A scanning tunnelling microscopic investigation was made of the defects which were produced by small amounts of Ga on the c(2 x 8) (111) Ge surface. The surfaces were prepared either by using Ga-doped crystals (with a concentration of up to 1019/cm3 or by depositing up to 0.05 of a monolayer of Ga. Each surface area was studied in the constant-current mode for 2 different bias values; thus providing electronic and structural information for each defect. The Ga atoms were found to preserve the c(2 x 8) reconstruction. The defects included those in which adatoms occupied H3 sites, as well as those which broke the c(2 x 8) long-range order.

P.Molinàs-Mata, J.Zegenhagen: Physical Review B, 1993, 47[16], 10319-25