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36 results on '"Bourquard, Florent"'

7. Ultrafast Laser‐Induced Sub‐100 nm Structures on Tungsten Surfaces: Stretched Liquid Dynamics Insights.

Author

Dominic, Priya, Iabbaden, Djafar, Bourquard, Florent, Reynaud, Stéphanie, Weck, Arnaud, Colombier, Jean-Philippe, and Garrelie, Florence

Subjects
FEMTOSECOND lasers, SURFACE structure, THERMAL stresses, LIQUID surfaces, CAVITATION
Abstract

The origin of high‐spatial‐frequency laser‐induced periodic surface structures, known as HSFLs, has always been a controversial topic. HSFLs of sub‐100 nm periodicity and sub‐20 nm amplitude are generated on tungsten by Ti:sapphire femtosecond laser irradiation under four different processing environments (ambient, air at 10 mbar, Ar at 10 mbar, and vacuum at 10−7 mbar). The topography and subtopography analysis together with two‐temperature model–molecular dynamics simulations reveal that HSFLs formation originates from laser‐induced thermal stresses, implying both surface tension and tensile forces are involved. The experimental observation of subsurface cavitation confirms a hydrodynamics‐based origin for these nanostructures. [ABSTRACT FROM AUTHOR]

Published
2024
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16. SiN/VO2/SiN Sandwich‐Based Resonant Waveguide Grating to Produce Thermally Activated Optical Components.

Author

Bleu, Yannick, Bruhier, Hugo, Pouit, Thomas, Valour, Arnaud, Jamon, Damien, Crespo‐Monteiro, Nicolas, Dubost, Laurent, Bourquard, Florent, Donnet, Christophe, Parriaux, Olivier, and Jourlin, Yves

Subjects
OPTICAL switches, OPTICAL switching, OPTICAL resonators, TRANSITION temperature, SANDWICH construction (Materials), OPTICAL gratings, METAL-insulator transitions, DELAYED fluorescence
Abstract

The insulator‐to‐metal transition (IMT) of vanadium dioxide (VO2) at ≈68 °C enables a variety of optical applications, including switching and modulation, and tuning of optical resonators. This work designs and demonstrates a novel thermally activated optical switch consisting of a SiN/VO2/SiN multilayer sandwich structure with an AMONIL‐based grating with a reduced transition temperature of 47 °C. The optical switching in the multilayer is due to the IMT of the VO2‐embedded layer. Here, the asymmetrical TE1 mode exhibiting a quasi‐zero electric field in the center of the multilayer waveguide is excited in the resonant waveguide grating (RWG) structure under normal incidence via the AMONIL‐based grating printed on top, leading to high resonant transmittance (75%) at room temperature. Increasing the temperature to more than 47 °C causes VO2 to undergo an insulator‐to‐metal transition accompanied by optical modifications in the IR region, completely canceling the resonance effect, while reducing the transmittance to 30%. Further, the modeling results aimed at optimizing the design of the experimental structure. These results demonstrate good performance of the proposed design and pave the way to fabricate VO2‐based optical switches for photonics applications including lasers, sensors, and detectors, in which external stimuli such as heat affect the transmittance or reflectance spectrum. [ABSTRACT FROM AUTHOR]

Published
2023
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19. Towards Room Temperature Phase Transition of W-Doped VO 2 Thin Films Deposited by Pulsed Laser Deposition: Thermochromic, Surface, and Structural Analysis.

Author

Bleu, Yannick, Bourquard, Florent, Barnier, Vincent, Loir, Anne-Sophie, Garrelie, Florence, and Donnet, Christophe

Subjects
*PHASE transitions, *PULSED laser deposition, *ELECTROCHROMIC effect, *THIN films, *THERMOCHROMISM, *TRANSITION temperature, *RAPID thermal processing, *SURFACE chemistry
Abstract

Vanadium dioxide (VO2) with an insulator-to-metal (IMT) transition (∼68 °C) is considered a very attractive thermochromic material for smart window applications. Indeed, tailoring and understanding the thermochromic and surface properties at lower temperatures can enable room-temperature applications. The effect of W doping on the thermochromic, surface, and nanostructure properties of VO2 thin film was investigated in the present proof. W-doped VO2 thin films with different W contents were deposited by pulsed laser deposition (PLD) using V/W (+O2) and V2O5/W multilayers. Rapid thermal annealing at 400–450 °C under oxygen flow was performed to crystallize the as-deposited films. The thermochromic, surface chemistry, structural, and morphological properties of the thin films obtained were investigated. The results showed that the V5+ was more surface sensitive and W distribution was homogeneous in all samples. Moreover, the V2O5 acted as a W diffusion barrier during the annealing stage, whereas the V+O2 environment favored W surface diffusion. The phase transition temperature gradually decreased with increasing W content with a high efficiency of −26 °C per at. % W. For the highest doping concentration of 1.7 at. %, VO2 showed room-temperature transition (26 °C) with high luminous transmittance (62%), indicating great potential for optical applications. [ABSTRACT FROM AUTHOR]

