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International audience

International audience

International audience

International audience

International audience; The goal of this poster presentation is to give an overview of nanofabrication techniques commonly used for realization of nanostructures in our micro and nanofabrication facilities. We focus on all types of process equipment available in PLANETE, the CINaM clean room, which is a part of a regional technological platform CT PACA.First, we have applied a technique of microbead assisted lithography for fabrication of large area protein nanocluster arrays [1]. These biofunctionalized arrays were used for manipulating and imaging of living cells in order to study their adhesion and migration on nanostructured surfaces [2]. This method of surface patterning can also be applied for more complex studies of cell-cell interactions, where not only protein films but also lipid bilayer dot arrays need to be nanostructured [1]. Second, we have developed technological steps needed for microfabrication of field-effect-transistors using lipid layers as grid dielectrics [3,4]. The sensors based of these transistors exploit unprecedented mechanical and dielectric properties of ultrathin supported lipid monolayers [4].Chemical engineering of lipids allowed us to fabricate selective sensors for biologically important metal ions in solutions in large concentration range [3].Finally, we will show the fabrication steps necessary for fabrication of high aspect ratio molds of microfluidics. Such types of microcirculation devices have been used for comparative studies of the dynamics of healthy and non-healthy red blood cells by mimicking spleen slits [5].[1] E. Benard, F. Pi, I. Ozerov, A. Charrier, K. Sengupta, “Ligand Nano-cluster Array in Supported Lipid Bilayer”, J. Vis. Exp. 122, e55060 (2017)[2] F. Pi, P. Dillard, R. Alameddine, E. Benard, A. Wahl, I. Ozerov, A. Charrier, L. Limozin, K. Sengupta, “Size-Tunable Organic Nanodot Arrays: a Versatile Platform for Manipulating and Imaging Cells”, Nano Letters 15, 5178-5184 (2015)[3] T.D. Nguyen, A. Labed, R. El Zein, S. Lavandier, F. Bedu, I. Ozerov, H. Dallaporta, J.-M. Raimundo, A. M. Charrier, “A field effect transistor biosensor with a γ-pyrone derivative engineered lipid-sensing layer for ultrasensitive Fe3+ ion detection with low pH interference”, Biosensors and Bioelectronics 54, 571-577 (2014)[4] A. Kenaan, R. El Zein, V. Kilinc, S. Lamant, J.-M. Raimundo, A. M. Charrier, “Ultrathin Supported Lipid Monolayer with Unprecedented Mechanical and Dielectric Properties”, Adv. Func. Mat. 10.1002/adfm.201801024 (2018)[5] P. Gambhire, S. Atwell, C. Iss, F. Bedu, I. Ozerov, C. Badens, E. Helfer, A. Viallat and A. Charrier, “High aspect ratio sub-micron channels using wet etching: Application to the dynamics of red blood cell transiting through biomimetic splenic slits”, Small 13, 1700967 (2017)

International audience

International audience

International audience; Using angle-resolved inverse photoemission spectroscopy (KRIPES), we have investigated the unoccupied electronic structure of the model interface Sn/Si(1 1 1)-a-  3 p at room temperature. In addition to a ``metallic'' surface state crossing the Fermi level (E F) near the K H point, we unambiguously assign a second feature of our KRIPES spectra, located around 1.5 eV above E F , to a second surface state U H 2. We will experimentally show that U H 2 is an intrinsic feature of the a-  3 p reconstruction which cannot be associated with defects. The existence of these two surface states is not compatible with the ideal T 4 model which would show either a single, half-occupied metallic band crossing E F , or an insulating phase if strong correlation effects, important for these narrow surface bands, are considered. Rather, both U H 1 and U H 2 receive a natural explanation, once many-body effects are introduced, in the framework of a dynamical ¯uctuations model, where two kinds of Sn adatoms sites reminiscent of a low-temperature 3  3 phase do persist at room temperature. Correlated surface bands incorporating many-body effects in a non restricted way provide a complete description of the experimental surface bands and their dispersions. #

International audience; Due to the higher vapour pressure of silicon, silicon carbide surfaces annealed at high temperature under vacuum tend to graphitize. The comparison of graphite formation on the silicon and carbon terminations of 6H-SiC reveals significant differences in the graphitization mechanisms involved. The conduction-band structure of these interfaces has been Ž. determined by angle-resolved inverse photoemission spectroscopy KRIPES. Although the graphite layers grown on the C face are essentially polycrystalline, a small fraction of the film keeps a preferred orientation, where the graphite lattice basis vectors are rotated by 308 with respect to the basis vectors of the SiC lattice as in the case of the Si face. This in-plane disorder is in contrast with the growth of graphite on the Si face that takes place on a ''passivated'' adatom-terminated surface, leading to single-crystalline, heteroepitaxial graphite growth. The observation of unshifted p) states indicates a very small interaction of the first graphite monolayer with the Si face. In contrast, KRIPES reveals that the first graphite layer is strongly bound to the C face. A rehybridization of the graphite p) states with occupied orbitals of the substrate is inferred from an observed increase in the density of states in the vicinity of the Fermi level. q

International audience; This work presents a detailed comparison of the electronic properties of two phases a and g. of the prototypicalSi111.–'3 ='3 –Sn system, focussing on the empty surface states. The latter reconstruction has been studied at roomtemperature with inverse photoemission KRIPES.. For the g-phase characterised by an equal amount of Sn and Si adatoms,a charge transfer towards the Sn adatom leaves an empty surface state localised on Si adatoms, and observed in KRIPES 0.4eV above the Fermi level EF. at the surface Brillouin zone SBZ. center. The band gap of this semiconducting g-phase isestimated around 0.5 eV. In contrast, the a phase with only Sn adatoms shows a metallic behaviour and two distinctadatom-derived empty surface states.

The 13th International Conference on Miniaturized Systems for Chemistry and Life Sciences, Jeju, South Korea, November 01-05, 2009

European Molecular Biology Association Symposium: Biological Surfaces and Interfaces, Sant Feliu de Guixols, Spain, June 27-July 02, 2009