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73 results on '"Gensterblum, G."'

3. High-Resolution Electron Energy Loss Spectroscopy of Thin C60 Films

Author

Gensterblum, G., Pireaux, J. J., Thiry, P. A., Caudano, R., Lambin, Ph., Lucas, A. A., Cardona, Manuel, editor, Fulde, Peter, editor, von Klitzing, Klaus, editor, Queisser, Hans-Joachim, editor, Lotsch, Helmut K. V., editor, Kuzmany, Hans, editor, Mehring, Michael, editor, and Fink, Jörg, editor

Published
1993
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6. Structural defects and epitaxial rotation of C60 and C70(111) films

Author

Bernaerts, D., Tendeloo, G. Van, Amelinckx, S., Hevesi, K., Gensterblum, G., Yu, L.M., Pireaux, J.-J., Grey, F., and Bohr, J.

Subjects
Thin films -- Research, Molecular rotation -- Observations, Carbon allotropes -- Observations, Crystal lattices -- Observations, Physics
Published
1996

9. Vibrational study of C-60 overlayers on H/Si(111)-(1x1)

Author

Dumas, P., Gruyters, M., Rudolf, P., He, Y., Yu, L.-M., Gensterblum, G., Caudano, R., Chabal, Y.J., and Zernike Institute for Advanced Materials

Abstract

We have studied the vibrational properties of thin C60 overlayers deposited on ideally H-terminated Si(111) surfaces, by multiple infrared reflection and high-resolution electron energy-loss spectroscopies. We find that the Si-H interface remains intact upon C60 deposition: the Si-H stretching mode frequency, initially at 2083.8 cm-1, shifts downward to 2062 cm-1, and broadens while keeping the same integrated intensity. Due to the symmetry-breaking effect at the surface on the adsorbed C60 molecules, a new IR band is observed at 1445 cm-1 which is mainly s-polarised. No evidence for chemical interaction between C60 and H/Si(111)-(1 x 1) is found, pointing to van der Waals-type bonding. From the relative intensities of the dipole-active and -inactive modes in HREELS in the specular direction, and from the angular width of the scattered elastic peak, the growth of an ordered film is inferred.

Published
1996

10. Electronic-transitions and excitations in solid C-70 studied by EELS and XPS c-1s satellite structures

Author

Han, Bo-ying, Yu, Li-ming, Hevesi, K., Gensterblum, G., Rudolf, P., Pireaux, J.-J., Thiry, P.A., Caudano, R., Lambin, Ph., Lucas, A.A., Zernike Institute for Advanced Materials, and Surfaces and Thin Films

Subjects
FULLERENE C-70
Abstract

The electronic transition and excitation properties of highly ordered C70 films have been studied by reflection electron-energy-loss spectroscopy (EELS) and x-ray photoemission spectroscopy (XPS) C 1s satellite structures. The EELS study revealed a total of 11 features in the energy-loss range 1–40 eV. These include two tight-binding Frenkel excitonic levels in C70 fullerite, at 1.53 and 1.88 eV; the feature at 2.20 eV correlated with the onset of the electron transitions between the highest occupied molecular-orbital- and lowest occupied molecular-orbital-derived bands; a doublet at around 6 eV showing evidence of the π-plasmon splitting of fullerite C70. A broad hump at ~28 eV corresponds to the excitation of the (σ + π) plasmon. The XPS C 1s satellite structures were found to be in overall agreement with the EELS results in the corresponding energy-loss range. By comparing the EELS data with the direct and inverse photoemission data, the on-site Coulomb correlation energy has been determined to be 1.2±0.2 eV for C70 fullerite.

Published
1995

11. Comment on 'Adsorption of C60 on Ta(110): Photoemission and C K-edge studies'

Author

Rudolf, P., Gensterblum, G., and Zernike Institute for Advanced Materials

Subjects
Fullerene
Abstract

Recently, ultrathin C60 films on a Ta(110) surface were characterized by photoemission and C K-edge studies. It was concluded that some fraction of the fullerene overlayer decomposes on the clean metal surface resulting in a thin layer of carbon between the assembled film and the metal substrate. In this Comment we argue that there is not enough experimental evidence to sustain this interpretation. Those experimental results can be interpreted by a chemisorbed first monolayer without inferring the formation of a thin carbon layer at the interface. Furthermore, that proposed alignment of the C60 π and π* energy levels is not correct.

