Peer-reviewed Publications |
Aufray, B., Kara, A., Vizzini, S., Oughaddou, H., Leandri, C., Ealet, B., & Le Lay, G. (2010). Graphene-like silicon nanoribbons on Ag(110): A possible formation of silicene. APPLIED PHYSICS LETTERS, 96(18), 183102.
Résumé: Scanning tunneling microscopy (STM) and ab initio calculations based on density functional theory (DFT) were used to study the self-aligned silicon nanoribbons on Ag(110) with honeycomb, graphene-like structure. The silicon honeycombs structure on top of the silver substrate is clearly observed by STM, while the DFT calculations confirm that the Si atoms adopt spontaneously this new silicon structure. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3419932]
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De Padova, P., Quaresima, C., Ottaviani, C., Sheverdyaeva, P. M., Moras, P., Carbone, C., Topwal, D., Olivieri, B., Kara, A., Oughaddou, H., Aufray, B., & Le Lay, G. (2010). Evidence of graphene-like electronic signature in silicene nanoribbons. APPLIED PHYSICS LETTERS, 96(26), 261905.
Résumé: We report on the electronic properties of straight, 1.6 nm wide, silicene nanoribbons on Ag(110), arranged in a one-dimensional grating with a pitch of 2 nm, whose high-resolution scanning tunneling microscopy images reveal a honeycomb geometry. Angle-resolved photoemission shows quantum confined electronic states of one-dimensional character. The silicon band dispersion along the direction of the nanoribbons suggests a behavior analogous to the Dirac cones of graphene on different substrates. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3459143]
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El Asri, T., Raissi, M., Vizzini, S., El Maachi, A., Ameziane, E. L., d'Avitaya, F. A., Lazzari, J. L., Coudreau, C., Oughaddou, H., Aufray, B., & Kaddouri, A. (2010). Inter-diffusion of cobalt and silicon through an ultra thin aluminum oxide layer. APPLIED SURFACE SCIENCE, 256(9), 2731–2734.
Résumé: Optical emission spectroscopy of sputtered species during ion bombardment, Auger electron spectroscopy and high-resolution transmission electron microscopy were used to study the cobalt and silicon diffusion through the interfaces of Co/AlO/Si(0 0 1) hetero-structure. The results are discussed as a function of the annealing temperature of sample and show that the diffusion process at the interfaces starts for annealing temperatures above 200 degrees C without detectable modification of the oxide layer. (C) 2009 Elsevier B. V. All rights reserved.
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Kara, A., Vizzini, S., Leandri, C., Ealet, B., Oughaddou, H., Aufray, B., & Lelay, G. (2010). Silicon nano-ribbons on Ag(110): a computational investigation. JOURNAL OF PHYSICS-CONDENSED MATTER, 22(4), 045004.
Résumé: We report results of a computational investigation, based on density functional theory, of silicon self-assembled nano-ribbons (Si NRs) on Ag(110). These NRs present a honeycomb-like structure arched on the substrate and forming a closed-packed structure. The calculated STM images match the experimental ones, hinting to a possible new Si structure, mediated by the Ag substrate. The observed new electronic states near the Fermi level were reproduced by the calculations and attributed to a confinement/hybridization tandem.
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Lalmi, B., Oughaddou, H., Enriquez, H., Kara, A., Vizzini, S., Ealet, B., & Aufray, B. (2010). Epitaxial growth of a silicene sheet. APPLIED PHYSICS LETTERS, 97(22), 223109.
Résumé: Using atomic resolved scanning tunneling microscopy, we present here the experimental evidence of a silicene sheet (graphenelike structure) epitaxially grown on a close-packed silver surface [Ag(111)]. This has been achieved via direct condensation of a silicon atomic flux onto the single-crystal substrate in ultrahigh vacuum conditions. A highly ordered silicon structure, arranged within a honeycomb lattice, is synthesized and present two silicon sublattices occupying positions at different heights (0.02 nm) indicating possible sp(2)-sp(3) hybridizations. (C) 2010 American Institute of Physics. [doi:10.1063/1.3524215]
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Raissi, M., Vizzini, S., Langer, G., Rochdi, N., Oughaddou, H., Coudreau, C., Nitsche, S., D'Avitaya, F. A., Aufray, B., & Lazzari, J. L. (2010). Interfacial solid phase reactions in cobalt/aluminum oxide/silicon(001) system. THIN SOLID FILMS, 518(21), 5992–5994.
