Ambipolar MoS<sub>2</sub> Thin Flake Transistors

Zhang, Yijin; Ye, Jianting; Matsuhashi, Yusuke; Iwasa, Yoshihiro

doi:10.1021/nl2021575

Cited by 782 publications

(743 citation statements)

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“…The demonstration of both n-and p-type transport will be useful for applications like CMOS logic and p-njunction optoelectronics. The on/off ratio was >200 in the device, but is much lower than the single-layer device described above 34 , mainly because of the off-current passing through the bulk of the flakes 41 . The transfer curves (source-drain current as a function of gate voltage) for thin-flake and bulk MoS 2 ambipolar devices are shown in Fig.…”

Section: Electrical Transport and Devicesmentioning

confidence: 66%

“…4e) to reach extremely high carrier concentrations of 1 × 10 14 cm 2 (ref. 41). The demonstration of both n-and p-type transport will be useful for applications like CMOS logic and p-njunction optoelectronics.…”

Section: Electrical Transport and Devicesmentioning

confidence: 99%

“…Other layered materials such as BN (refs 1,12,29) and oxide nanosheets 10,38 can also be mechanically exfoliated into single sheets by this method. Mechanical cleavage produces single-crystal flakes of high purity and cleanliness that are suitable for fundamental characterization [30][31][32][33] and for fabrication of individual devices 11,31,32,34,35,[39][40][41] . This method is not scalable, however, and does not allow systematic control of flake thickness and size.…”

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confidence: 99%

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Electronics and optoelectronics of two-dimensional transition metal dichalcogenides

et al. 2012

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699M any two-dimensional (2D) materials exist in bulk form as stacks of strongly bonded layers with weak interlayer attraction, allowing exfoliation into individual, atomically thin layers 1 . The form receiving the most attention today is graphene, the monolayer counterpart of graphite. The electronic band structure of graphene has a linear dispersion near the K point, and charge carriers can be described as massless Dirac fermions, providing scientists with an abundance of new physics 2,3 . Graphene is a unique example of an extremely thin electrical and thermal conductor 4 , with high carrier mobility 5 , and surprising molecular barrier properties 6,7 .Many other 2D materials are known, such as the TMDCs 8,9 , transition metal oxides including titania-and perovskite-based oxides 10,11 , and graphene analogues such as boron nitride (BN) 12,13 . In particular, TMDCs show a wide range of electronic, optical, mechanical, chemical and thermal properties that have been studied by researchers for decades 9,14,15 . There is at present a resurgence of scientific and engineering interest in TMDCs in their atomically thin 2D forms because of recent advances in sample preparation, optical detection, transfer and manipulation of 2D materials, and physical understanding of 2D materials learned from graphene.The 2D exfoliated versions of TMDCs offer properties that are complementary to yet distinct from those in graphene. Graphene displays an exceptionally high carrier mobility exceeding 10 6 cm 2 V -1 s -1 at 2 K (ref. 16) and exceeding 10 5 cm 2 V -1 s -1 at room temperature for devices encapsulated in BN dielectric layers 5 ; because pristine graphene lacks a bandgap, however, fieldeffect transistors (FETs) made from graphene cannot be effectively switched off and have low on/off switching ratios. Bandgaps can be engineered in graphene using nanostructuring [17][18][19] , chemical functionalization 20 and applying a high electric field to bilayer graphene 21 , but these methods add complexity and diminish mobility. In contrast, several 2D TMDCs possess sizable bandgaps around 1-2 eV (refs 9,14), promising interesting new FET and optoelectronic devices.TMDCs are a class of materials with the formula MX 2 , where M is a transition metal element from group IV (Ti, Zr, Hf and so on), group V (for instance V, Nb or Ta) or group VI (Mo, W and so on), and X is a chalcogen (S, Se or Te). These materials form layered structures of the form X-M-X, with the chalcogen atoms in two hexagonal planes separated by a plane of metal atoms, as shown in Fig. 1a. Adjacent layers are weakly held together to form the bulk crystal in a variety of polytypes, which vary in stacking orders and metal atom coordination, as shown in Fig. 1e. The overall symmetry of TMDCs is hexagonal or rhombohedral, and the metal atoms have octahedral or trigonal prismatic coordination. The electronic properties of TMDCs range from metallic to semiconducting, as summarized in Table 1. There are also TMDCs that exhibit exotic behaviours such as charge density waves ...