Published
1994

12. Growth mode and electronic structure of the epitaxial $\mathrm{C_{60}(111)/GeS(001)}$ interface

Author

Gensterblum, G., Hevesi, K., Han, B.-Y., Yu, L.-M., Pireaux, J.-J., Thiry, P. A., Caudano, R., Lucas, A.-A., Bernaerts, D., Amelinckx, S., Van Tendeloo, G., Bendele, G., Buslaps, T., Johnson, R. L., Foss, M., Feidenhans’l, R., and Le Lay, G.

Subjects
ddc:530
Abstract

Physical review / B 50(16), 11981 - 11995 (1994). doi:10.1103/PhysRevB.50.11981, Published by Inst., Woodbury, NY

Published
1994
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14. Structural defects and epitaxial rotation of C-60 and C-70(111) films on GeS(001)

Author

Bernaerts, D., Van Tendeloo, G., Amelinckx, S., Hevesi, K., Gensterblum, G., Yu, L.M., Pireaux, J.-J., Grey, Francois, Bohr, Jakob, Bernaerts, D., Van Tendeloo, G., Amelinckx, S., Hevesi, K., Gensterblum, G., Yu, L.M., Pireaux, J.-J., Grey, Francois, and Bohr, Jakob

Abstract

A transmission electron microscopy study of epitaxial C60 and C70 films grown on a GeS (001) surface is presented. The relationship between the orientation of the substrate and the films and structural defects in the films, such as grain boundaries, unknown in bulk C60 and C70 crystals, are studied. Small misalignments of the overlayers with respect to the orientation of the substrate, so-called epitaxial rotations, exist mainly in C70 films, but also sporadically in the C60 overlayers. A simple symmetry model, previously used to predict the rotation of hexagonal overlayers on hexagonal substrates, is numerically tested and applied to the present situation. Some qualitative conclusions concerning the substrate-film interaction are deduced. ©1996 American Institute of Physics.

Published
1996

15. Resonant interaction of low energy electrons with intramolecular vibrations in solid C60

Author

FUNDP - SPHY_LISE (laboratoire interdépartemental de spectroscopie électronique), Hevesi, K., Fustin, Charles-André, Rudolf, P., Yu, L.-M., Han, B.-Y., Gensterblum, G., Thiry, P.A., Pireaux, J.-J., Caudano, R., FUNDP - SPHY_LISE (laboratoire interdépartemental de spectroscopie électronique), Hevesi, K., Fustin, Charles-André, Rudolf, P., Yu, L.-M., Han, B.-Y., Gensterblum, G., Thiry, P.A., Pireaux, J.-J., and Caudano, R.

Abstract

The energy-dependant cross sections of the impact-excited intramolecular vibrations in an epitaxial C60(111) film have been measured by High Resolution Electron Energy Loss Spectroscopy (HREELS). A Negative Ion Resonance (NIR) behaviour is evidenced by a dramatic cross-section enhancement at a primary energy of ∼2.9 eV together with some fine structures on the high energy side. Through comparison with experimental results on the unoccupied states and on the electronic excitations of solid C60, these NIR structures can be correlated to a temporary trapping of the probing electron in the LUMO+3-derived state in the framework of an 'electronic excitation associated' NIR process. © 1995.

Published
1995

18. Vibrational study of C60 overlayers on

Author

Dumas, P., primary, Gruyters, M., additional, Rudolf, P., additional, He, Y., additional, Yu, L.-M., additional, Gensterblum, G., additional, Caudano, R., additional, and Chabal, Y.J., additional

Published
1996
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31. Growth mode and electronic structure of the epitaxialC60(111)/GeS(001) interface

Author

Gensterblum, G., primary, Hevesi, K., additional, Han, B.-Y., additional, Yu, L.-M., additional, Pireaux, J.-J., additional, Thiry, P. A., additional, Caudano, R., additional, Lucas, A.-A., additional, Bernaerts, D., additional, Amelinckx, S., additional, Van Tendeloo, G., additional, Bendele, G., additional, Buslaps, T., additional, Johnson, R. L., additional, Foss, M., additional, Feidenhans’l, R., additional, and Le Lay, G., additional

