Fabrication and characterization of nanometer-sized gaps in suspended few-layer graphene devices

Lumetti, Stefano; Martini, Leonardo; Candini, Andrea

doi:10.1088/1361-6641/32/2/024002

Cited by 7 publications

(4 citation statements)

References 45 publications

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“…The graphene/MoS 2 junction, by contrast, shows a different behavior with a usual metal/semiconductor junction along the gate voltage ( V gs ) (black and blue closed dots in Figure j). The SBH of the graphene/MoS 2 junction gradually decreases from 130 to −40 meV without a saturation region as the gate voltage increases from −0.5 to 4 V, which is largely attributed to a modulation of the Fermi levels ( E F ) − of the graphene along the gate voltage (Figure i). A negative gate voltage increases the SB by downshifting the graphene E F , resulting in a suppression of the electron transport across the graphene/MoS 2 interface (Figure i, left panel).…”

Section: Resultsmentioning

confidence: 96%

Schottky Barrier Variable Graphene/Multilayer-MoS₂ Heterojunction Transistor Used to Overcome Short Channel Effects

Lee

Kim

Kang

et al. 2019

ACS Appl. Mater. Interfaces

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A single-layer MoS 2 achieves excellent gate controllability within the nanoscale channel length of a fieldeffect transistor (FET) owing to an ultra-short screening length. However, multilayer MoS 2 (ML-MoS 2 ) is more vulnerable to short channel effects (SCEs) owing to its thickness and long screening length. We eliminated the SCEs in an ML-MoS 2 FET (thickness of 4−13 nm) at a channel length of sub-30 nm using a Schottky barrier (SB) variable graphene/ML-MoS 2 heterojunction. Although the band modulation in the ML-MoS 2 channel worsens with a decrease in the channel length, which is similar to the SCEs occurring in conventional FETs, the variable Fermi level (E F ) of a graphene electrode along the gate voltage allows control of the SB at the graphene/MoS 2 junction and backs up the current modulation through a variable SB. Electrical measurements and a theoretical band simulation demonstrate the efficient SB modulation of our graphene nanogap (GrNG) ML-MoS 2 FET with three distinct carrier transports along V gs : a thermionic emission at a low SB, Fowler−Nordheim tunneling at a moderate SB, and direct tunneling at a high SB. Our GrNG FET shows an extremely high on−off current ratio of ∼10 8 , which is approximately threeorders of magnitude better than a previously reported metal nanogap (MeNG) FET and a self-aligned metal/graphene nanogap FET with a similar MoS 2 thickness. Our GrNG FET also exhibits a 100,000-times higher on−off ratio, 100-times lower subthreshold swing, and 10-times lower drain induced barrier.

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Section: Resultsmentioning

confidence: 96%

Schottky Barrier Variable Graphene/Multilayer-MoS₂ Heterojunction Transistor Used to Overcome Short Channel Effects

Lee

Kim

Kang

et al. 2019

ACS Appl. Mater. Interfaces

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“…In particular, in the recent experimental literature there are examples demonstrating that the exceptional degree of control at the atomistic scale required by the proposed device is not far. Indeed the present nanotechnology allow the realization of graphene nano-gaps down to the sub-nanometer size 11,24,[29][30][31] and the synthesis, by bottom-up strategies, of narrow GNRs 32,33 of similar size as the one here supposed (but slightly wider GNRs could be employed as well). However the needed full atomistic control at the sub-nanometer length scale required to build such a device is still challenging presently.…”

Section: Introductionmentioning

confidence: 89%

Peptide bond detection via graphene nanogaps: a proof of principle study

et al. 2018

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Solid-state nanopores and nanogaps are emerging as promising tools for single molecule analysis. 2D materials, such as graphene, can potentially reach the spatial resolution needed for nucleic acid and protein sequencing. In the context of the density functional theory, atomistic modeling and non-equilibrium Green's function calculation, we show that glycine based polypeptide chains translocating across a nano-gap between two semi-infinite graphene nano-ribbons leave a specific transverse current signature for each peptide bond. The projected density of states and bond current analyses reveal a complex scenario with a role played by the adjacent α-carbons and side chains and by the orbitals of the partially resonant double bond involving C, N and O atoms of the peptide bond. In this context, specific fingerprints of the atoms involved in the peptide bonds are found. The same scenario is evidenced also for peptides involving alanine residues. The signal measured can be considered as a specific fingerprint of peptide bonds between small and neutral amino acids with no polar/charge effects. On this basis, a newly conceived nano-device made of a graphene based array of nano-gap is proposed as a possible route to approach peptide sequencing with atomic resolution.

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“…After this procedure, the device behaves as an "open" circuit and no signature of tunnelling current is observed up to a voltage bias VSD = 2 V, ( Figure 2c), implying that the gap width is at least ~10 nm [41] . We stress that the absence of tunnelling current is fundamental to correctly assess the electrical signal arising from the GNRs contacting the graphene electrodes and not simply from tunnelling between nanometer-spaced electrodes [42] .…”

Section: Figure 1 Schematic View Of Our Devices: Metal (Cr/au) Electrmentioning

confidence: 99%

Structure-dependent electrical properties of graphene nanoribbon devices with graphene electrodes

Martini

Chen

Mishra

et al. 2019

Carbon

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Graphene nanoribbons (GNRs) are a novel and intriguing class of materials in the field of nanoelectronics, since their properties, solely defined by their width and edge type, are controllable with high precision directly from synthesis. Here we study the correlation between the GNR structure and the corresponding device electrical properties. We investigated a series of field effect devices consisting of a film of armchair GNRs with different structures (namely width and/or length) as the transistor channel, contacted with narrowly spaced graphene sheets as the source-drain electrodes. By analyzing several tens of junctions for each individual GNR type, we observe that the values of the output current display a width-dependent behavior, indicating electronic bandgaps in good agreement with the predicted theoretical values. These results provide insights into the link between the ribbon structure and the device properties, which are fundamental for the development of GNR-based electronics.

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Fabrication and characterization of nanometer-sized gaps in suspended few-layer graphene devices

Cited by 7 publications

References 45 publications

Schottky Barrier Variable Graphene/Multilayer-MoS₂ Heterojunction Transistor Used to Overcome Short Channel Effects

Schottky Barrier Variable Graphene/Multilayer-MoS₂ Heterojunction Transistor Used to Overcome Short Channel Effects

Peptide bond detection via graphene nanogaps: a proof of principle study

Structure-dependent electrical properties of graphene nanoribbon devices with graphene electrodes

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Fabrication and characterization of nanometer-sized gaps in suspended few-layer graphene devices

Cited by 7 publications

References 45 publications

Schottky Barrier Variable Graphene/Multilayer-MoS2 Heterojunction Transistor Used to Overcome Short Channel Effects

Schottky Barrier Variable Graphene/Multilayer-MoS2 Heterojunction Transistor Used to Overcome Short Channel Effects

Peptide bond detection via graphene nanogaps: a proof of principle study

Structure-dependent electrical properties of graphene nanoribbon devices with graphene electrodes

Contact Info

Product

Resources

About

Schottky Barrier Variable Graphene/Multilayer-MoS₂ Heterojunction Transistor Used to Overcome Short Channel Effects

Schottky Barrier Variable Graphene/Multilayer-MoS₂ Heterojunction Transistor Used to Overcome Short Channel Effects