Published
2023
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23. Revisiting thin film of glassy carbon

Author

Diaf, Hatem, primary, Pereira, Antonio, additional, Melinon, Patrice, additional, Blanchard, Nicholas, additional, Bourquard, Florent, additional, Garrelie, Florence, additional, Donnet, Christophe, additional, and Vondráčk, Martin, additional

Published
2020
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24. Electroanalytical Performance of Nitrogen-Doped Graphene Films Processed in One Step by Pulsed Laser Deposition Directly Coupled with Thermal Annealing

Author

Consejo Superior de Investigaciones Científicas (España), Université de Lyon, Agence Nationale de la Recherche (France), Bourquard, Florent, Bleu, Yannick, Loir, Anne-Sophie, Caja-Munoz, Borja, Ávila, José, Asensio, María C., Raimondi, Gaëtan, Shokouhi, Maryam, Rassas, Ilhem, Farre, Carole, Chaix, Carole, Barnier, Vincent, Jaffrezic-Renault, Nicole, Garrelie, Florence, Donnet, Christophe, Consejo Superior de Investigaciones Científicas (España), Université de Lyon, Agence Nationale de la Recherche (France), Bourquard, Florent, Bleu, Yannick, Loir, Anne-Sophie, Caja-Munoz, Borja, Ávila, José, Asensio, María C., Raimondi, Gaëtan, Shokouhi, Maryam, Rassas, Ilhem, Farre, Carole, Chaix, Carole, Barnier, Vincent, Jaffrezic-Renault, Nicole, Garrelie, Florence, and Donnet, Christophe

Abstract

Graphene-based materials are widely studied to enable significant improvements in electroanalytical devices requiring new generations of robust, sensitive and low-cost electrodes. In this paper, we present a direct one-step route to synthetize a functional nitrogen-doped graphene film onto a Ni-covered silicon electrode substrate heated at high temperature, by pulsed laser deposition of carbon in the presence of a surrounding nitrogen atmosphere, with no post-deposition transfer of the film. With the ferrocene methanol system, the functionalized electrode exhibits excellent reversibility, close to the theoretical value of 59 mV, and very high sensitivity to hydrogen peroxide oxidation. Our electroanalytical results were correlated with the composition and nanoarchitecture of the N-doped graphene film containing 1.75 at % of nitrogen and identified as a few-layer defected and textured graphene film containing a balanced mixture of graphitic-N and pyrrolic-N chemical functions. The absence of nitrogen dopant in the graphene film considerably degraded some electroanalytical performances. Heat treatment extended beyond the high temperature graphene synthesis did not significantly improve any of the performances. This work contributes to a better understanding of the electrochemical mechanisms of doped graphene-based electrodes obtained by a direct and controlled synthesis process.

Published
2019

25. Electrochemical properties of nitrogen-doped graphene for environmental sensors

Author

Bourquard, Florent, Bleu, Yannick, Barnier, Vincent, Loir, Anne-Sophie, Chaix, Carole, Raimondi, Gaëtan, Lagarde, Florence, Jaffrezic-Renault, Nicole, Garrelie, Florence, Donnet, Christophe, Laboratoire Hubert Curien [Saint Etienne] (LHC), Université Jean Monnet [Saint-Étienne] (UJM)-Centre National de la Recherche Scientifique (CNRS)-Institut d'Optique Graduate School (IOGS), Laboratoire Georges Friedel (LGF-ENSMSE), École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Interfaces & biosensors - Interfaces & biocapteurs, Institut des Sciences Analytiques (ISA), Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), and PEPS Université de Lyon - CNRS

Subjects
[PHYS]Physics [physics], [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat]
Abstract

