Novel synthesis routes for nitrogen doped graphene and atomic level characterization

Abstract text (incl. figure legends and references)

Graphene has been subject of intense research and holds promising perspectives for future applications due to its unique properties. However, controlled structural modifications are desirable in order to fine-tune its properties, e.g. via the introduction of dopant atoms. In this work, we analyzed and compared nitrogen doping via ion implantation (as in [1]) with newly developed and experimentally very simple techniques of gas arc discharges in a nitrogen environment and plasma treatment with nitrogen plasma. For this purpose, several experimental setups were built, utilising (a) pure, energy-constrolled ion beams (b) gas discharge between the sample and a counter-electrode at pressures between 0.1 and 10 mbar (example in Figure 1), or (c) treatment inside a commercial plasma cleaner for TEM-holders.

HRTEM is used to examine the doped graphene, allowing to evaluate and compare different doping methods. HRTEM, combined with image simulations, allow identifying nitrogen impurities inside the treated graphene samples [2], as exemplified in Figure 2, and provides insight into the implantation processes. Several synthesis routes were established, giving the opportunity to either study the underlying processes of ion implantation or allowing straightforward production of nitrogen doped graphene that can be implemented quite easily.

[1] U. Bangert et al., Nano lett. 13:4902, 2013

[2] J. C. Meyer et al., Nat. Mat. 10:209, 2011