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International audience; Graphene is a remarkable two-dimensional (2D) material that is of great interest to both academia and industry. Several methods are used to produce either pristine graphene or doped graphene. Among these methods, Pulse Laser Deposition (PLD) has proved to be an alternative route for producing graphene layers from amorphous carbon thin films, due to many advantages including the controlled film thickness and dopant compositions in the films [1]. The present talk will review the ability of PLD to produce graphene and doped graphene films, mainly with nitrogen or boron atoms [2]. The growth mechanism will be highlighted on the basis of XPS investigations in situ during graphene growth. The film characteristics depending on the synthesis process are discussed mainly on the basis of Raman and XPS/AES investigations. Exploration of some electrical conduction properties are emphasized. In particular, electroanalytical experiments show that functionalized electrodes with nitrogen-doped graphene from PLD exhibits excellent reversibility, close to the theoretical value of 59 mV, and very high sensitivity to hydrogen peroxide oxidation [3]. The electroanalytical results were correlated with the composition and nanoarchitecture of the N-doped graphene film identified as a few-layer defected and textured graphene film containing a balanced mixture of graphitic-N and pyrrolic-N chemical functions. The present talk will help researchers to have an overview of the interest of PLD for graphene and doped-graphene synthesis.

International audience; In recent years, the research on graphene has received a lot of interest to both academia and industry due to its outstanding physical and chemical properties, and its potential for various applications. Due to this, several methods are used to produce either pristine graphene or doped graphene. Among these methods, Pulsed Laser Deposition (PLD) has proved to be an alternative route for producing graphene layers from amorphous carbon thin films, due to many advantages including the controlled film thickness and dopant compositions in the films [1]. The present talk will give an overview of the ability of PLD to fabricate graphene and doped graphene films, mainly with nitrogen or boron atoms [2]. The growth mechanism will be highlighted based on XPS investigations in situ during graphene growth. The graphene films characteristics depending on the substrates and the influence of synthesis process parameters such as initial amorphous carbon (a-C) thickness, laser energy and annealing temperature on the growth of graphene are discussed mainly based on Raman analysis. Investigations of electrochemistry properties of nitrogen-doped graphene synthesized by PLD are emphasized. The results show that functionalized electrodes with nitrogen-doped graphene exhibit excellent reversibility, close to the theoretical value of 59 mV, and very high sensitivity to hydrogen peroxide oxidation [3]. The present talk will help researchers to get an overview of the interest of PLD for graphene and doped-graphene synthesis.References1.Y. Bleu, F. Bourquard, T. Tite, A.-S. Loir, C. Maddi, C. Donnet, F. Garrelie, Frontier in Chemistry, 2018, 6, 572.2.C. Maddi, F. Bourquard, V. Barnier, J. Avila, M.-C. Asensio, T. Tite, C Donnet, F. Garrelie, Scientific Reports, 2018, 8, 3247.3.F. Bourquard, Y. Bleu, A.-S. Loir, B. Caja-Munoz, J. Avila, M.-C. Asensio, G. Raimondi, M. Shokouhi, I. Rassas, C. Farre, C. Chaix, V. Barnier, N. Jaffrezic-Renault, F. Garrelie, C. Donnet, Materials, 2019, 12, 666.

