Scanning tunnelling microscopy and low-energy electron diffraction methods were used to investigate (111) vicinal surfaces which were misoriented by 1 and 2 towards the <11¯2> and <¯1¯12> high-symmetry directions. The surfaces of moderately Ga-doped (1019/cm3) material reconstructed as c(2 x 8). No straight step edges, but meandering kinks between terraces, were observed via scanning tunnelling microscopy. In highly Ga-doped (2 x 1020/cm3) crystals which were rich in dislocations and Ga inclusions, the vicinal surfaces exhibited a previously reported room-temperature low-energy electron diffraction pattern, for a well-oriented clean Ge(111) surface, which appeared at about 300C. Room-temperature scanning tunnelling microscopic images clearly revealed the incommensurate honeycomb-domain reconstruction, I(2 x 2), which had been proposed in order to explain the low-energy electron diffraction pattern. A high dislocation density and misorientation appeared to be essential in order to observe this reconstruction. This was thought to be the first real-space observation of such a structure.

P.Molinàs-Mata, J.Zegenhagen, A.Höpner, H.Bender, E.Schönherr, H.Labitzke: Journal of Physics - Condensed Matter, 1993, 5[46], 4687-94