Graphene adhesion on MoS2 monolayer: An ab initio study

Ma, Yandong; Dai, Ying; Guo, Meng; Niu, Chengwang; Huang, Baibiao

doi:10.1039/c1nr10577a

Cited by 360 publications

(339 citation statements)

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“…Another arrangement, where a C atom sits above a S atom, has been shown to be energetically and electronically equivalent to that of the TM configuration. 34,35 Once the graphene/MoS 2 supercell is constructed, oxygen functional groups are randomly attached above and below the graphene plane. 38,39 GO structures are obtained by relaxing the supercell without the MoS 2 monolayer first, and then the MoS 2 monolayer is introduced with an initial distance between the C plane of GO and the Mo plane of MoS 2 of 4.85 Å, which is the van der Waals distance obtained for the MoS 2 /graphene case.…”

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confidence: 99%

Graphene Oxide as a Promising Hole Injection Layer for MoS₂-Based Electronic Devices

et al. 2014

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M any two-dimensional (2D) materials exist in bulk form as stacks of bonded layers with weak van der Waals interlayer attraction. Thanks to their particular structure, they can be exfoliated into atomically thin monolayers that hold promise for next-generation flexible electronics and optoelectronics. 1,2 Graphene has received much attention in the past decade, 3 due in large part to exceptional electronic properties such as its ultrahigh carrier mobility. However, the absence of a band gap has limited the progress of graphene-based technologies. For example, graphene field-effect transistors (FETs) cannot be turned off effectively, and even though small band gaps have been successfully opened in graphene, 4À7 the development of devices operating at room temperature with a low stand-by power dissipation remains a challenge. 8 On the other hand, transition-metal dichalcogenides (TMDCs) are a class of directband gap semiconductors that are emerging as strong candidates in next-generation nanoelectronic devices. 8À12 In the monolayer form, their lack of dangling bonds, structural stability, and mobility values comparable to Si make them optimal as channel materials in FETs. 1 In particular, FETs based on single layer MoS 2 , which has a direct band gap of 1.8 eV 1,13 and mobility in the range 1À50 cm 2 V À1 s À1 at room temperature, 14À17 show low power dissipation, 8 efficient control over switching 9 and reduction of shortchannel effects. 18,19 However, in order to develop logic circuits based on TMDCs, it is necessary to fabricate both n-and p-type FETs. TMDC FETs based on a Schottky device architecture can transport either electrons (n-FET) or holes (p-FET) in the conducting channel, depending on whether the Schottky barrier height (SBH) is smaller relative to the conduction or the valence band, respectively. 20 While monolayer n-FETs have been widely reported, fabrication of p-FETs has been challenging. 20 This is due to the relative difficulty in designing MoS 2 /metal contacts * Address correspondence to tiziana.musso@aalto.fi. Our analysis shows that this is possible due to the high work function of GO and the relatively weak Fermi-level pinning at the MoS 2 /GO interfaces compared to traditional MoS 2 /metal systems (common metals are Ag, Al, Au, Ir, Pd, Pt). The combination of easy-to-fabricate and inexpensive GO with MoS 2 could be promising for the development of hybrid all-2D p-type electronic and optoelectronic devices on flexible substrates.

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Graphene Oxide as a Promising Hole Injection Layer for MoS₂-Based Electronic Devices

et al. 2014

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“…Up to now, significant experimental and theoretical efforts have been made to characterize and explore new structures, properties and applications of 2D van der Waals heterojunctions, especially graphene based heterojunctions, such as graphene/hexagonal boron nitride (G/h-BN) [54][55][56][57][58], graphene/silicene (G/S) [59][60][61], graphene/phosphorene (G/P) [62][63][64], graphene/graphitic carbon nitride (G/g-C 3 N 4 ) [65][66][67], graphene/graphitic zinc oxide (G/g-ZnO) [68][69][70], graphene/molybdenum disulphide (G/MoS 2 ) [71][72][73][74][75], graphene/molybdenum disulfide (G/MoSe 2 ) [76][77][78], silicene/hexagonal boron nitride (S/h-BN) [79][80][81], silicene/molybdenum disulphide (S/MoS 2 ) [82][83][84], and TMDCs based heterojunctions [85][86][87]. These van der Waals heterojunctions show much more new properties far beyond their single components.…”

Section: Introductionmentioning

confidence: 99%

First-principles study of two-dimensional van der Waals heterojunctions

Yang

2016

Computational Materials Science

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Research on graphene and other two-dimensional (2D) materials, such as silicene, germanene, phosphorene, hexagonal boron nitride (h-BN), graphitic carbon nitride (g-C3N4), graphitic zinc oxide (g-ZnO) and molybdenum disulphide (MoS2), has recently received considerable interest owing to their outstanding optoelectronic properties and wide applications. Looking beyond this field, combining the electronic structures of 2D materials in ultrathin van der Waals heterojunctions has also emerged to widely study theoretically and experimentally to explore some new properties and potential applications beyond their single components. Here, this article reviews our recent theoretical studies on the structural, electronic, electrical and optical properties of 2D van der Waals heterojunctions using density functional theory calculations, including the Graphene/Silicene, Graphene/Phosphorene, Graphene/g-ZnO, Graphene/MoS2 and g-C3N4/MoS2 heterojunctions. Our theoretical simulations, designs and calculations show that novel 2D van der Waals heterojunctions provide a promising future for electronic, electrochemical, photovoltaic, photoresponsive and memory devices in the experiments.

