Formation mechanism and relative stability of the {11(2)over-bar-0} stacking fault atomic configurations in wurtzite (Al,Ga,In) nitrides

The formation of the (1 (2) over bar 10) stacking fault, which has two atomic configurations in wurtzite (Ga,Al,In)N, has been investigated by high-resolution electron microscopy and energetic calculations. It originates from steps at the SiC surface and it can form on a flat (0001) sapphire surface. A modified Stillinger-Weber potential is used in order to investigate the relative stability of the two atomic configurations which have comparable energy in AIN, whereas the 1/2[10 (1) over bar 1]{1 (2) over bar 10}atomic configuration should be more stable in GaN and InN. Experimental evidence is shown in the case of AW and GaN from high-resolution electron microscopy. Observations carried out in plan-view show the 1/2[10 (1) over bar 1]{1 (2) over bar 10} atomic configuration in GaN layers. The 1/6[20 (2) over bar 3] configuration was found in small areas inside the AIN buffer layer in cross-section observations. It folds rapidly to the basal plane, and when back in the prismatic plane it bears the 1/2[10 (1) over bar 1]{1 (2) over bar 10} atomic configuration.