Anisotropic interaction of Ag-induced missing dimer vacancies on Si(001) surfaces

Scanning tunneling microscopy study of Au growth on Ge(001): Bulk migration, self-organization, and clustering

“…Single and double dimer vacancies (DVs) along with (2 + 1) DV complexes (a single DV followed by a normal dimer and then a double DV) can be seen. The increased defect density is attributed to Au diffusion into the Ge substrate [11]; similar phenomena have been observed for other metal contaminated semiconductor surfaces, such as Ni-or Ag-doped Si(0 0 1) [19][20][21][22], and Pt-or Pdcontaminated Ge(0 0 1) [7,23,24].…”

“…The STM image in Fig. 5(c) obtained after annealing a chain-covered surface to 1000 K shows the bare surface dimer row reconstruction with numerous vacancies, typical of metal contaminated semiconductor surfaces [19][20][21][22]39]. This suggests that the Au migrated into the bulk rather than sublimed from the surface at high temperatures.…”

Comparative study of dimer-vacancies and dimer-vacancy lines on Si() and Ge()

“…While such effects could be considered small, note from Table 3 that they systematically lead to a lowering of the formation energy of vacancy lines below the estimate given by (13). As seen in the next section, the DVs are more stable as part of a vacancy line than as members of a bound pair, which is due to the presence of interactions with higher-order neighbors.…”

“…To lower the number of dangling bonds at the surface, the second-layer atoms below the dimer vacancy rebond such that they are fully coordinated, at the cost of introducing some surface stress [21,22,23]. Depending on the preparation details of the surface, other types of atomic structures of VLs can be obtained [8,12,13,14,15,24,25,26]. In this section we focus on the general features of the energetics of the 2 × N surface, without reference to a specific atomic structure.…”

“…2. The choice of these structures is motivated by the experimental observations of the atomic-scale details of vacancy lines on different surfaces: the 1-DV structure is present on Ge-covered Si(001) [8,21,22,23], while lines with the 2-DV and 1+2-DV configurations have been observed on Si(001) with Ni [14,15] and Ag [13] impurities, as well as on radiation-quenched Si(001) [24,25].…”