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Laboratoire d’analyse et d’architecture des systèmes

Publications de l'équipe M3

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23documents trouvés

18147
03/05/2018

Insight into the Bonding of Silanols to Oxidized Aluminum Surfaces

M.POBERZNIK, D.COSTA, A.HEMERYCK, A.KOKALJ

Ljubljana, IRCP, M3, Institut Jožef Stefan

Revue Scientifique : Journal of Physical Chemistry C, Vol.122, N°17, pp.9417-9431, Mai 2018 , N° 18147

Lien : https://hal.laas.fr/hal-01810862

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Abstract

In the context of elucidating the mechanism by which siloxane-based sol–gel coatings adhere to the surface, the adsorption of a model silanol molecule, CH3Si(OH)3, and its oligomers (up to the trimer) on oxidized and fully hydroxylated aluminum substrates is described using density functional theory (DFT). To link our calculations with the synthesis of siloxane-based sol–gel coatings, the focus is given on the condensation mechanism. We find that the formation of a monodentate bonding mode with the hydroxylated surface via the condensation mechanism is exothermic by ≥0.5 eV in all considered cases. In contrast, the formation of a bidentate bonding mode is exothermic only for the trimer. However, taking entropic contributions into account, we find that the formation of the bidentate bonding mode is exergonic already for the dimer due to favorable entropic effects of a liberated water molecule during the reaction. In contrast, the reaction entropy is unfavorable for the monodentate formation because the effects of the immobilized silanol molecule counteract and surpass those of the liberated water molecule. The monodentate to bidentate transformation is therefore determined by the interplay between entropy and energy, and we find that the longer the oligomer chain, the more likely is the bidentate formation due to increasingly favorable reaction energies. These results further reveal that for the silanol monomer, additional molecule–surface chemical bonds do not form via the condensation mechanism due to the strained configuration it has to adopt in the bidentate bonding mode.

143814
18096
01/03/2018

Spatial Analysis of Nanofluidic-Embedded Biosensors for Wash-Free Single-Nucleotide Difference Discrimination

J.CACHEUX, M.BRUT, A.BANCAUD, P.CORDELIER, T.LEICHLE

MEMS, M3, MILE, CRCT-INSERM

Revue Scientifique : ACS Sensors, Vol.3, N°3, pp.606-611, Mars 2018 , N° 18096

Lien : https://hal.laas.fr/hal-01762631

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In this work, we demonstrate that the analysis of spatially resolved nanofluidic-embedded biosensors permits the fast and direct discrimination of single-nucleotide difference (SND) within oligonucleotide sequences in a single step interaction. We design a sensor with a linear dimension much larger than the channel depth in order to ensure that the reaction over the whole sensor is limited by the convection rate. Thus, the targets are fully collected, inducing a nonuniform spatial hybridization profile. We also use the nanoscale height of the channel, which enables us to minimize the amount of labeled molecules flowing over the sensor and hence to reduce the fluorescence background, to carry out real-time hybridization detection by fluorescence microscopy. Taken together, these design rules allow us to show that the spatial hybridization profile depends on the duplex affinity, and we speculate that the on and off-rate constants can be inferred during target injection, which is not possible in local analysis where the dissociation step through rinsing must be conducted. We finally manage to discriminate a GT mismatch on a microRNA sequence by optimizing the interaction temperature and the probe design after a few minutes of interaction in a single step protocol. This work may be applied to any biosensing transduction scheme with spatial resolution, e.g., surface plasmon resonance imaging, integrated into nanofluidic channels for applications where high oligonucleotide sequence selectivity and short analysis times are required.

143275
18017
08/02/2018

Simulation of Single Particle Displacement Damage in Silicon – Part III: First Principles Characterization of Defect Properties

A.JAY, A.HEMERYCK, N.RICHARD, L.MARTIN SAMOS, M.RAINE, A.LE ROCH, N.MOUSSEAU, V.GOIFFON, P.PAILLET, P.PAILLET, M.GAILLARDIN, P.MAGNAN

ISAE, M3, CEA-DAM, UNG, UdeM

Revue Scientifique : IEEE Transactions on Nuclear Science, 8p., Février 2018, DOI 10.1109/TNS.2018.2790843 , N° 18017

Lien : https://hal.archives-ouvertes.fr/hal-01685608

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Abstract

A first principles study of the defects generated by displacement cascades in silicon is performed. This work is particularly focused on two defect configurations; the di-vacancy and the tri-interstitial, both identified in previous Molecular Dynamics (MD) and kinetic Activation Relaxation Technique (k-ART) simulations [1, 2]. By combining structural, energy and migration properties evaluated within the framework of the standard Density Functional Theory (DFT) and electronic properties calculated within the G 0 W 0 approximation, a reconstruction of the corresponding thermally-activated electrical signal generated by each defect is obtained. Their contribution to Dark Current (DC) and Dark Current Random Telegraph Signal (DC-RTS) measured in image sensors is then discussed.

