Luisa Ferrari

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Papers by Luisa Ferrari

Sharp high-resolution Si2pcore level on the Sb-terminated Si(111) surface: Evidence for charge transfer

Physical Review B, 2000

An Sb/Si͑111͒)ϫ) surface has been studied by high-resolution core-level spectroscopy. All the com... more An Sb/Si͑111͒)ϫ) surface has been studied by high-resolution core-level spectroscopy. All the components of the Si 2p core level related to the clean surface have disappeared, and one strong Sb-induced component could be identified at a binding energy ϩ0.13 eV with respect to the bulk peak. Such a component is mainly due to charge transfer between Si atoms at the top layer and Sb trimers. Two more small components are observed: one at ϩ0.29 eV, due to Sb atoms residing at a different position, and one at Ϫ0.14 eV, due to local disorder. On the Si 2p core level taken in bulk sensitive mode, we found a very narrow bulk component with a total full width at half maximum of 140 meV at Tϭ100 K.

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Exciton states in In x Ga1−x As/GaAs double quantum wells: Normalized reflection spectra

Il Nuovo Cimento D, 1995

Summary Normalized reflection spectra in GaInAs/GaAs quantum wells are shown for two sets of sam... more Summary Normalized reflection spectra in GaInAs/GaAs quantum wells are shown for two sets of samples with different alloy concentration (x=9% and 18.5%) and well thickness ranging from 1.5 nm to 25 nm. All samples were grown on (001) GaAs surface by Molecular Beam Epitaxy and characterized by RHEED and X-ray reflection diffraction. Exciton envelope function in effective mass approximation and optical

Electronic properties and photoelectron circular dichroism of adsorbed chiral molecules

Physical Review B, 2015

We report on an angle-resolved photoemission investigation of the valence states and chiral prope... more We report on an angle-resolved photoemission investigation of the valence states and chiral properties of a nonchirally oriented phase of tartaric acid deposited on a Cu(110) surface, observed with circularly polarized light. The two optical enantiomers R,R and S,S of tartaric acid, separately deposited, produce (40,23) overlayers which show a large dichroic effect and enantiomeric behavior all over the valence energies. The dichroic effects are displayed by native chiral molecular states and molecule-copper interface states. Density-functional theory calculations of the site-resolved density of states analyze the formation of hybrid states at the tartaric acid-copper interface and suggest that an observed interface state acquires chirality on binding.

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Island formation in Sb films deposited at room temperature on Si(100)2×1 surfaces

Physical Review B, 1993

The early stages of Sb films deposited at room temperature on Si(100)2×1 surfaces have been inves... more The early stages of Sb films deposited at room temperature on Si(100)2×1 surfaces have been investigated by angle-integrated and angle-resolved Auger spectroscopy. A comparison between the experimental results and the predictions of simple deposition models indicates that the growth of the Sb film proceeds by island formation. Without any annealing, a uniform overlayer never develops up to films 4 nm

Scanning Tunneling Microscopy

Strong correlation effects in the electronic structure of Sr2FeMoO6

Physical Review B, 2003

We investigate the electronic structure of Sr 2 FeMoO 6 combining photoemission spectroscopy with... more

Luminescence and Franz-Keldish effect on CdTe(110)1 × 1 surfaces by surface differential reflectivity

Vacuum, 1995

We present data on photoluminescence (PL) and the Franz-Keldish (FK) effect on ultra high vacuum ... more We present data on photoluminescence (PL) and the Franz-Keldish (FK) effect on ultra high vacuum cleaved CdTe(110) 1 × 1 surfaces by surface differential reflectivity (SDR). PL and FK effects on the clean surface have been studied as a function of an argon laser power with the sample at room temperature. PL spectra have been divided into two contributions: a

Polarized surface differential reflectivity and oxygen chemisorption on InP(110) surfaces

Surface Science, 1991

ABSTRACT We present surface differential reflectivity (SDR) results on the polarization dependenc... more ABSTRACT We present surface differential reflectivity (SDR) results on the polarization dependence of optical transitions and on the oxidation of InP(110) surfaces in the energy range between 2.0 and 4.0 eV. The surface dielectric function has been derived for the light electric vector along [110] and [001] directions. The data show two anisotropic peaks at 2.6 eV (excited with the light electric vector along the [110] direction) and 3.5 eV (excited with the light electric vector along the [001] direction) and an almost isotropic behaviour for the peak at 3.1 eV. Absorption kinetics is analyzed by following the reflectivity variation between 1 × 102 and 2 × 106 langmuirs of molecular oxygen at three selected spectral energies. Several well-defined steps of the oxidation process are clearly resolved and discussed in terms of disappearance of intrinsic surface states, creation of acceptor and donor defect states, and growth of In2O3. © 1991.

High resolution photoemission core level spectroscopy study and TEM analysis of the Ge/As/Si(001) growth

Surface Science, 2001

The deposition of 1 ML of As on Si(001)-(2×1) surface and the heteroepitaxial Ge/As/Si(001)-(2×1)... more The deposition of 1 ML of As on Si(001)-(2×1) surface and the heteroepitaxial Ge/As/Si(001)-(2×1) growth were studied by using high resolution core-level spectroscopy and transmission electron microscopy (TEM). From the spectral decomposition of the Si2p core levels, collected on the Ge/Si interfaces obtained by codepositing As and Ge atoms at different Ge thickness, we identify the contribution of different Si

SiC(111) growth by C60 decomposition on Si(111) studied by electron spectroscopies

Surface Science, 2001

ABSTRACT We have grown an ordered SiC(1 1 1) film, characterized by a (1×1) low energy electron d... more ABSTRACT We have grown an ordered SiC(1 1 1) film, characterized by a (1×1) low energy electron diffraction (LEED) pattern, by evaporating C60 molecules on a Si(1 1 1) substrate kept at 1200 K in ultrahigh vacuum conditions. In situ inverse photoemission spectra show the presence of a state at the conduction band minimum attributed to C–Si bond, whose intensity has been found to be related to the morphology of the grown film.We studied ex situ LEED, Si 2p and valence band photoemission spectra of the same SiC(1 1 1) sample as introduced in the vacuum chamber and after a sputtering/annealing treatment. After the cleaning procedure LEED shows clearly the recovering of the (1×1) pattern and the valence band spectra show the expected line shape for the SiC(1 1 1)-(1×1) sample. Evolution of the electronic configuration of the samples after Si evaporation will be discussed.