Surface reconstructions in the Ag/Si(111) system

Identification of the basic structure of the Ag/Si(111)-(6×1)surface: Observation of a low-temperaturec(12×2)phase

“…This Si͑111͒-(3ϫ1) surface is formed by various adsorbates, e.g., alkali metals, alkaline-earth metals, rareearth metals ͑Sm and Yb͒, and Ag with a coverage of 1/3 ML. Although some of the adsorbates actually show different diffraction patterns, e.g., Ag shows a (6ϫ1) pattern, 2,3 all reconstructed surfaces are widely believed to have a quite similar structure based on the similarity of the low-energy electron diffraction ͑LEED͒ I-V curves, 4,5 scanningtunneling-microscopy ͑STM͒ images, [6][7][8][9] and surface corelevel shift ͑SCLS͒ measurements. 8,10,11 The atomic geometry of metal-adsorbed Si͑111͒-(3ϫ1) surface has been studied using a vast number of experimental and theoretical methods, and several structural models have been proposed.…”

Ge Growth on Partially and Entirely Ag Covered Si(111)

“…2 (b) is a superposition of a 5×5 reconstruction and a 3×1 superstructure. Whereas the former is attributed to bare Ge on Si(111), the latter is known to be a low-coverage Ag phase both on Si(111) [26] as well as on Ge(111) [29][30][31]. Since the 3×1 unit cell does not have a threefold symmetry, three different rotational domains appear, as can be seen, e. g., from the indexed third-order spots in Fig.…”

“…Since no other contributions can be found in the LEED pattern, it is concluded that under the adsorption conditions used here, no additional surface phases, in particular no lower-coverage reconstructions [26] like Ag:Si(111)-3×1 are formed. Hence, for the conditions used here, it is possible to use Ag to prepare a chemically modulated surface.…”

“…This implies that the edges of the Ge 3D islands provide a preferential direction for the 3×1 domains and thus breaks the symmetry of the system which usually shows a random arrangement of 3×1 domains on a smooth surface [27]. The main structural feature of the Ag:Si(111)-3×1 reconstruction are chains along the 110 direction [26]. Since the directions in real space (LEEM images) are rotated by about 90…”

Anisotropy of Ag Diffusion on Vicinal Si Surfaces

“…As long as the coverage is above a critical coverage, a particular Ag-induced reconstruction (the specifics of which depend on the sur- * This paper was presented at 10th International Conference on Atomically Controlled Surfaces, Interfaces and Nanostructures (ACSIN-10), Granada Conference Centre, Spain, 21-25 September, 2009. † Corresponding author: simon.sindermann@uni-due.de ‡ Corresponding author: meyerzh@uni-due.de face orientation) is formed [12][13][14]. Further away from the island, the coverage is smaller than the critical coverage for forming the same Ag-induced reconstruction that is present in the direct vicinity of the island.…”