Résumé: Auger electron spectroscopy, secondary neutral mass spectrometry and high-resolution transmission electron microscopy were used to assess the chemical, morphological and structural modifications after annealing of cobalt/aluminum oxide/silicon(001) hetero-structure The results show that the aluminum oxide forms a diffusion barrier for temperatures lower than 200 degrees C. Beyond this temperature, cobalt atoms diffuse in the silicon region without apparent modification of the barrier At 340 degrees C, the asymmetric diffusion could be explained by the formation of an AlCoO complex oxide playing the role of a diffusion barrier for Si atoms. (C) 2010 Elsevier B V All rights reserved
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Raseev, G., & Bejan, D. (2010). Multipole surface plasmon resonance of an aluminium surface. Opt. Commun., 283(20), 3976–3984.
Résumé: The surface photoelectric effect and the surface plasmon resonances appear when a p/transverse magnetic polarized laser hits a gas-solid interface. We model this effect in the long wave length (LWL) domain (lambda(vac)>10 nm, (h) over cap omega<124 eV) by combining the Ampere-Maxwell equation, written in classical approximation, with the material equation for the susceptibility. The resulting model, called the vector potential from the electron density (VPED), calculates the susceptibility as a product of the bulk susceptibility and the electron density of the actual system. The bulk susceptibility is a sum of the bound electron scalar susceptibility taken from the experiment and of the conduction electron non-local isotropic susceptibility tensor in a jellium metal (Lindhard, 1954 [1]). The electron density is the square of the wave function solution of the Schrodinger equation. The analysis of observables, the reflectance R and the photoelectron yield Y as well as the induced charge density permits to identify and characterize the multipole surface plasmon resonance of Al(111) appearing at omega(m) similar to 0.8 omega(p), or 11-12 eV. (c) 2010 Elsevier B.V. All rights reserved.
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Riedel, D. (2010). Single molecule manipulation at low temperature and laser scanning tunnelling photo-induced processes analysis through time-resolved studies. JOURNAL OF PHYSICS-CONDENSED MATTER, 22(26), 264009.
Résumé: This paper describes, firstly, the statistical analysis used to determine the processes that occur during the manipulation of a single molecule through electronically induced excitations with a low temperature (5 K) scanning tunnelling microscope (STM). Various molecular operation examples are described and the ability to probe the ensuing molecular manipulation dynamics is discussed within the excitation context. It is, in particular, shown that such studies can reveal reversible manipulation for tuning dynamics through variation of the excitation energy. Secondly, the photo-induced process arising from the irradiation of the STM junction is also studied through feedback loop dynamics analysis, allowing us to distinguish between photo-thermally and photo-electronically induced signals.
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Riedel, D., Delattre, R., Borisov, A. G., & Teperik, T. V. (2010). A Scanning Tunneling Microscope as a Tunable Nanoantenna for Atomic Scale Control of Optical-Field Enhancement. Nano Lett., 10(10), 3857–3862.
Résumé: The high stability of a low temperature (9 K) scanning tunneling microscope junction is used to precisely adjust the enhancement of an external pulsed vacuum ultraviolet (VUV) laser The ensuing VUV optical-field strength is mapped on an hydrogenated Si(100) surface by imprinting locally one-photon atomic scale hydrogen desorption Subsequent to irradiation, topography of the Si(100) H surface at the reacted area revealed a desorption spot with unprecedented atomic precision Our results show that the shapes. positions. and sizes of the desorption spots are correlated to the calculated optical-field structure, offering real control of the optical-held distribution at molecular scale
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