Search

Optical transitions between surface state bands have been detected on the Si(111)-Pb(√3 × √3) mosaic phase by means of surface differential reflectivity (SDR) in the energy range between 1.3 and 3.8 eV. The SDR spectrum, obtained between the clean and the hydrogenated surface, presents a broad structure in this energy range with a maximum at 3.0 eV. The spectrum has been deconvolved into three Gaussian singlets at energies 1.8, 2.5 and 3.05 eV. These transitions have been, tentatively, assigned to different points in the surface Brillouin zone. No contribution from the hydrogenated surface is expected, as observed by angle resolved photoemission.

Surface differential reflectivity experiments with polarised light have been carried out for cleaved and then oxidised CdTe(110) surfaces. It was shown that the optical anisotropy of the surface investigated is small and almost independent from photon energy. The interpretation of the spectra in terms of optical transitions between surface states is discussed.

New accurate surface differential reflectivity data of the GaAs and GaP cleavage faces are presented. Surface state transitions have been detected near 2.9 eV in GaAs(110), while in GaP(110) they appear at 2.8 and 3.5 eV. In both cases a small bulk-like Franz-Keldish effect is superimposed on the surface contribution to differential reflectivity. A method for subtracting this term out is described. The relevance of the present results in the context of the debate on surface excitons is also discussed.

We compute the optical properties of semiconductor surfaces starting from the self-consistent electronic structures determined using local pseudopotentials with a plane-wave basis set. Calculations for a 9 layer (110) slab of GaP are carried out with both clean and H covered surfaces. Differential reflectivity spectra and their anisotropies are interpreted in terms of transitions involving surface states.

The optical properties of the GaAs(110) surface are studied by means of self-consistent local-density slab calculations. It is found that a large contribution to the calculated anisotropy of the clean surface reflectance is related to transitions which do not involve surface states. Comparison is made with differential reflectivity and reflectance anisotropy experiments.

We present a determination of surface dielectric functions (SDF) of Si(111)2×1, Ge(111)2×1, GaAs(110) and GaP(110) surfaces obtained using polarized surface differential reflectivity (SDR) technique.