International audience; Carbon-based materials represent an attractive prospective in fuel cell, electrochemical and biosensors applications [1]. Recently, nitrogen doped carbon materials have raised attention in research and development to enhance their practical applications. Especially, the direct controllable nitrogen doping in graphene synthesis routes have been an attracting area of research in catalysis and sensor applications [2,3]. Here, we present the direct growth of N doped graphene from ultrashort-pulsed laser deposition technique, based on previous works related to direct synthesis of graphene [4]. The N doped graphene has been synthesized by femtosecond pulsed laser deposition and characterized by different characterization techniques to study microstructural, surface morphology and chemical bonding information. The Multi-wavelength Raman spectroscopy confirms the doping in graphene network. The nitrogen doping in graphene decreases the 2D band intensity and the correlation length. The Raman mapping has confirmed the homogenous doping of nitrogen in the graphene network. By doping, the G peak is blue shifted by 4 cm-1 and the 2D peak is red shifted by 5 cm-1; which corresponds to the n-type doping behaviour and could open a bandgap in the graphene. The surface morphology has been studied by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The films shows the layered type structures and the low roughness values were estimated in both graphene and N doped graphene. The chemical composition and bonding have been studied by X-ray Photoelectron Spectroscopy (XPS), the nitrogen doping was estimated 3 at.%. The C1s spectra shifted to higher binding energy and the N1s spectra revealed three bonding structures, which are assigned to pyridinic-N, pyrrolic-N and graphitc-N type. The pyridinic-N dominance is high in our N doped graphene. The pyridinic-N dominance N doped graphene is attractive as a catalyst in Oxygen Reduction Reactions (ORR) to enhance their applications in fuel cells and electrochemical sensors. Compared to other carbon-based electrodes, N doped graphene will be a better electrode in electrochemical sensors. It can be used for the detection of hazardous pollutants and bio-pathogens at low concentrations.References(1) Fortgang, P.; Tite, T.; Barnier, V.; Zehani, N.; Maddi, C.; Lagarde, F.; Loir, A.-S.; Jaffrezic-Renault, N.; Donnet, C.; Garrelie, F.; et al. Robust Electrografting on Self-Organized 3D Graphene Electrodes. ACS Appl. Mater. Interfaces 2016, 8, 1424–1433.(2) Wu, J.; Ma, L.; Yadav, R. M.; Yang, Y.; Zhang, X.; Vajtai, R.; Lou, J.; Ajayan, P. M. Nitrogen-Doped Graphene with Pyridinic Dominance as a Highly Active and Stable Electrocatalyst for Oxygen Reduction. ACS Appl. Mater. Interfaces 2015, 7, 14763–14769.(3) Wang, Y.; Shao, Y.; Matson, D. W.; Li, J.; Lin, Y. Nitrogen-Doped Graphene and Its Application in Electrochemical Biosensing. ACS Nano 2010, 4, 1790–1798.(4) Tite, T.; Donnet, C.; Loir, A.-S.; Reynaud, S.; Michalon J.-Y.; Vocanson, F.; Garrelie, F.; Graphene-based textured surface by pulsed laser deposition as a robust platform forsurface enhanced Raman scattering applications. Applied Physics Letters 104 (2014) 041912-1 – 0419012-4.

International audience; This study reports the comparative investigation of graphene films prepared on Si (100) and SiO2 by combining pulsed laser deposition and rapid thermal annealing using Ni catalyst. The effect of substrate and growth temperatures (600-1000°C) on the formation of graphene films was investigated by Raman spectroscopy, mapping and scanning electron microscopy (SEM). It was found that graphene films formed on Si (100) is multilayered with the formation of various nickel silicides depending on the growth temperature, while graphene films prepared on SiO2 are predominant bi- and trilayered graphene with no nickel silicide formation. The analysis of the Raman D, G and 2D peaks intensities and positions as a function of the growth temperature showed a complete opposite evolution between Si (100) and SiO2 substrates. These findings contribute to a better understanding of the combination between the nature of the substrate and the growth temperature, when growing graphene films from solid carbon source with nickel catalyst on both Si(100) and SiO2 substrates. Such a good comprehension of the substrate impact is vital for potential applications and device fabrication of graphene.

International audience; Amorphous carbon nitride (a-C:N) material has attracted much attention in research and development [1]. Recently, it has become a more promising electrode material than conventional carbon based electrodes in electrochemical and biosensor applications [2]. Nitrogen containing amorphous carbon (a-C:N) thin films have been deposited by femtosecond pulsed laser deposition (fs-PLD) coupled with plasma assistance. During the deposition process, various nitrogen pressures (0-50 Pa) and Direct Current (DC: 0-400 V) biases were used in order to introduce a wide range of nitrogen content into the films. The ablated carbon plume expansion has been investigated by ICCD gated Optical emission spectroscopy (OES) and direct 2D spectral imaging under N2 gas and DC plasma assistance. The structure and chemical composition of the films have been studied by using Multi-wavelength (MW) Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), Electron energy loss spectroscopy (EELS) and Reflection electron energy loss spectroscopy (REELS). While deposition, the intensity of the reactive activated species in the plasma plume is increased with DC biased assistance as compared to the bare N2 atmosphere, which was confirmed by optical emission spectroscopy, those deposition conditions induce an overall increase of nitrogen content in films up to 28 at.% and the formation of sp2 rich graphitic-like structures. Electrochemical properties have been investigated by cyclic voltammetry (CV) measurements to choose innovative electrode material for sensor applications. The a-C:N films show better electron transfer kinetics and excellent reproducibility than the pure a-C films. This study reveals the a-C:N films could be a promising electrode material in electrochemical detection of traces of pollutants and bio pathogen molecules. It is expected to be an alternative to BDD electrode in the near future

