Chemical vapor deposition (CVD) has been demonstrated as a highly promising technique for the production of graphene on large scale and enabling tunability of the intrinsic defects of the films during the synthesis.

In this work, we report on the correlation between the density of defects (DoD) and the kinetics of interaction of multi-layered graphene (MLG) with nitrogen dioxide (NO2) used as a target gas. We grow MLG on a pre-patterned molybdenum (Mo) catalyst layer, tailoring the DoD while growing MLG at temperatures from 850 °C to 980 °C. Analysing the Raman spectra, we show the lowering of the DoD as well as a quality dependence of MLG as a function of the growth temperature. The chemi-resistors based on MLG grown at different temperatures unambiguously highlight that, both during the exposure and the subsequent purge phase, the more defective the MLG, the more intense the NO2’s molecules interaction with MLG. Our results significantly mark a step forward in tuning the sensing properties of MLG without the need of any post-processing of the material after synthesis.@en

Humidity sensing is fundamental in some applications, as humidity can be a strong interferent in the detection of analytes under environmental conditions. Ideally, materials sensitive or insensitive towards humidity are strongly needed for the sensors used in the first or second case, respectively. We present here the sensing properties of multi-layered graphene (MLG) upon exposure to different levels of relative humidity. We synthesize MLG by chemical vapor deposition, as shown by Raman spectroscopy, Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). Through an MLG-based resistor, we show that MLG is scarcely sensitive to humidity in the range 30%–70%, determining current variations in the range of 0.005%/%relative humidity (RH) well below the variation induced by other analytes. These findings, due to the morphological properties of MLG, suggest that defective MLG is the ideal sensing material to implement in gas sensors operating both at room temperature and humid conditions.

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The unique properties and atomic thickness of two-dimensional (2D) materials enable smaller and better nanoelectromechanical sensors with novel functionalities. During the last decade, many studies have successfully shown the feasibility of using suspended membranes of 2D materials in pressure sensors, microphones, accelerometers, and mass and gas sensors. In this review, we explain the different sensing concepts and give an overview of the relevant material properties, fabrication routes, and device operation principles. Finally, we discuss sensor readout and integration methods and provide comparisons against the state of the art to show both the challenges and promises of 2D material-based nanoelectromechanical sensing.

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All-printed transistors consisting of interconnected networks of various types of twodimensional nanosheets are an important goal in nanoscience. Using electrolytic gating, we demonstrate all-printed, vertically stacked transistors with graphene source, drain, and gate electrodes, a transition metal dichalcogenide channel, and a boron nitride (BN) separator, all formed from nanosheet networks.The BN network contains an ionic liquid within its porous interior that allows electrolytic gating in a solid-like structure. Nanosheet network channels display on:off ratios of up to 600, transconductances exceeding 5 millisiemens, and mobilities of >0.1 square centimeters per volt per second. Unusually, the on-currents scaled with network thickness and volumetric capacitance. In contrast to other devices with comparable mobility, large capacitances, while hindering switching speeds, allow these devices to carry higher currents at relatively low drive voltages.

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