142335
17312
01/01/2018

Growth, stability and decomposition of Mg 2 Si ultra-thin films on Si (100)

B.SARPI, R.ZIRMI, M.PUTERO, M.BOUSLAMA, A.HEMERYCK, S.VIZZINI

IM2NP, LATAGE, LSM, M3

Revue Scientifique : Applied Surface Science, Vol.423, N°Part B, pp.522-527, Janvier 2018 , N° 17312

Lien : https://hal.laas.fr/hal-01583845

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Abstract

Using Auger Electron Spectroscopy (AES), Scanning Tunneling Microscopy/Spectroscopy (STM/STS) and Low Energy Electron Diffraction (LEED), we report an in-situ study of amorphous magnesium silicide (Mg2Si) ultra-thin films grown by thermally enhanced solid-phase reaction of few Mg monolayers deposited at room temperature (RT) on a Si(100) surface. Silicidation of magnesium films can be achieved in the nanometric thickness range with high chemical purity and a high thermal stability after annealing at 150 °C, before reaching a regime of magnesium desorption for temperatures higher than 350 °C. The thermally enhanced reaction of one Mg monolayer (ML) results in the appearance of Mg2Si nanometric crystallites leaving the silicon surface partially uncovered. For thicker Mg deposition nevertheless, continuous 2D silicide films are formed with a volcano shape surface topography characteristic up to 4 Mg MLs. Due to high reactivity between magnesium and oxygen species, the thermal oxidation process in which a thin Mg2Si film is fully decomposed (0.75 eV band gap) into a magnesium oxide layer (6–8 eV band gap) is also reported.

140918
17234
01/12/2017

DFT-D study of adsorption of diaminoethane and propylamine molecules on anatase (101) TiO 2 surface

A.HEMERYCK, A.MOTTA, C.LACAZE-DUFAURE, D.COSTA, P.MARCUS

M3, IRCP, CIRIMAT

Revue Scientifique : Applied Surface Science, Vol.426, pp.107-115, Décembre 2017 , N° 17234

Lien : https://hal.laas.fr/hal-01574752

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Abstract

The adsorption on anatase (101) TiO 2 surface of two model amines, diaminoethane (DAE) and propylamine (PPA), was investigated using Density Functional Theory-Dispersion included (DFT-D) calculations. The investigated coverage is ranging from 0.25 monolayer to full coverage (one amine molecule per surface Ti ion). Both interactions of the adsorbed layer with the anatase (101) TiO 2 surface and inter-molecular interactions are described. A structural transition from a bridge to a perpendicular structure is found for DAE when evolving from 0.25 monolayer to full coverage. At full coverage, a dense, ordered adhesive layer is formed. For DAE, at intermediate coverage, different isoenergetic configurations are found and structural transition from a bridge to a perpendicular structure is found. In contrast, the adsorption mode of PPA is more regular with only perpendicularly adsorbed molecules at all investigated coverages. Dispersion forces already account for 40% of the adsorption energy at low coverage (0.25 ML) and are the driving force for monolayer formation with a contribution of 60% up to 100% at high coverage. As revealed by molecular dynamics, the molecules can change their orientation towards the surface in a concerted way.

140521
17496
01/11/2017

MgO monolayer epitaxy on Ni (100)

B.SARPI, M.PUTERO, A.HEMERYCK, S.VIZZINI

IM2NP, M3

Revue Scientifique : Applied Physics Letters, Vol.111, N°21, 211604p., Novembre 2017 , N° 17496

Lien : https://hal.archives-ouvertes.fr/hal-01685588

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The growth of two-dimensional oxide films with accurate control of their structural and electronic properties is considered challenging for engineering nanotechnological applications. We address here the particular case of MgO ultrathin films grown on Ni (100), a system for which neither crystallization nor extended surface ordering have been established previously in the monolayer range. Using Scanning Tunneling Microscopy (STM) and Auger Electron Spectroscopy (AES), we report on experiments showing MgO monolayer (ML) epitaxy on a ferromagnetic nickel surface, down to the limit of atomic thickness. Alternate steps of Mg ML deposition, O2 gas exposure, and ultrahigh vacuum (UHV) thermal treatment enable the production of a textured film of ordered MgO nano-domains. This study could open interesting prospects for controlled epitaxy of ultrathin oxide films with high magneto-resistance (MR) ratio on ferromagnetic substrates, enabling improvement in high-efficiency spintronics and magnetic tunnel junction devices.

