Laser technologies for the development of carbon materials for environmental analytical microsystems

• Main Author: Maddi, Chiranjeevi
• Other Authors: Lyon
• Language: en
• Published: 2016
• Subjects: Lasers ultracourts; Dépôt par laser pulsé; Matériaux à base de carbone; Nitrure de carbone amorphe; Graphène dopé; Composition structurelle et chimique; Electrochimie; Détection et fonctionnalisation; Ultrashort lasers; Pulsed laser deposition; Carbon based materials; Amorphous carbon nitride; N doped graphene; Structural and chemical composition; Electrochemistry; Detection and functionalization
• Online Access: http://www.theses.fr/2016LYSES014/document

Technologies laser pour l’élaboration de matériaux carbonés pour microsystèmes analytiques environnementaux. Pas de résumé en français fourni === Amorphous carbon nitride (a-CzN) material has attractor much attention in research and development. Recently, it has become a more promising electrode material than conventional carbon based electrodes in electrochemical and biosensor applications. Nitrogen containing amorphous carbon (a-C:N) thin films have been synthesized by femtosecond pulsed laser deposition (fs-PLD) coupled with plasma assistance through Direct Current (DC) bias power supply. During the deposition process, various nitrogen pressures (0 to 50 Pa) and DC bias (0 to -350 V) were used in order to explore a wide range of nitrogen content into the film. The structure and chemical composition of the films have been studied by using Multi-wavelength (MW) Roman spectroscopy, electron energy-loss spectroscopy (EELS), X-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy (HRTBM). The surface morphology has been studied by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Increasing the nitrogen pressure or adding a DC bias induced an increase of the N content, up to 28 at.%. Nitrogen content increase induces a higher sp2 character of the film. However DC bias has been found to increase the film structmal disorder, which was detrimental to the electrochemical properties. Indeed the electrochemical measurern-ts, investigated by cyclic voltammetry (CV), demonstrated that the a-CzNfilms show better electron transfer kinetics, reversibility and excellent reproducibility than the pure a-C films. Electrochemical grafting from diazoniurn salts was successfully achieved on this film, with a surface coverage of covalently bonded molecules close to the dense packed monolayer of ferrocene