New techniques to manipulate the electronic properties of few layer 2D materials, unveiling new physical phenomena as well as possibilities for new device applications have brought renewed interest to these systems. Therefore, the quest for reproducible methods for the large scale synthesis, as well as the manipulation, characterization and deeper understanding of these structures is a very active field of research. We here report the production of nitrogen doped bilayer graphene in a fast single step (2.5 minutes), at reduced temperatures (760 °C) using microwave plasma-enhanced chemical vapor deposition (MW-PECVD). Raman spectroscopy confirmed that nitrogen-doped bilayer structures were produced by this method. XPS analysis showed that we achieved control of the concentration of nitrogen dopants incorporated into the final samples. We have performed state of the art parameter-free simulations to investigate the cause of an unexpected splitting of the XPS signal as the concentration of nitrogen defects increased. We show that this splitting is due to the formation of interlayer bonds mediated by nitrogen defects on the layers of the material. The occurrence of these bonds may result in very specific electronic and mechanical properties of the bilayer structures.

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In this study, we combine Low Energy Ion Scattering (LEIS) static and sputter depth profiles for characterization of the oxidation kinetics on Zr, Mo, Ru and Ta films of various thicknesses, following exposure to atomic oxygen at room temperature (∼20 • C). A method for non-destructive determination of the oxide growth rate via LEIS static depth profiling (static DP) is presented in detail. This method shows high sensitivity to the oxide thickness formed, and the results are in agreement with those obtained by X-ray reflectometry (XRR) and sputter depth profiling (sputter DP). Sequential exposures of oxygen isotopes in combination with LEIS sputter DP are applied to elucidate the growth mechanism of the oxide films. The results indicate that the oxidation kinetics at the applied experimental conditions is directly influenced by the metal work function, characterizing a Cabrera-Mott growth type. The maximum thickness of the formed oxide and oxide growth rate are in the order: Zr ≈ Ta > Mo > Ru. The combining of analysis by LEIS static DP and isotope tracing sputter DP is decisive in the characterization of oxidation kinetics in the room temperature regime.

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Alle rechten voorbehouden. Niets uit deze uitgave mag worden vermenigvuldigd, in enige vorm of op enige wijze, zonder voorafgaande schriftelijke toestemming van de auteur. Acknowledgements:This work is part of the research programme of the Industrial Focus Group XUV Optics, being part of the MESA+ Institute for Nanotechnology and the University of Twente (http://www.utwente.nl/xuv). We acknowledge the support by the industrial partners Carl Zeiss SMT, ASML and Malvern Panalytical, as well as the Province of Overijssel and the Netherlands Organization for Scientific Research (NWO).To my parents, who always supported me to follow my own path, and to my grandmas, my examples of strength, independence and perseverance.

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