring were derived at atomic level. ► The method is valid for other binary semiconducting compounds.