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“…[11] and indicates a weak interlayer bonding of van der Waals-type. Based on this setup, we simulated realistic edge and impurity effects on the electronic properties of graphene-MoS 2 hybrids.…”

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confidence: 99%

“…In Ref. [11] it is stated that another configuration, where C sits below an S atom, is equivalent in both the binding and electronic properties. (lower panel) Band structure of the system.…”

mentioning

confidence: 99%

Doping mechanisms in graphene-MoS2 hybrids

Sachs¹,

Britnell²,

Wehling³

et al. 2013

Applied Physics Letters

116

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We present a joint theoretical and experimental investigation of charge doping and electronic potential landscapes in hybrid structures composed of graphene and semiconducting single layer MoS2. From first-principles simulations we find electron doping of graphene due to the presence of rhenium impurities in MoS2. Furthermore, we show that MoS2 edges give rise to charge reordering and a potential shift in graphene, which can be controlled through external gate voltages. The interplay of edge and impurity effects allows the use of the graphene-MoS2 hybrid as a photodetector. Spatially resolved photocurrent signals can be used to resolve potential gradients and local doping levels in the sample.Being a truly two-dimensional material [1], graphene can be integrated into hybrid structures with other 2D crystals such as boron nitride (BN), tungsten disulfide (WS 2 ) or molybdenum disulfide (MoS 2 ) [2-6]. The ability to build 'on demand' complex heterostructures via layer-by-layer integration establishes a whole family of new materials with widely varying characteristics and exciting possibilities for novel 2D nanodevices [7][8][9]. A prerequisite for future electronic applications lies in the understanding of interface effects when different building blocks come together. In particular, the electronic properties of realistic interfaces of graphene and two-dimensional materials present an open problem.In this work, we investigate heterostructures made of graphene and the semiconducting transition metal dichalcogenide MoS 2 , a system that has already been utilized for vertical field-effect transistors [3]. We study how different charge transfer mechanisms control relative Fermi level positions, built-in electric fields and charge reordering at realistic graphene-MoS2 interfaces. The simulated charge and potential landscapes are compared to photovoltaic measurements.In order to investigate the graphene-MoS 2 hybrid structures theoretically, we performed first-principles density functional theory (DFT) simulations [10]. As the lattice constant of isolated graphene is about 23% smaller than the one of isolated MoS 2 , we constructed a supercell consisting of a 5x5 layer graphene (50 C atoms) coated with a 4x4 layer MoS 2 (16 Mo atoms and 32 S atoms) with a stacking as shown in Fig. 1b to account for this lattice mismatch. The remaining lattice mismatch of about 3-4% is reasonably small and compensated by a slight strain of graphene to the MoS 2 lattice constant.The graphene-MoS 2 structure was then fully relaxed, which leads to an equilibrium graphene-MoS 2 distance of 3.35 A in good agreement with Ref.[11] and indicates a weak interlayer bonding of van der Waals-type. Based on this setup, we simulated realistic edge and impurity effects on the electronic properties of graphene-MoS 2 hybrids.We first address the role of impurity effects. To this end, we consider the fully MoS 2 -covered graphene as in Fig. 1b without impurities and compare it to the case with impurities in the MoS 2 . The band diagram of the pristine sy...

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Graphene adhesion on MoS2 monolayer: An ab initio study

Cited by 360 publications

References 38 publications

Graphene Oxide as a Promising Hole Injection Layer for MoS₂-Based Electronic Devices

Graphene Oxide as a Promising Hole Injection Layer for MoS₂-Based Electronic Devices

First-principles study of two-dimensional van der Waals heterojunctions

Doping mechanisms in graphene-MoS2 hybrids

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Graphene adhesion on MoS2 monolayer: An ab initio study

Cited by 360 publications

References 38 publications

Graphene Oxide as a Promising Hole Injection Layer for MoS2-Based Electronic Devices

Graphene Oxide as a Promising Hole Injection Layer for MoS2-Based Electronic Devices

First-principles study of two-dimensional van der Waals heterojunctions

Doping mechanisms in graphene-MoS2 hybrids

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Graphene Oxide as a Promising Hole Injection Layer for MoS₂-Based Electronic Devices

Graphene Oxide as a Promising Hole Injection Layer for MoS₂-Based Electronic Devices