Chemisorption and thermally activated etching of Si(100)-2×1 by iodine

Bromine adsorption on Ge(001) surface: comparative study for coverages of 0.25, 0.5, 0.75 and 1 monolayer

“…Bromine atoms adsorbed at the same side of germanium dimers form chains of bright spots in simulated images. Similar STM features of the form of long chains are seen in experimental images [1]. Moreover, as follows from our simulations, slight differences in the height of adatoms (above the surface) from parallel chains result in noticeable changes in intensities of protrusions observed in STM images (see configuration C in Fig.…”

“…1) is the same as the inner structure of two-dimensional iodine islands found at Si(100)-(2×1) after etching (see Fig. 6 in [1]). Bromine atoms adsorbed at the same side of germanium dimers form chains of bright spots in simulated images.…”

“…The only exception is the hexagonal configuration as obtained using the lo method, where adsorbate atoms are placed closer to the substrate (this effect, however, is not found within the pw scheme; see Table 1). Calculations indicate that the p(2×4) configuration with Br adatoms bound to both sides of the same Ge dimer is energetically most favourable, as for other cases of halide adsorption on Ge(001) and Si(001) [1,2,7]. The ordering of local-energy-minimum structures is the same in lo and pw calculations.…”

“…The second configuration is expected to be energetically preferable and therefore observed more often. Depending on the adsorbate coverage, c(2×2) and p(2×1) reconstructions have been observed on Si(001) for 0.5 and 1 monolayer (ML) of iodine respectively [1,2].…”

“…Most of the studies have been concerned with Si and GaAs surfaces (see [1] and references therein). At the (001) surface of Si and Ge, halide molecules dissociate and atoms usually adsorb without breaking the substrate dimer bonds.…”