Gigahertz Integrated Graphene Ring Oscillators

Guerriero, Erica; Polloni, Laura; Bianchi, Massimiliano; Behnam, Ashkan; Carrion, Enrique; Rizzi, Laura Giorgia; Pop, Eric; Sordan, Roman

doi:10.1021/nn401933v

Cited by 74 publications

(83 citation statements)

References 41 publications

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“…An important use of ROs is as interface circuits for wireless sensor systems 37 . For this application, frequency sensitivity is defined as the voltage-dependent variation of f o , and this sensitivity is used to characterize the performance of the interface circuit.…”

Section: Scaling Behaviour Of Cnt Rosmentioning

confidence: 99%

“…The corresponding gate delay per stage (τ) is approximately 18 ps, a value much smaller than that of the fastest ICs based on CNTs 32 (τ = 355 ps) and that of the fastest graphene-based ICs 38 (τ = 39 ps). In fact, the gate delay of the ICs based on the CNT film FETs with a L g = 115 nm sets a record among all ICs based on nanomaterials, including CNTs 20,32 , graphene 37,38 , and MoS 2 (ref. 39 ), and is even comparable to the gate delay of commercial Si CMOS ICs (τ = 11 ps) with a L g of 130 nm (ref.…”

Section: Nature Electronicsmentioning

confidence: 99%

“…For a FET based on the CNT array, the capacitance consists of two parts-the quantum capacitance and the electrostatic capacitance in series. The quantum capacitance is given by 37,39 :…”

Section: Fabrication Of Top-gate Fetsmentioning

confidence: 99%

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Gigahertz integrated circuits based on carbon nanotube films

et al. 2017

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Carbon nanotube (CNT)-based electronics are a potential candidate to replace silicon complementary metal-oxide-semiconductor (CMOS) technology, which will soon meet its performance limit at the 7 or 5 nm technology node 1,2 . Prototype device studies using individual CNTs have shown that nanotube electronics have the potential to outperform Si CMOS technology in both performance and power consumption [3][4][5][6] , and are even close to the theoretical limits for all field-effect-transistor(FET)-based binary switches 7,8 . Recently, FETs were fabricated using aligned CNT arrays, and shown to have a higher channel conductance (at a lower bias) than that of Si CMOS FETs 9 . However, the key performance metrics reported for such CNT FETs, including on-state current density (I on ) and transconductance (g m ), are still substantially lower than those of conventional Si CMOS FETs at the same characteristic length [9][10][11][12][13] . The ideal material system for high-performance CNT electronics has been identified as a parallel array film of intrinsic pure semiconductor single-walled nanotubes of a single chirality with a diameter of approximately 1.3 nm and no defects, and a tube-tube spacing of 5-8 nm (ref. 14 ). Although such an ideal material system is yet to be realized, many breakthroughs in the purification and controlled synthesis of CNTs have been made in recent years [15][16][17][18][19] , suggesting the possibility of achieving the required nanotube purity and array density before 2020 14 . Using randomly oriented or aligned CNT array films, various types of CNT thin-film FETs have been fabricated [9][10][11][12][13] . However, hindered by the limited performance of nanotube FETs, the operation speed of CNT integrated circuits (ICs) 20-31 typically falls short of their expected terahertz potential, and that achieved by Si CMOS circuits (gigahertz), by several orders of magnitude. Notably, CNT-based ring oscillators (ROs) with an oscillation frequency (f o ) of 282 MHz have recently been reported 32 . However, CNT-thin-film-based ICs typically have a working frequency of less than 1 MHz, which might be useful for flexible electronics, but is not suitable for mainstream high-performance CMOS technology 33 . In this study, we used a randomly oriented CNT film to build CNT FETs and ICs, fabricating, in particular, five-stage ROs with f o of up to 5.54 GHz. The random CNT film is essentially the same as a network film, but here we used the term 'random film' to emphasize that our FETs are contact dominated and have a different transport mechanism to that of junction-dominated network-type FETs 34,35 . In principle, aligned CNT arrays would provide better device performance, but it remains a challenge to obtain wafer-scale aligned CNT arrays with high uniformity, high density and high semiconductor purity for constructing high-performance ICs. Although it is not the ideal scheme, the FET-and IC-based random CNT film can nevertheless provide a feasible demonstration to assess the floor-level performance (f...

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Section: Scaling Behaviour Of Cnt Rosmentioning

confidence: 99%

Section: Nature Electronicsmentioning

confidence: 99%

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Gigahertz integrated circuits based on carbon nanotube films

et al. 2017

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“…Following the achievement of impressive GHz cut-off frequency for graphene transistors [2][3][4], a number of applications in RF electronics have been reported which include frequency mixers and multipliers [5][6][7] and oscillators [8]. Equally, a graphene based integrated circuit consisting of active and passive components in the signal amplification, filtering and downconversion mixing units has been demonstrated [9].…”

Section: Introductionmentioning

confidence: 99%

A circuit model for defective bilayer graphene transistors

Umoh

Moktadir

Hang

et al. 2016

Solid-State Electronics

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a b s t r a c tThis paper investigates the behaviour of a defective single-gate bilayer graphene transistor. Point defects were introduced into pristine graphene crystal structure using a tightly focused helium ion beam. The transfer characteristics of the exposed transistors were measured ex-situ for different defect concentrations. The channel peak resistance increased with increasing defect concentration whilst the on-off ratio showed a decreasing trend for both electrons and holes. To understand the electrical behaviour of the transistors, a circuit model for bilayer graphene is developed which shows a very good agreement when validated against experimental data. The model allowed parameter extraction of bilayer transistor and can be implemented in circuit level simulators.

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“…(4)(5)(6) The combination of four features in the 2D chalcogenides lays the foundation for technologically viable atomic electronics. First, the intrinsic semiconducting nature, contrasting graphene's metallicity, (7)(8)(9)(10)(11)(12)(13)(14) enables high on/off current ratios, a basic requirement for logic operation. Second, the planar 2D structure offers compatibility to optical lithography and large-scale fabrication, rivaling 1D nanostructures such as carbon nanotubes.…”

Section: Introductionmentioning

confidence: 99%

Carrier Injection and Scattering in Atomically Thin Chalcogenides

Tsukagoshi

2015

J. Phys. Soc. Jpn.

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Atomically thin two-dimensional chalcogenides such as MoS 2 monolayers are structurally ideal channel materials for the ultimate atomic electronics. However, a heavy thickness dependence of electrical performance is shown in these ultrathin materials, and the device performance normally degrades while exhibiting a low carrier mobility as compared with corresponding bulks, constituting a main hurdle for application in electronics. In this brief review, we summarize our recent work on electrode/channel contacts and carrier scattering mechanisms to address the origins of this adverse thickness dependence.Extrinsically, the Schottky barrier height increases at the electrode/channel contact area in thin channels owing to bandgap expansion caused by quantum confinement, which hinders carrier injection and degrades device performance.Intrinsically, thin channels tend to suffer from intensified Coulomb impurity scattering, resulting from the reduced interaction distance between interfacial impurities and channel carriers. Both factors are responsible for the adverse dependence of carrier mobility on channel thickness in two-dimensional semiconductors.

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Gigahertz Integrated Graphene Ring Oscillators

Cited by 74 publications

References 41 publications

Gigahertz integrated circuits based on carbon nanotube films

Gigahertz integrated circuits based on carbon nanotube films

A circuit model for defective bilayer graphene transistors

Carrier Injection and Scattering in Atomically Thin Chalcogenides

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