On the origin of resonance features in reflectance difference data of silicon

RAS investigation of benzene adsorption on vicinal singledomain Si(001)‐(2 × 1) surfaces

“…The clean silicon signal is similar in shape and in intensity to spectra obtained previously by different authors [3] [7] [6]. The structures at 4.4 eV and 3.35 eV, correspond to surface modified bulk optical transitions at the E 2 critical point and at E 1 and E 0 critical points respectively [11] [26]. These structures seem to be sensitive to the stress of the surface induced by the presence of dimers or/and steps at the surface as it has been demonstrated by Hingerl et al [26].…”

“…The structures at 4.4 eV and 3.35 eV, correspond to surface modified bulk optical transitions at the E 2 critical point and at E 1 and E 0 critical points respectively [11] [26]. These structures seem to be sensitive to the stress of the surface induced by the presence of dimers or/and steps at the surface as it has been demonstrated by Hingerl et al [26]. For lower energies, calculations show that the optical anisotropy observed is attributed to surface-state related transitions [11].…”

Investigation of molecule chemisorption on Si(001)2 × 1 surfaces by surface reflectance spectroscopies

“…Consequently, spectrum (a) displays only (or mainly) the contribution of the transitions involving the DB electronic states, and can be viewed as the optical fingerprint of the adsorption on the dangling bonds. No sharp feature at the critical point (CP) energies of silicon (3.4 eV and 4.3 eV) is present in the spectrum, which is the indication that no surface-modified bulk transition is involved [19]. As for the di-H surface, all dimers are broken and the 2 × 1 reconstruction is removed.…”

“…4(d), and is the optical fingerprint of the dimer breaking, which originates both from suppression of surface transitions involving specific electronic states of the Si-Si dimers, and from suppression of surface-modified bulk transitions due to This spectrum can be viewed as a broad positive feature, extending from about 3 eV to 4.5 eV, superimposed with a sharp negative one located close to the energy 3.4 eV of the E 0 -E′ 1 CP, which gives the observed minimum. This minimum is therefore most likely related to bulk transitions which are modified in the vicinity of the 2 × 1-recontructed surface, because of surface stress related to reconstruction, dimerization and presence of steps [19]. This approach provides a phenomenological tool which permits us to discriminate between the adsorption on the Si dangling bonds (Fig.…”

Optical reflectance anisotropy of buried Fe nanostructures on vicinal W(110)

“…This is equivalent to a ∂ε/∂ω shape of the dielectric anisotropy which is frequently found for RAS spectra dominated by modified bulk states [23,24]. Strain induced RAS has been investigated extensively in semiconductors and can be related to the piezoelectric tensor of the material [25,26]. For metals, the simple approximation described above has been used successfully to model the anisotropy of other metal surfaces dominated by bulk modifications [27] and this approach will be used here.…”