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Hysteresis exhibited by current–voltage characteristics during field‐emission experiments is often considered undesirable in terms of practical applications. However, this is an appealing effect for the purposes of memristive devices. A two‐stage model to describe hysteretic characteristics is developed, with a particular focus on the system which includes a cathode made of a single‐layered graphene sheet on a substrate. In addition to hysteresis, the current–voltage curves also display an unusual self‐crossing behavior. The presented memristive model can be used for quantitative description of different hysteretic characteristics such as abrupt changes and self‐crossings and for understanding and modeling the processes associated with field emission from plane graphene emitters. [ABSTRACT FROM AUTHOR]

Graphene derivatives are promising sensor materials due to their high surface area available for molecule adsorption and conductivity changes under the adsorbate impact. The selectivity of such materials can be tuned through the attaching of certain functional groups preferably interacting with the defined gases. In the present work, we compare the reactivity of graphene oxide, oxyfluorinated graphene, and fluorinated graphene toward gaseous NOx molecules. The interaction of the molecules with the graphene‐based films was monitored by in situ X‐ray photoelectron and near‐edge X‐ray absorption fine structure spectroscopy measurements. The spectra before and after exposure of the films to a gaseous NOx mixture detected equal concentrations of adsorbed NO2 and NO species on graphene oxide, the preferable interaction of oxyfluorinated graphene with NO2 and the absence of the adsorbed molecules on the fluorinated graphene surface. These results are useful for the development of selective graphene‐based gas sensors. [ABSTRACT FROM AUTHOR]