Published
1994
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33. Experimental evidence for 400-meV valence-band dispersion in solidC60

Author

Gensterblum, G., primary, Pireaux, J.-J., additional, Thiry, P. A., additional, Caudano, R., additional, Buslaps, T., additional, Johnson, R. L., additional, Le Lay, G., additional, Aristov, V., additional, Günther, R., additional, Taleb-Ibrahimi, A., additional, Indlekofer, G., additional, and Petroff, Y., additional

Published
1993
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38. RESONANCE EFFECTS OBSERVED IN THE INTERACTION OF LOW-ENERGY ELECTRONS AND INTRAMOLECULAR VIBRATIONS OF SOLID 70.

Author

YU, L.-M., HAN, B.-Y., HEVESI, K., RUDOLF, P., GENSTERBLUM, G., THIRY, P.A., PIREAUX, J.-J., CAUDANO, R., and LAMBIN, PH.

Abstract

The intramolecular vibrations of a thick epitaxial 70(111) film on (001) have been measured by high-resolution electron energy-loss spectroscopy (HREELS). A negative-ion resonant behavior is observed in the energy dependence of the impact scattering differential cross sections. These resonances are described as electronic excitation associated shape resonances, which are coincident with the electron energy loss and free-electron capture experiments. Finally, the effect of charge transfer on the resonance behavior is discussed through the comparison of bulk spectra with those from an adsorbed monolayer of 70 on (110). [ABSTRACT FROM AUTHOR]

Published
1995
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39. Scanning and friction-force microscopy of thin C60 films on GeS(001)

Author

Allers, W., Schwarz, U. D., Gensterblum, G., and Wiesendanger, R.

Abstract

The surface morphology of thin C60 films grown epitaxially under ultra-high vacuum conditions on layered GeS(001) substrates has been studied by scanning force microscopy. The individual C60 layers were imaged down to molecular resolution. The growth mechanism was found to be of layer-by-layer type at the initial stages of growth, but seems to be very sensitive to the substrate temperature. The tribological properties of these films have been probed simultaneously by means of lateral force microscopy. The frictional coefficient of the C60 layers was determined to be significantly smaller than the frictional coefficient of the GeS substrate. This demonstrates that well-ordered C60 films can have even better lubricating properties than a layered material.

Published
1994
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40. C60 growth on Si(100), GaSe(0001) and GeS(001)

Author

Gensterblum, G., Yu, L. -M., Pireaux, J. -J., Thiry, P. A., Caudano, R., Themlin, J. -M., Bouzidi, S., Coletti, F., and Debever, J. -M.

Abstract

C60 films have been grown in ultra high vacuum on various crystalline substrates and the structure of the films has been investigated by low energy electron diffraction (LEED) and high resolution electron energy loss spectroscopy (HREELS). The C60 films form randomly oriented nanocrystals on Si(100), mesoscopic polycrystals on GaSe(0001) and microscopic single crystals on GeS(001). The vibrational structure of the C60/substrate interfaces is analyzed in detail by HREELS carried out in the dipole and impact scattering regimes. It is shown that the epitaxy of C60 on GeS(001) is induced by the weak van der Waals bonding and the peculiar corrugation of the substrate surface.

Published
1993
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41. C growth on Si(100), GaSe(0001) and GeS(001).

Author

Gensterblum, G., Yu, L., Pireaux, J., Thiry, P., Caudano, R., Themlin, J., Bouzidi, S., Coletti, F., and Debever, J.

Abstract

C films have been grown in ultra high vacuum on various crystalline substrates and the structure of the films has been investigated by low energy electron diffraction (LEED) and high resolution electron energy loss spectroscopy (HREELS). The C films form randomly oriented nanocrystals on Si(100), mesoscopic polycrystals on GaSe(0001) and microscopic single crystals on GeS(001). The vibrational structure of the C/substrate interfaces is analyzed in detail by HREELS carried out in the dipole and impact scattering regimes. It is shown that the epitaxy of C on GeS(001) is induced by the weak van der Waals bonding and the peculiar corrugation of the substrate surface. [ABSTRACT FROM AUTHOR]

Published
1993
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