Dimer-adatom-stacking

Figure 5.5. Dimer-adatom-stacking fault (DAS) model of the Si(lll)-7x7 surface unit cell by Takayanagi et al. [44]. Figure reused with permission from Ref. [46], Y. Cao, Journal of Chemical Physics, 115, 3287 (2001). Copyright 2001, American Institute of Physics.

It is now generally accepted that the correct structural characterization of the complex Si(lll) (7x7) structure is the dimer-adatom stacking fault model proposed by Takayanagi and coworkers (Takayanagi et al., 1985a, b). This structure consists of twelve Si adatoms located upon of a layer of Si dimers with vacancies at the vertices of the (7x7) unit cell. The physical origin of the tendency of this surface to form such a complex reconstruction is believed to be the result of the competition between two factors the... 

Table 5.2-5 Reconstruction and relaxation of semiconductors. IB A, ion bombardment and annealing MBE, molecular-beam epitaxy DAS, dimer-adatom-stacking fault. References are given in [2.3]...

Figure 9.27 Dimer-adatom-stacking fault (DAS) model of the Si(l 11 )-(7x 7) reconstruction. Each of the 12 adatoms with almost empty dangling bonds in the first layer saturate three top atoms in the second layer. The top atoms are arranged in a local (2x2) subunit. The dangling bond orbits of the adatoms are the dominant features observed in scanning tunneling microscopy. The remaining six rest atoms in the second layer...

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