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Section: Electrical Transport and Devicesmentioning

confidence: 66%

Section: Electrical Transport and Devicesmentioning

confidence: 99%

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confidence: 99%

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Electronics and optoelectronics of two-dimensional transition metal dichalcogenides

et al. 2012

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“…Thus, in addition to high velocity, a high density of states (DOS) is equally attractive for attaining high speed. Driven by higher valley degeneracy, multilayer MoS 2 has the potential for considerably higher current drives than SL MoS 2 in the ultrascaled limit, and high charge densities have recently been reported 15 . Even in the long-channel structure, thin-film MoS 2 can take advantage of its multilayer nature.…”

Section: Resultsmentioning

confidence: 99%

High-mobility and low-power thin-film transistors based on multilayer MoS2 crystals

et al. 2012

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unlike graphene, the existence of bandgaps (1-2 eV) in the layered semiconductor molybdenum disulphide, combined with mobility enhancement by dielectric engineering, offers an attractive possibility of using single-layer molybdenum disulphide field-effect transistors in low-power switching devices. However, the complicated process of fabricating single-layer molybdenum disulphide with an additional high-k dielectric layer may significantly limit its compatibility with commercial fabrication. Here we show the first comprehensive investigation of processfriendly multilayer molybdenum disulphide field-effect transistors to demonstrate a compelling case for their applications in thin-film transistors. our multilayer molybdenum disulphide field-effect transistors exhibited high mobilities ( > 100 cm 2 V − 1 s − 1 ), near-ideal subthreshold swings (~70 mV per decade) and robust current saturation over a large voltage window. With simulations based on shockley's long-channel transistor model and calculations of scattering mechanisms, these results provide potentially important implications in the fabrication of highresolution large-area displays and further scientific investigation of various physical properties expected in other layered semiconductors.

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“…35,43,44 Figure 3b The drastically different behavior observed in devices with 2D/2D hetero-contacts can be attributed to the differences in band alignments between the channel and contact materials. 45 In the MoSe 2 directly underneath the drain/source contacts ( region I in Fig.…”

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confidence: 99%

Low-Resistance 2D/2D Ohmic Contacts: A Universal Approach to High-Performance WSe₂, MoS₂, and MoSe₂ Transistors

et al. 2016

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We report a new strategy for fabricating 2D/2D low-resistance ohmic contacts for a variety of transition metal dichalcogenides (TMDs) using van der Waals assembly of substitutionally doped TMDs as drain/source contacts and TMDs with no intentional doping as channel materials. We demonstrate that few-layer WSe 2 field-effect transistors (FETs) with 2D/2D contacts exhibit low contact resistances of ~ 0.3 kΩ µm, high on/off ratios up to > 10 9 , and high drive currents exceeding 320 µA µm -1 . These favorable characteristics are combined with a two-terminal field-effect hole mobility μ FE ≈ 2×10 2 cm 2 V -1 s -1 at room temperature, which increases to >2×10 3 cm 2 V -1 s -1 at cryogenic temperatures. We observe a similar performance also in MoS 2 and MoSe 2 FETs with 2D/2D drain and source contacts. The 2D/2D low-resistance ohmic contacts presented here represent a new device paradigm that overcomes a significant bottleneck in the performance of TMDs and a wide variety of other 2D materials as the channel materials in post-silicon electronics.

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Ambipolar MoS₂ Thin Flake Transistors

Cited by 782 publications

References 22 publications

Electronics and optoelectronics of two-dimensional transition metal dichalcogenides

Electronics and optoelectronics of two-dimensional transition metal dichalcogenides

High-mobility and low-power thin-film transistors based on multilayer MoS2 crystals

Low-Resistance 2D/2D Ohmic Contacts: A Universal Approach to High-Performance WSe₂, MoS₂, and MoSe₂ Transistors

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Ambipolar MoS2 Thin Flake Transistors

Cited by 782 publications

References 22 publications

Electronics and optoelectronics of two-dimensional transition metal dichalcogenides

Electronics and optoelectronics of two-dimensional transition metal dichalcogenides

High-mobility and low-power thin-film transistors based on multilayer MoS2 crystals

Low-Resistance 2D/2D Ohmic Contacts: A Universal Approach to High-Performance WSe2, MoS2, and MoSe2 Transistors

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Product

Resources

About

Ambipolar MoS₂ Thin Flake Transistors

Low-Resistance 2D/2D Ohmic Contacts: A Universal Approach to High-Performance WSe₂, MoS₂, and MoSe₂ Transistors