142196
17595
26/10/2017

Rapid discrimination of single-nucleotide differences through the spatial analysis of a nanofluidic-embedded biosensor

J.CACHEUX, M.BRUT, A.BANCAUD, P.CORDELIER, T.LEICHLE

MEMS, M3, MILE, CRCT-INSERM

Manifestation avec acte : International Conference on Miniaturized Systems for Chemistry and Life Sciences ( MicroTas ) 2017 du 22 octobre au 26 octobre 2017, Savannah (USA), Octobre 2017, 2p. , N° 17595

Lien : https://hal.laas.fr/hal-01699274

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Abstract

We demonstrate that the spatial analysis of nanofluidic-embedded biosensors permits the fast and direct discrimination of single-nucleotide difference (SND) within microRNA sequences in a single step interaction. We first show that the spatial hybridization profile depends on the duplex affinity, and we speculate that the affinity constant can be inferred during target injection, which is not possible in local analysis where the dissociation step through rinsing must be conducted. We finally manage to discriminate a GT mismatch on a microRNA sequence.

142847
17498
01/10/2017

Ambient Humidity Influence on CO Detection with SnO 2 Gas Sensing Materials. A Combined DRIFTS/DFT Investigation

S.WICKER, M.GUILTAT, U.WEIMAR, A.HEMERYCK, N.BARSAN

Tubingen, M3

Revue Scientifique : Journal of Physical Chemistry C, Vol.121, N°45, pp.25064-25073, Octobre 2017 , N° 17498

Lien : https://hal.archives-ouvertes.fr/hal-01685597

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Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) and first-principles calculations are performed to investigate the different ways in which water reacts with a SnO 2 surfaces and to evaluate the cross interference of humidity on the detection of CO. Two different materials, chosen because of their very different properties, were investigated. The experimental results were interpreted with the help of theoretical modelling of two clean and defective surfaces, namely (110) and (101). The experimental results show, and the theoretical calculations confirm, that water vapor can interfere with the CO detection in different ways depending on the active surface and the concentration of oxygen vacancies. This is related to the different ways in 2 which the water vapor reacts with tin oxide; on the one hand it can reduce the (101) surface, on the other hand it can heal the oxygen vacancies of the defective (110) surface.

142215
17235
01/09/2017

Modeling of the interface formation during CuO deposition on Al(111) substrate: linking material design and elaboration process parameters through multi-levels approach

M.GUILTAT, N.SALLES, M.BRUT, G.LANDA, N.RICHARD, S.VIZZINI, A.HEMERYCK

M3, CEA-DAM, IM2NP

Revue Scientifique : Modelling and Simulation in Materials Science and Engineering, Vol.25, N°6, 064005p., Septembre 2017 , N° 17235

Lien : https://hal.laas.fr/hal-01574744

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In this paper, we use a multi-levels modeling approach to describe the elaboration of directly integrated energetic materials. The deposition of copper oxide on aluminum substrate is described. Atomic scale calculations are first conducted to identify local mechanisms involved during the growth of CuO on Al(111). These atomic scale data are then used to parameterize a macroscopic code, inspired on a kinetic Monte Carlo methodology dedicated to simulate vapor like deposition process. The objective is to establish the link between the microstructure of materials and the way they are achieved, i.e. the process parameters such as temperature and gas pressure. This work is conducted in the context of the integration of nano-structured energetic thermites used as micro energy source in microelectronic devices. We show that the temperature of the deposition process appears as the driving parameter to tailor the thickness of interfacial layers.

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17233
01/08/2017

Strain-driven diffusion process during silicon oxidation investigated by coupling density functional theory and activation relaxation technique

N.SALLES, N.RICHARD, N.MOUSSEAU, A.HEMERYCK

M3, CEA-DAM, UdeM

Revue Scientifique : The Journal of Chemical Physics, Vol.147, N°5, 054701p., Août 2017 , N° 17233

Lien : https://hal.laas.fr/hal-01574755

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The reaction of oxygen molecules on an oxidized silicon model-substrate is investigated using an efficient potential energy hypersurface exploration that provides a rich picture of the associated energy landscape, energy barriers, and insertion mechanisms. Oxygen molecules are brought in, one by one, onto an oxidized silicon substrate, and accurate pathways for sublayer oxidation are identified through the coupling of density functional theory to the activation relaxation technique nouveau, an open-ended unbiased reaction pathway searching method, allowing full exploration of potential energy surface. We show that strain energy increases with O coverage, driving the kinetics of diffusion at the Si/SiO 2 interface in the interfacial layer and deeper into the bulk: at low coverage, interface reconstruction dominates while at high coverage, oxygen diffusion at the interface or even deeper into the bottom layers is favored. A changing trend in energetics is observed that favors atomic diffusions to occur at high coverage while they appear to be unlikely at low coverage. Upon increasing coverage, strain is accumulated at the interface, allowing the oxygen atom to diffuse as the strain becomes large enough. The observed atomic diffusion at the interface releases the accumulated strain, which is consistent with a layer-by-layer oxidation growth.

140519
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