The formation energy of a structure was usually increased by the appearance of a defect. A stoichiometric planar defect structure of the wurtzite AlN (10•0) surface, however, was found to be lower in energy than the ideally truncated surface by first-principles calculations. The intriguing phenomenon was directly attributed to the large scale surface relaxation induced by the defect structure and the intrinsic reason was pointed to the strong ionicity and small c/a (lattice constant ratio) of AlN. A suggested growth mode showed that the defect surface structure was compatible with the growth of the correct wurtzite AlN film on the (10•0) plane.

Stability of a Planar-Defect Structure of the Wurtzite AlN (10¯10) Surface - Density Functional Study. H.Ye, G.Chen, Y.Wu, Y.Zhu, S.H.Wei: Physical Review B, 2009, 80[3], 033301