Graphene nanomesh transistor with high on/off ratio and good saturation behavior

Berrada, Salim; Nguyễn, Việt Hùng; Querlioz, Damien; Saint-Martin, Jérôme; Alarcon, A.; Chassat, C.; Bournel, A.; Dollfus, Philippe

doi:10.1063/1.4828496

Cited by 42 publications

(26 citation statements)

References 44 publications

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“…Graphene nanomesh (GNM), a graphene sheet with periodically arranged nanopores, has attracted extensive attention in recent a few years due to the promising applications in the field-effect transistors [1][2][3][4][5][6][7][8], vapor detection [9][10][11], photothermal therapy [12] and energy storage [13]. GNMs can be viewed as networks of graphene nanoribbons (GNRs), but GNMs have significantly higher on-off ratio and larger supported current than GNRs [1,14]. It has also been shown that GNMs have a strong negative differential conductance which is useful for high frequency applications [15].…”

Section: Introductionmentioning

confidence: 99%

Ultra-low thermal conductivity in graphene nanomesh

Feng

Ruan

2016

Carbon

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Graphene nanomesh (GNM), a new nanostructure of graphene, has attracted extensive interest recently due to the promising chemical, electronic and photonic applications. In this paper, another important property-thermal conductivity is systematically investigated by using molecular dynamics simulations. The thermal conductivity (κ) is found to be extremely low, up to more than 3 orders lower than the pristine single layer graphene. Roughly, κ decreases exponentially with increasing porosity and linearly with decreasing neck width, and is not temperature sensitive in the range of 300 K to 700 K. κ of GNMs is found to be even up to 200 fold lower than the graphene nanoribbons (GNR), a potential thermoelectric material, of the same neck width or boundary-to-area ratio. The extremely low κ in the GNM makes it a potential candidate for thermoelectrics. The phonon participation spectra show that the low κ in GNM is due to the localization and phonon back scattering around the nanopores. We also find that the phonon coherence in two dimensional superlattice GNM indeed exists, but is not as important as in the one dimensional superlattices. The isotope effect is negligible. The thermal conductivity reduction by edge passivation increases with increasing neck width and porosity.

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Section: Introductionmentioning

confidence: 99%

Ultra-low thermal conductivity in graphene nanomesh

Feng

Ruan

2016

Carbon

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“…First, it has been shown that by using bilayer graphene instead of single-layer material and applying a perpendicular field, a gap is formed [7,8]. A second option is to create narrow confined graphene structures, such as GNRs (graphene nanoribbon) [9,10] or graphene nanomeshes [11,12], in which a gap opens. In the present work, we focus on GNRs and use these as MOSFET channels.…”

Section: Introductionmentioning

confidence: 99%

Simulation of 50-nm Gate Graphene Nanoribbon Transistors

et al. 2016

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An approach to simulate the steady-state and small-signal behavior of GNR MOSFETs (graphene nanoribbon metal-semiconductor-oxide field-effect transistor) is presented. GNR material parameters and a method to account for the density of states of one-dimensional systems like GNRs are implemented in a commercial device simulator. This modified tool is used to calculate the current-voltage characteristics as well the cutoff frequency f T and the maximum frequency of oscillation f max of GNR MOSFETs. Exemplarily, we consider 50-nm gate GNR MOSFETs with N = 7 armchair GNR channels and examine two transistor configurations. The first configuration is a simplified MOSFET structure with a single GNR channel as usually studied by other groups. Furthermore, and for the first time in the literature, we study in detail a transistor structure with multiple parallel GNR channels and interribbon gates. It is shown that the calculated f T of GNR MOSFETs is significantly lower than that of GFETs (FET with gapless large-area graphene channel) with comparable gate length due to the mobility degradation in GNRs. On the other hand, GNR MOSFETs show much higher f max compared to experimental GFETs due the semiconducting nature of the GNR channels and the resulting better saturation of the drain current. Finally, it is shown that the gate control in FETs with multiple parallel GNR channels is improved while the cutoff frequency is degraded compared to single-channel GNR MOSFETs due to parasitic capacitances of the interribbon gates.

