Molecular bandgap engineering of bottom-up synthesized graphene nanoribbon heterojunctions

Chen, Yen-Chia; Cao, Ting; Chen, Chen; Pedramrazi, Zahra; Haberer, Danny; Oteyza, Dimas G. de; Fischer, Felix R.; Louie, Steven G.; Crommie, Michael F.

doi:10.1038/nnano.2014.307

Cited by 432 publications

(417 citation statements)

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“…34 Zigzag ribbons are predicted to be metallic for all ribbon widths. First samples of small graphene nanoribbons have been synthesized recently [10][11][12][13][14][15][16][17] indicating the predicted behavior. Here, we present emulation experiments of the electronic transport through small nanoribbons with specific edges and atomically precise connections to source and drain leads.…”

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confidence: 72%

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Transport gap engineering by contact geometry in graphene nanoribbons: Experimental and theoretical studies on artificial materials

et al. 2017

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Electron transport in small graphene nanoribbons is studied by microwave emulation experiments and tight-binding calculations. In particular, it is investigated under which conditions a transport gap can be observed. Our experiments provide evidence that armchair ribbons of width 3m + 2 with integer m are metallic and otherwise semiconducting, whereas zigzag ribbons are metallic independent of their width. The contact geometry, defining to which atoms at the ribbon edges the source and drain leads are attached, has strong effects on the transport. If leads are attached only to the inner atoms of zigzag edges, broad transport gaps can be observed in all armchair ribbons as well as in rhomboid-shaped zigzag ribbons. All experimental results agree qualitatively with tight-binding calculations using the nonequilibrium Green's function method.

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confidence: 72%

“…The realization of such contact geometries may be extremely difficult in real graphene. However, considering the recent progress, [10][11][12][13][14][15][16][17] we think that this can be possible in the near future. Our microwave emulation experiments thus may be viewed as a testing ground for new concepts.…”

Section: Discussionmentioning

confidence: 99%

Transport gap engineering by contact geometry in graphene nanoribbons: Experimental and theoretical studies on artificial materials

et al. 2017

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“…In fact, a recent experimental work demonstrated working transistors with 9-and 13-AGNRs made with these techniques 22 . The methods used to synthesize these ribbons can also be used to generate complex periodic structures beyond simply armchair and zigzag nanoribbons 23,24 . In this work, we will consider one of those structures, the chevron graphene nanoribbon (CGNR).…”

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confidence: 99%

Negative Differential Resistance and Steep Switching in Chevron Graphene Nanoribbon Field-Effect Transistors

Smith

Llinas

Bokor

et al. 2018

IEEE Electron Device Lett.

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Ballistic quantum transport calculations based on the non-equilbrium Green's function formalism show that field-effect transistor devices made from chevron-type graphene nanoribbons (CGNRs) could exhibit negative differential resistance with peak-to-valley ratios in excess of 4800 at room temperature as well as steepslope switching with 6 mV/decade subtheshold swing over five orders of magnitude and ON-currents of 88 µA µm −1 . This is enabled by the superlattice-like structure of these ribbons that have large periodic unit cells with regions of different effective bandgap, resulting in minibands and gaps in the density of states above the conduction band edge. The CGNR ribbon used in our proposed device has been previously fabricated with bottom-up chemical synthesis techniques and could be incorporated into an experimentally-realizable structure.In 1970, L.Esaki and R. Tsu predicted 1 that in an appropriately made superlattice, it should be possible to obtain very narrow width bands, which could then lead to negative differential resistance. The remarkable property of these superlattices is in the fact that, unlike the Esaki diodes, this negative differential resistance does not need any tunneling, rather it comes from the direct conduction of electrons. Nonetheless, significant difficulty in synthesizing atomically precise, eptiaxial heterostructures has made it very challenging to realize such superlattice structures 2-8 . Much work has been done on modeling graphene nanoribbon heterostructures and superlattices which could exhibit NDR 9-15 . Other work has been done on steep slope devices based on GNR and CNT heterojunctions 16,17 . Gnani et al. showed how superlattices could be used in a III-V nanowire FET to achieve steep slope behavior by using the superlattice gap to filter high energy electrons in the OFF state 18 . Here, we show that the recently synthesized chevron nanoribbons 19 provides a natural, monolithic material system where narrow-width energy bands and negative differential resistance (NDR) can be achieved. Our atomistic calculations predict that the NDR behavior should manifest at room temperature along with sub-thermal steepness (<60 mV/decade at room temperature). Such NDR behavior could lead to completely novel devices for next generation electronics.Unlike a graphene sheet, a narrow strip etched out of graphene, often called a graphene nanoribbon (GNR), can provide a sizeable bandgap. As a result, GNRs could lead to devices with good ON/OFF ratio at the nanoscale. However, a number of studies have also shown the deleterious effect of edge roughness on the device performance 20,21 . Recent breakthroughs in bottom-up chemical synthesis can produce GNRs with atomistically pristine edge states and overcome this shortcoming 19 . In fact, a recent experimental work demonstrated working transistors with 9-and 13-AGNRs made with these techniques 22 . The methods used to synthesize these ribbons can also be used to generate complex periodic structures beyond simply armchair and zigzag nanoribbon...

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“…Since the discovery of graphene [1,2], this one-atom thick honeycomb lattice has been investigated intensely in both the experimental and theoretical scientific studies because of its high electron mobility, large accessible surface area, excellent mechanical strength, thermal and optical properties [3][4][5][6][7][8]. It has shown potential applications in many areas such as nanoelectronics, catalysis, and batteries, supercapacitors, and sensors, etc [9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Non-covalent functionalization of CVD-grown graphene with Au nanoparticles for electrochemical sensing application

Shown

Ganguly

2016

J Nanostruct Chem

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Graphene is an one-atom thick two-dimensional (2D) transparent carbon sheet which has aroused potential interest for the ultrafast high-sensitive electronic device application. Functionalization of 2D graphene is one of the important aspects to manipulate its intrinsic properties achieving the requisite aptness for its booming applications. Here, a novel strategy for the noncovalent surface functionalization of 2D graphene layer has been proposed utilizing self-assemble monolayers (SAM) of 1,4-benzenedimethanethiol (BDMT) that can further anchor gold nanoparticles (AuNPs) on the graphene surface. Raman spectroscopy and contact angle measurements confirm the SAM modification on graphene surface. AFM and XPS verify the anchoring of AuNPs on the graphene surface. Furthermore, the AuNPs-anchored BDMT-modified graphene (AuNPs/BDMT/G) electrode is explored for highly sensitive electrochemical detection of H 2 O 2 , exhibiting an impressive detection limit of 1.8 lM (signal-to-noise ratio of 3).Electronic supplementary material The online version of this article

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Molecular bandgap engineering of bottom-up synthesized graphene nanoribbon heterojunctions

Cited by 432 publications

References 31 publications

Transport gap engineering by contact geometry in graphene nanoribbons: Experimental and theoretical studies on artificial materials

Transport gap engineering by contact geometry in graphene nanoribbons: Experimental and theoretical studies on artificial materials

Negative Differential Resistance and Steep Switching in Chevron Graphene Nanoribbon Field-Effect Transistors

Non-covalent functionalization of CVD-grown graphene with Au nanoparticles for electrochemical sensing application

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