Peer-reviewed Publications |
Anouchah Momeni, P. S., Patrick Rousseau, Hocine Khemliche, and Philippe Roncin. (2010). Grazing Incidence Fast Atom Diffraction (GIFAD): Doing RHEED with Atoms. e-J. Surf. Sci. Nanotech, 8, 101–104.
Résumé: We describe a new diffraction technique to investigate the surface of single crystal surfaces. Its geometry is the
same as that of the RHEED technique. In GIFAD, instead of 10-30 keV electrons, the projectiles are neutral atoms
(mainly helium) with energies in the keV range. We present few results obtained with GIFAD highlighting the
simplicity of interpretation.
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Bobrov, K., & Guillemot, L. (2010). Strain engineering tunable nanotemplates on the Cu(110)-(2 x 1)-O surface. SURFACE SCIENCE, 604(21-22), 1894–1898.
Résumé: We present an STM study on the domain pattern formation of the Cu(110)-O surface. We found that the separation of the oxygen adsorbate phase into the domain pattern is consistent with a phenomenological model of size-dependent elastic relaxation of the strained surface. We developed a thermally assisted oxygen adsorption procedure aiming to control the size of the two-dimensional (2x1)-O islands nucleated at the surface under oxygen adsorption serving as precursors for domain pattern formation. We engineered wide range tuneable (2x1)-O domain patterns by controlling the nuclei size and the oxygen coverage at the pattern formation stage. (C) 2010 Elsevier B.V. All rights reserved.
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Chen, L., Valdes, J. E., Vargas, P., & Esaulov, V. A. (2010). Surface channelling and energy losses of 4 keV hydrogen and fluorine ions in grazing scattering on Au(111) and missing row reconstructed Au(110) surfaces. Journal of physics, 22(34), 345005.
Résumé: We present the results of an experimental and theoretical study of surface channelling and energy loss of 4 keV hydrogen and fluorine ions in grazing scattering on a missing row reconstructed Au(110) surface and a Au(111) surface. We performed measurements of energy losses for grazing angle scattering in surface channelling conditions for various azimuthal orientations of the crystal. Experimental results are discussed in the light of trajectory calculations of hydrogen and fluorine ions scattered under grazing incidence conditions on the surface. A nonlinear model is used in order to calculate the ion energy loss in these crystalline systems. Ab initio electronic crystal structure calculations and semi-classical simulations are performed and allow us to delineate various trajectory classes that correspond to different contributions in the energy loss spectra for various azimuthal orientations of the surface.
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Hamoudi, H., Prato, M., Dablemont, C., Cavalleri, O., Canepa, M., & Esaulov, V. A. (2010). Self-Assembly of 1,4-Benzenedimethanethiol Self-Assembled Monolayers on Gold. LANGMUIR, 26(10), 7242–7247.
Résumé: A study of the self-assembly of 1,4-benzenedimethanethiol (BDMT; HS-CH(2)-(C(6)H(4))-CH(2)-SH) monolayers on gold is presented. Self-assembled monolayers (SAM) are characterized by reflection absorption infrared spectroscopy (RAIRS), X-ray photoelectron spectroscopy (XPS), and spectroscopic ellipsometry (SF) measurements. The ensemble of measurements consistently shows that well-organized BDMT SAMs, with “standing-up” molecules, can be obtained on high quality gold films with incubation in n-hexane provided that N(2)-degassed solutions are used and all preparation steps are performed at 60 degrees C in the absence of ambient light. SE data indicate that the optical interface properties of the BDMT-Au system are different from those of simple alkanethiol SAMs. A possible mechanism for the formation of the “standing-up” phase from the lying-down phase via a hydrogen exchange reaction involving chemisorbed lying-clown and free dithiol molecules is discussed.
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Salazar Alarcon, L., Chen, L., Esaulov, V. A., Gayone, J. E., Sanchez, E. A., & Grizzi, O. (2010). Thiol Terminated 1,4-Benzenedimethanethiol Self-Assembled Monolayers on Au(111) and InP(110) from Vapor Phase. JOURNAL OF PHYSICAL CHEMISTRY C, 114(47), 19993–19999.
Résumé: We present results of a clean vacuum evaporative adsorption method of assembly of the conjugated dithiol molecule 1,4-benzenedimethanethiol on the surfaces of gold and indium phosphide. Measurements of direct recoil spectroscopy with time-of-flight analysis show in both cases formation of a self-assembled monolayer (SAM) with S atoms available at the SAM-vacuum interface. Investigation of the adsorption kinetics shows that a lying-down phase is formed at low exposures, which precedes the standing up SAM phase. The standing up SAM formation requires exposures of the order of a mega Langmuir. A study of the SAM stability with temperature shows that the S terminated layer survives up to similar to 370 K, above this temperature a reordering of the layer takes piece where S atoms are no longer available at the vacuum interface. Final desorption occurs around 450 K for Au and around 500K for InP.
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