International audience; Graphene and doped graphene materials new synthesis routes are an attractive prospective. Especially, nitrogen doping has been an effective way to tailor the properties of graphene and make them attractive in a wide range of potential applications [1]. Recently, pulsed laser deposition of graphene has been shown to be effective in electrochemistry and biosensors applications [2]. This work reports graphene and N-doped graphene synthesis by femtosecond pulsed laser deposition. The nitrogen doping and structural changes have been studied systematically by various characterization techniques. The X-ray photoelectron spectroscopy has been performed to elucidate the C-N bonding information and N content in doped graphene. Doping of graphene decreased the 2D peak intensity compared to the pure graphene, and Raman mapping confirmed that the doping is homogeneous. The crystalline size (La) of N-doped graphene decreased with doping. The N atoms are evidenced by XPS to mainly pyridinic-N type nitrogen structure, with a N doping content up to 3 at.%. The surface morphology of films was studied by Scanning electron microscopy and Atomic force microscopy. This simple, fast and low temperature approach offers directly pyridinic-type of N bonding with high N content. This type of grown N-doped graphene could be a promising material in electrochemical sensors, electrochemical energy devices, bioelectronics and biosensors applications.

International audience; Graphene and its derivative are attracting a lot of attention today due to their growing range of applications. This highlights the need to look for new synthesis routes, which allow better tailoring of graphene based materials properties as well as simplifying synthesis methods. In particular, nitrogen doping appears as an interesting option to modify the electrochemical properties of graphene. Meanwhile, the pulsed laser deposition of graphene proved efficient to produce multilayer graphene for applications in the domain of biosensors. In this work, N-doped graphene synthesis was performed through femtosecond pulsed laser ablation of graphite in a nitrogen environment, and vacuum annealing of the depositedmaterial. Nitrogen doping and structural properties of the material were evaluated via different characterization techniques. C-N bonding configurations as well as N contents have been evaluated by X-ray photoelectron spectroscopy. Raman mapping showed the decrease of the 2D peak intensity compared to pure graphene, as well as a decrease in crystalline size (La), allowing to check the homogeneity of the doping. XPS studies showed that N atoms appear to be mainly in the pyridinic type of bonding, with contents going up to 3 % atomic. This kind of bonding, coupled with the versatility of this fast and low temperature approach, make the produced N-doped graphene a promising materials for electrochemichal sensors, targeting biosensors applications.

International audience; The introduction of dopants, such as boron, into the graphene network, is essential for many applications (electrochemistry, sensors, photovoltaics, catalysis, etc.). Many preparation routes have been investigated for B-doped graphene (BG) films: CVD, chemical reactions between graphene or graphene oxide with boron precursors, hydrothermal and solvothermal processes, arc discharge, high temperature sublimation of highly B-doped SiC and B4C thermal decomposition. Another way consists in pulsed laser co-ablation of C and B solid sources followed by rapid thermal heating of the B-doped carbon film deposited on a metal catalyst, to obtain BG layers. The objective is to achieve a better control of boron concentration in the films.Here, we use for the first time pulsed laser co-ablation for the synthesis of B-doped graphene layers. Amorphous a-C:B films, containing 2%at. boron, 10 nm thick, are synthetized by nanosecond pulsed laser deposition on a Ni thin film (60 nm thick) previously deposited on a SiO2 substrate. Rapid Thermal Annealing is performed at 1100°C during 2’ with a heating rate of 15°C/s and a cooling rate of 1°C/s. Raman, XPS, FEG-SEM and AFM characterizations allow to determine the nature, composition and morphology of the BG films. The results confirm the fabrication of bi-trilayers boron doped graphene films with the same boron doping level (2%at) as the starting material. Our results pave a new way for boron doped graphene synthesis using laser processing.