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2014-02-11 - Colloque/Présentation - communication orale - Anglais - 1 page(s)

Scardamaglia Mattia, Aleman Llorente Belen, Amati Matteo, Ewels C, Pochet Pascal, Reckinger N., Colomer Jean-François, Skaltsas Theodosis, Tagmatarchis Nikos, Snyders Rony , Gregoratti Luca, Bittencourt Carla , "Heavily nitrogen-doped suspended graphene flakes: annealingeffects and selectivity of sp2 nitrogen species" in Towards Reality in Nanoscale Materials VII, Levi, Finland, 2014

  • Codes CREF : Physique de l'état solide (DI1261), Physique des plasmas (DI1233)
  • Unités de recherche UMONS : Chimie des interactions plasma-surface (S882)
  • Instituts UMONS : Institut de Recherche en Science et Ingénierie des Matériaux (Matériaux)
  • Centres UMONS : Centre d’Innovation et de Recherche en Matériaux Polymères (CIRMAP)

Abstract(s) :

(Anglais) One of the main research interests and a key challenge for nano-device fabrication is the fine tuning of graphene electronic properties [1]. Notably the low carrier density in pristine graphene at the Fermi level means that charge carrier doping, either via external molecular funtionalities or direct lattice substitutions with hetero atoms, is very attractive for nanoelectronics applications [2]. Among these, the introduction of nitrogen atoms into the hexagonal carbon lattice of graphene has attracted interest in the recent years both from an experimental [3] and a theoretical point of view [4]. Within this context, we present an experimental report that combines scanning photoemission microscopy analysis with in-situ nitrogen ion casting on suspended graphene. Nitrogen doping of both chemical vapour deposition and exfoliated graphene flakes was performed by N$^{+}_{2}$ ion bombardment in ultra-high vacuum. Inclusion of up to almost 20 at $\%$ nitrogen can be reached through this clean technique with absence of oxygen species in the final product, while maintaining a largely sp$^2$-carbon network. The inclusion was observed by scanning X-ray photoelectron microscopy which can be used to follow the evolution of nitrogen species: pyridinic, graphitic, and pyrrolic, at different doping stages and annealing temperatures. Variations in the ratio between sp$^2$ nitrogen species was observed for increasing treatment time; annealing results in quenching of the sp$^3$ component, suggesting graphitic nitrogen as the most thermal stable species. The occurrence of graphitic species together with the absence of pyrrolic is indicative of N-incorporation into a hexagonal graphene-based lattice. [1]A. K. Geim, Graphene: Status and Prospects. Science 2009, 324, 1530–4. [2]I. Gierz, C. Riedl, U. Starke, C. R. Ast, K. Kern, Atomic Hole Doping of Graphene. Nano Lett. 2008, 8, 4603–7. [3]B. Guo, Q. Liu, E. Chen, H. Zhu, L. Fang, J. R. Gong, Controllable N-Doping of Graphene. Nano Lett. 2010, 10, 4975–4980. [4]E. H. \AA hlgren, J. Kotakoski, A. V. Krasheninnikov, Atomistic simulations of the implantation of low-energy boron and nitrogen ions into graphene. Phys. Rev. B 2011, 83, 115424.