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“…4a and 4b is caused the saturation current, as is observed for the conductivity behavior of single carbon nanotube and graphene. [22][23][24] In the NCM523 electrode, the electronic conductivity is provided by the carbon black matrix, which has a limit due to its finite amount of free electrons. This limit current provided by the carbon black matrix is defined as a saturation current and its relation to the saturation current of the electrode can be expressed as in Equation 1.…”

Section: Resultsmentioning

confidence: 99%

Nonlinear Conductivities and Electrochemical Performances of LiNi_0.5Co_0.2Mn_0.3O₂Electrodes

Ishwait

et al. 2016

J. Electrochem. Soc.

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There is increasing research attention on optimizing the carbon black nanoparticles' structure and loading procedure for improving conductivities and thus, electrochemical performances of cathodes in lithium-ion batteries. Recently, LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM523) has been actively investigated due to its larger specific capacity and lower cost compared to conventional cathode materials. Presented here is a high energy density NCM523 cathode obtained by reducing the carbon content using the state-of-the-art carbon nanoparticles developed at Cabot Corporation. It is the first time that the nonlinear conductivity of NCM523 electrodes has been discovered, which is significantly impacted by the dispersion and surface crystalline quality of carbon black nanoparticles, especially when the loading of carbon black is only 1 wt%. The nonlinear conductivity of the cathodes can dramatically affect their electrochemical performances at high rates ( 3C), which is close to the tunneling saturated current. In addition, there is no discernable difference in terms of the rate and cycle performance of the NCM523 electrodes, when reducing the loading of novel carbon black nanoparticles from 5 wt% to 1 wt% in the cathode. Therefore, the energy density of the electrode can be increased by 9% by using existing commercially available electrode materials. In lithium-ion batteries, the active materials of the cathodes typically exhibit relatively high resistivity due to their intrinsically poor electronic conductivity and the limited point contacts between their micro particles. [1][2][3][4][5][6] In addition, the active materials need to be mixed with binders to form the electrode, which insures the mechanical integrity and stability of the electrode. However, the binders are electric insulators that can further reduce the electrical conductivity of the electrode. To minimize the problem of the poor electrical conductivity of the electrode, conductive powders, such as carbon black, carbon fiber, carbon nanotube, or graphene, are added to the electrode formulation. [5][6][7][8][9][10] In the battery industry, there are at least two competing requirements for the amount of conductive additive needed: (i) high rate performance requiring a large amount of conductive additive and (ii) high energy density dictating that the amount of conductive additive be as low as possible. These two antagonistic requirements make high demands on optimizing conductive additives as the solution. 5,6,8,10 Meanwhile, the cost is always critical for the commercial application of carbon additives. Therefore, there is increasing research attention on the carbon black nanoparticles, since it is the cheapest one among a series of carbon additives. The research focuses on the impacts of their structures, the pretreatment and loading procedures on the cathodes' performances, etc. 5,6,[10][11][12][13][14] The mechanism for the electronic conduction of carbon black nanoparticles' aggregates in cathodes is believed to occur through tunneling phenomena, the probabil...

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Graphene nanomesh transistor with high on/off ratio and good saturation behavior

Cited by 42 publications

References 44 publications

Ultra-low thermal conductivity in graphene nanomesh

Ultra-low thermal conductivity in graphene nanomesh

Simulation of 50-nm Gate Graphene Nanoribbon Transistors

Nonlinear Conductivities and Electrochemical Performances of LiNi_0.5Co_0.2Mn_0.3O₂Electrodes

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Graphene nanomesh transistor with high on/off ratio and good saturation behavior

Cited by 42 publications

References 44 publications

Ultra-low thermal conductivity in graphene nanomesh

Ultra-low thermal conductivity in graphene nanomesh

Simulation of 50-nm Gate Graphene Nanoribbon Transistors

Nonlinear Conductivities and Electrochemical Performances of LiNi0.5Co0.2Mn0.3O2Electrodes

Contact Info

Product

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Nonlinear Conductivities and Electrochemical Performances of LiNi_0.5Co_0.2Mn_0.3O₂Electrodes