An investigation was made of almost defect-free (111) c(2 x 8) structures with isolated features such as point and line defects. Clear signs of charge transfer blocking, possibly due to group-III element (probably Ga) substitution, were detected. Deviations of the contrast pattern for an adatom void, as compared with published images, were attributed to H saturation of the exposed dangling bonds in previous experiments. Typical line defects in the (111) (2 x 8) reconstruction, such as a 2 x 2 fault, were suggested to lead to anomalous features of local charge transfer. Localized defect structures, with an approximate size of 16 x 16, were observed. These had some similarity to Si dimer-adatom stacking fault structures. A new type of minority reconstruction, (111)-(8 x 8), was observed over extended areas within large c(2 x 8) reconstructed regions.

P.Molinàs-Mata, J.Zegenhagen: Surface Science, 1993, 281[1], 10-20