Environmental Effects on the Electrical Characteristics of Back-Gated WSe&lt;sub&gt;2&lt;/sub&gt; Field Effect Transistors

Urban, Francesca; Martucciello, Nadia; Peters, Lisanne; McEvoy, Niall; Bartolomeo, Antonio Di

doi:10.20944/preprints201810.0095.v1

Cited by 15 publications

References 54 publications

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Air Pressure, Gas Exposure and Electron Beam Irradiation of 2D Transition Metal Dichalcogenides

et al. 2020

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In this study, we investigate the electrical transport properties of back-gated field-effect transistors in which the channel is realized with two-dimensional transition metal dichalcogenide nanosheets, namely palladium diselenide (PdSe2) and molybdenum disulfide (MoS2). The effects of the environment (pressure, gas type, electron beam irradiation) on the electrical properties are the subject of an intense experimental study that evidences how PdSe2-based devices can be reversibly tuned from a predominantly n-type conduction (under high vacuum) to a p-type conduction (at atmospheric pressure) by simply modifying the pressure. Similarly, we report that, in MoS2-based devices, the transport properties are affected by pressure and gas type. In particular, the observed hysteresis in the transfer characteristics is explained in terms of gas absorption on the MoS2 surface due to the presence of a large number of defects. Moreover, we demonstrate the monotonic (increasing) dependence of the width of the hysteresis on decreasing the gas adsorption energy. We also report the effects of electron beam irradiation on the transport properties of two-dimensional field-effect transistors, showing that low fluences of the order of few e-/nm2 are sufficient to cause appreciable modifications to the transport characteristics. Finally, we profit from our experimental setup, realized inside a scanning electron microscope and equipped with piezo-driven nanoprobes, to perform a field emission characterization of PdSe2 and MoS2 nanosheets at cathode–anode separation distances as small as 200 nm.

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Air Pressure, Gas Exposure and Electron Beam Irradiation of 2D Transition Metal Dichalcogenides

et al. 2020

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A Peculiar Binding Characterization of DNA (RNA) Nucleobases at MoOS-Based Janus Biosensor: Dissimilar Facets Role on Selectivity and Sensitivity

et al. 2022

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Distinctive properties of Janus monolayer have drawn much interest in biotechnology applications. For this purpose, it has explored theoretically all sensing possibilities of nucleobases molecules (DNA/RNA) by Janus MoOS monolayer on both oxygen and sulfur terminations by means of rigorous first–principles calculation. Indeed, differences in interaction energy between nucleobases indicate that a monolayer can be used for DNA sequencing. Exothermic interaction energy range for DNA/RNA molecules with both oxygen and sulfur sides of the Janus MoOS surfaces have been found to range between (0.61–0.91 eV), and (0.63–0.88 eV), respectively, and the binding distances indicate that these molecules bind to both facets by physisorption. The exchange of weak electronic charges between the MoOS monolayer and the nucleobases molecules has been studied by means of Hirshfeld-I charge analysis. It has been observed that the introduction of DNA/RNA nucleobases molecules alters the electronic properties of both oxygen and sulfur atomic layers of the Janus MoOS complex systems as determined by plotting the 3D Kohn–Sham frontier orbitals. A good correlation has been found between the interaction energy, van der Waals energy, Hirshfeld-I, and d–band center as a function of the nucleobase’s affinity, and the interaction energy, suggesting adsorption dominated by van der Waals interactions driven by molybdenum d–orbital. Moreover, the lowering in the adsorption energy leads to an active interaction of the DNA/RNA with the surfaces, accordingly its conduct to shorter the recovery time. The selectivity of the biosensor modulation device has illustrated a significant sensitivity for the nucleobases on both the oxygen and sulfur layer sides of the MoOS monolayer. This finding reveals that apart from graphene, dichalcogenides–Janus transition metal may also be adequate for identifying DNA/RNA bases in applied biotechnology.

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Electrical Conduction and Photoconduction in PtSe2 Ultrathin Films

Bartolomeo

Urban

Faella

et al. 2020

The 2nd International Online-Conference on Nanomaterials

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We report the characterization of back-gated field-effect transistors fabricated using platinum diselenide (PtSe2) ultrathin films as a channel. We perform a detailed study of the electrical conduction as well as of the photoconductivity. From the gate modulation of the channel current, we obtain the signature of p-type semiconducting conduction with carrier mobility of about 30 cm2 V−1 s−1. More interestingly, PtSe2 devices exposed to light, either in air and in vacuum, exhibit negative photoconductivity, which we explain by a photogating effect due to charge trapping in the gate dielectric and light-induced desorption of adsorbates.

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Environmental Effects on the Electrical Characteristics of Back-Gated WSe<sub>2</sub> Field Effect Transistors

Cited by 15 publications

References 54 publications

Air Pressure, Gas Exposure and Electron Beam Irradiation of 2D Transition Metal Dichalcogenides

Air Pressure, Gas Exposure and Electron Beam Irradiation of 2D Transition Metal Dichalcogenides

A Peculiar Binding Characterization of DNA (RNA) Nucleobases at MoOS-Based Janus Biosensor: Dissimilar Facets Role on Selectivity and Sensitivity

Electrical Conduction and Photoconduction in PtSe2 Ultrathin Films

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