Transmission electron microscopy was used to observe Al segregation around threading dislocations in Al0.1Ga0.9N and Al0.3Ga0.7N samples which had been grown by metalorganic chemical vapor deposition onto 6H–SiC. Dislocation lines were found to have a higher Al concentration (by up to 70%) than that of matrix regions which were free of dislocations. The Al-depleted regions around the dislocations were shown to be within a few nm of the dislocation lines. The results also showed that more Al segregated to edge dislocations than to screw dislocations.

Observations of Al Segregation around Dislocations in AlGaN. L.Chang, S.K.Lai, F.R.Chen, J.J.Kai: Applied Physics Letters, 2001, 79[7], 928-30