Experimental studies of the dangling- and dimer-bond-related surface electron bands on Si(100) (2×1)

Abstract

Angle-resolved ultraviolet photoelectron spectroscopy has been used to determine the initial-state energy versus k~~dispersion of surface states on the Si(100) (2X 1), twodomain, reconstructed surface. One surface state was found at 0.70 eV below EF at the I symmetry point. The energy dispersion relation for this surface state was measured along the I -J, I -J', and J -K symmetry lines of the (2& 1) surface Brillouin zone (SBZ). A second surface state was observed in the energy range between 2 and 3 eV below EF. The energy dispersion relation for this surface state was obtained along the J -E symmetry line of the SBZ and in the [010] bulk azimuthal direction. The experimentally obtained dispersion relations are compared with the surface electron bands as given by a tightbinding calculation of the asymmetric dimer model. The experiment gives a surface-state band whose center of gravity is in good agreement with the calculation, while the bandwidth is approximately half as large as the calculated. For the lower surface state both initial energy position and dispersion are in good agreement with the calculation. The upper surface state is assigned to a dangling-bond band and the lower is tentatively assigned to the dimer bond.

Adsorption of atomic oxygen (N2O) on a clean Si(100) surface and its influence on the surface state density; a comparison with O2

“…[48]) but no calculations exist so far for a model involving buckled as well as nonbuckled dimers and single and multiple dimer defects. Such a model would be in accordance with the results from the STM study [9] and might also give an explanation for the existence of two filled surface states [17,47,48,503 and for the observed two minima in the almost empty surface state band [48]. The authors of the STM study [9] have argued that the ratio of buckled to nonbuckled dimers and the density of single and multiple missing dimer defects depend on the exact preparation of the clean surface and on remaining surface impurities.…”

“…Peak Bl, which has its maximum at hv = 1.60 eV ( fig. 7), may therefore be attributed to optical transitions from a filled dangling bond surface states band at -1.3 eV below E, [17,47,48,50] (DBdX2) which corresponds to c(4 X 2) and/or 2 X 2 reconstructions, to the empty surface states band at -0.4 eV above E, [27,49,58]. Peak Al (figs.…”

Epitaxial Growth of Large Pentacene Crystals on Si(001) Surfaces Functionalized with Molecular Monolayers

“…The peak at 0.6 eV has been attributed to the dimer reconstruction at the surface. 45 Figure 2b, a spectrum taken after exposing the same sample to 20 L COD, shows the disappearance of the Si dimer peak and the appearance of peaks at 1.8 (shoulder), 3.8, and 6.2 eV. The peak at 6.2 eV is in the region (5-10 eV) that is characteristic of C-C single bonds and thus is due to the COD molecule.…”

Cycloaddition reaction of furan with Si(100)-2×1

“…Since then a great deal of theoretical and experimental work has proven the existence of buckling dimers. [33][34][35] For the ground state the concept of buckling dimers is now prevailing and conclusive. At room temperature, the SivSi dimers do not generally display asymmetry in their STM images.…”