As a p-type dopant, Be induced changes in the reconstruction of the GaAs(001) surface. This was studied as a function of Be coverage up to 0.5ML by reflection high-energy electron diffraction and scanning tunnelling microscopy. Under standard molecular beam epitaxy conditions, the reflection high-energy electron diffraction pattern continuously changes with increasing Be coverage from the starting (2 x 4) via a (2 x 3) to a (1 x 2) symmetry. This transition was characterized by a gradual decrease of both, the intensity of the ½-order spots (first in the [110] then in the [110] azimuth) and the spacing of the ¼-order spots (in the [¯110] azimuth). scanning tunnelling microscopy images reveal that the surface was composed of both As and Ga/Be terminated domains. The former reconstruct from (2 x 4) to (2 x 3) units, the latter from (2 x 3) to (1 x 2) units. Electron-counting arguments suggested that the domain type and size were determined by the requirement that the excess electron density was balanced by the acceptor density of the incorporated p-type Be doping.

Reconstruction of the GaAs(001) Surface Induced by Submonolayer Be Deposition. H.Oigawa, M.Wassermeier, J.Behrend, L.Däweritz, K.H.Ploog: Surface Science, 1997, 376[1-3], 185-91