International audience; A promising way to tailor the chemical and electronic properties of graphene layers is the doping of the carbon honeycomb using heteroatoms such as nitrogen or boron. In the domain of electrochemical sensor, this may allow to control both conductivity and chemical activity. Nitrogen doped graphene was produced by the thermal annealing of nitrogen doped amorphous carbon (a-C:N) deposited either on a nickel thin film on a silicon substrate or between the silicon substrate and the nickel catalyst layer. The a-C:N thin films were produced by femtosecond pulsed laser ablation of graphite in nitrogen, while the nickel thin film was thermally evaporated. The nitrogen content and bonding configuration in the produced films were evaluated by XPS spectroscopy, with a particular attention to the ratio of pyridinic and pyrrolic bondings, the former being more interesting to control the conductivity and chemical activity of the film. The structure of the graphene was studied through microRaman spectroscopy using Raman mapping. Those results were compared to the electrochemical properties of the produced N-doped graphene films, studied through cyclic voltammetry using ferrocene as a redox probe. Electron transfer properties are compared to non-doped graphene films, which have already shown promising electrografting perspectives for advanced compound detection (1).(1) P. Fortgang et al., ACS Applied Materials and Interfaces 8 (2016) 1424-1433

Published
2018

27. Electroanalytical Performance of Nitrogen-Doped Graphene Films Processed in One Step by Pulsed Laser Deposition Directly Coupled with Thermal Annealing

Author

Bourquard, Florent, primary, Bleu, Yannick, additional, Loir, Anne-Sophie, additional, Caja-Munoz, Borja, additional, Avila, José, additional, Asensio, Maria-Carmen, additional, Raimondi, Gaëtan, additional, Shokouhi, Maryam, additional, Rassas, Ilhem, additional, Farre, Carole, additional, Chaix, Carole, additional, Barnier, Vincent, additional, Jaffrezic-Renault, Nicole, additional, Garrelie, Florence, additional, and Donnet, Christophe, additional

Published
2019
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30. DC nitrogen plasma assisted Femtosecond Pulsed Laser Deposition of Carbon-Nitrogen alloy for environmental analytical Microsystems: thin films characterization and in situ plume analysis

Author

Maddi, Chiranjeevi, Bourquard, Florent, Tite, Teddy, Zehani, Nedjla, Fortgang, Philippe, Loir, A.-S., Barnier, Vincent, Namour, Philippe, Lagarde, Florence, Rojas, Teresa-Cristina, Sanchez-Lopez, Juan Carlos, Chaix, Carole, Jaffrezic-Renault, Nicole, Wolski, Krzysztof, Donnet, Christophe, Garrelie, Florence, Laboratoire Hubert Curien [Saint Etienne] (LHC), Université Jean Monnet [Saint-Étienne] (UJM)-Centre National de la Recherche Scientifique (CNRS)-Institut d'Optique Graduate School (IOGS), Interfaces & biosensors - Interfaces & biocapteurs, Institut des Sciences Analytiques (ISA), Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Département Mécanique physique et interfaces (MPI-ENSMSE), École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-SMS, River Monitoring & Management - Suivi et gestion des rivières (2014-2016), Instituto de Ciencia de Materiales de Sevilla (ICMSE), and Universidad de Sevilla-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)

Subjects
[PHYS]Physics [physics], [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2015

35. Temporal pulse shaping effects on aluminium and boron ablation plumes generated by ultrashort pulsed laser ablation and analyzed by time- and space-resolved optical spectroscopy

Author

Bourquard, Florent, Colombier, Jean Philippe, Guillermin, Mathieu, Loir, Anne Sophie, Donnet, Christophe, Stoian, Razvan, Garrelie, Florence, Bourquard, Florent, Colombier, Jean Philippe, Guillermin, Mathieu, Loir, Anne Sophie, Donnet, Christophe, Stoian, Razvan, and Garrelie, Florence

Abstract

This paper focuses on the effect of temporal shaping of femtosecond laser pulses on laser ablation of aluminium and boron. The influence on plasma composition is deduced from optical emission investigations. Irradiation generated by the temporal tailoring of an incident laser pulse into double pulses or longer pulses is examined and compared to results deduced from hydrodynamic simulations of plasma temperature profiles. Above the ion formation threshold, increasing the delay in the double pulses sequence or increasing the pulse duration leads to an increase of the ion emission of the plasma plume of aluminium or boron. The observed increase with a saturation of ion emission at long delays or long pulse durations result from an interaction between the shaped laser pulse and the expanding matter after the onset of the plasma. Irradiation of boron with long pulses or double pulses reduces the production of nanoparticles, compared to the case of short pulses. Temporal shaping does not significantly affect the nanoparticle temperature, in spite of significant variations in the quantity of the ejected nanoparticles.

Published
2012

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