Flatlands in the Holy Land: The Evolution of Layered Materials Research in Israel

Hod, Oded; Urbakh, Michael; Naveh, Doron; Bar‐Sadan, Maya; Ismach, Ariel

doi:10.1002/adma.201706581

Cited by 7 publications

(5 citation statements)

References 121 publications

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“…This assumption may be sometimes quite far from reality, indeed the atomically smooth surfaces of 2D materials make interfacial sliding particularly easy, giving rise to the phenomenon of superlubrification (near‐zero friction) when a 2D material sits on atomically flat substrates, including itself (weak shear). [ 68 ] Note S7 in the Supporting Information provides the evidence, based on Raman results, that a strong‐shear coupling sets up both in spontaneus and engineered domes. In Figure 4d we show the values of Γ for each investigated dome.…”

Section: Resultsmentioning

confidence: 99%

Nanoscale Measurements of Elastic Properties and Hydrostatic Pressure in H₂‐Bulged MoS₂ Membranes

Giorgio

Blundo

Pettinari

et al. 2020

Adv Materials Inter

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defects, and intercalations, [14-18] charge carrier doping, [19-21] charge transfer, [22,23] and pressure. [24] In addition to this, due to its intrinsic atomically smooth surface, it has been regarded as an ideal barrier for tunneling junctions. [25] Single-layer MoS 2 has been theoretically predicted to withstand a critical intrinsic stress and strain of σ c ≈ 24GPa and ε c ≈ 20% for biaxial tensile deformations (and higher for uniaxial), by employing first-principle calculations and investigating the stress-strain (σ − ε) relations up to the failure point. [26,27] On the other hand, experimental estimates of ε c in MoS 2 sheets subjected to nanoindentation (which has the effect of a biaxial tensile stress), lead to lower values, ε c = 6%-13%, [27,28] for measured σ c close to the expected one. The discrepancy in the experimental value of ε c is caused by the use of a linear σ − ε relation, σ = Yε, where Y is the material Young's modulus, in a no-longer linear regime (close to the breaking point). Recently, the excellent robustness and flexibility of MoS 2 and other 2D crystals has led to a keen interest into 2D-material-blisters, such as bubbles, wrinkles, and tents. Their spontaneous formation has been observed after transferring 2D materials on top of a substrate, or on stacks of van der Waals (vdW) heterostructures, and it has been attributed to the trapping of adsorbed water and/or hydrocarbons inevitably present on the individual layers before assembly. [29-31] Moreover, The combination of extremely high stiffness and bending flexibility with tunable electrical and optical properties makes van der Waals transition metal dichalcogenides appealing both for fundamental science and applied research. By taking advantage of localized H 2-bulged MoS 2 membranes, an innovative approach, based on atomic force microscopy nanoindentation, is demostrated and discussed here, aiming at measuring elastic and thermodynamic properties of nanoblisters made of 2D materials. The results, interpreted in the membrane limit of the Föppl-von Karman equation, lead to the quantification of the internal pressure and mole number of the trapped H 2 gas, as well as of the stretching modulus and adhesion energy of the MoS 2 membrane. The latter is discussed in the limit of strong (clamped and fully bonded interlayer interface) shear, as experimentally achieved in the investigated H 2-bulged 2D blisters. Moreover, this approach allows to quantify the stress, and consequently the strain, locally imposed to the MoS 2 membrane by the bulging of the domes.

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Section: Resultsmentioning

confidence: 99%

Nanoscale Measurements of Elastic Properties and Hydrostatic Pressure in H₂‐Bulged MoS₂ Membranes

Giorgio

Blundo

Pettinari

et al. 2020

Adv Materials Inter

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“…For example, the interface in graphene bilayer and graphene–hBN heterostructure may rotate itself and cause strain in the 2D material lattice, driven by the vdW interaction . Overall, research about 2D material multilayers and heterostructures is still considered to be in its beginnings (as illustrated later) …”

Section: Mechanical Characterizations Of the 2d Material–substrate Inmentioning

confidence: 99%

Strain Engineering of 2D Materials: Issues and Opportunities at the Interface

2019

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applications of 2D materials emerging at large strain levels. [8][9][10] Considering difficulties associated with building a microelectromechanical system for straining freestanding 2D materials, [11] 2D materials were often transferred onto a substrate such that the strain can be introduced to the 2D material by controlling the deformation of the bulk substrate. [12] Such fact has led to significant advances in the strategies for straining 2D materials with a film-substrate system, as well as in interface metrologies for the van der Waals (vdW) interaction between the 2D material and its substrate.Here, we first summarize recent experimental achievements on realizing mechanical strain to substrate-supported 2D materials by categorizing the deformation modes of the 2D material-substrate system. These deformation modes include in-plane modes caused by epitaxy, thermal-expansion mismatch, and stretching/compressing the substrate, as well as out-of-plane modes caused by wrinkling and buckling of 2D materials, bulging and poking 2D materials, and transferring 2D materials on a patterned substrate. We then review recent experimental characterizations of the mechanical response of 2D material-substrate interfaces to in-plane shear deformations and out-of-plane delamination. This is not meant to be an all-encompassing analysis of the broad-field topic of strain engineering, but instead, we point out how mechanical deformations are achieved into 2D materials within the film/ substrate system and how the mechanics of interfaces govern these deformation mechanisms. The goal is to deterministically apply both strain magnitude and strain distribution into these atomically thin films and ultimately achieve strain-coupled fundamental physics and chemistry, and exciting applications in a controllable manner. Considering the interdisciplinary nature of research in this field, we also refer the readers to comprehensive reviews from relevant perspectives, including synthesis of emerging 2D materials, characterizations of the strain in 2D materials (especially via the Raman spectroscopy), and applications of mechanically strained 2D materials. [6,13,14] 2D Materials

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“…The pioneering work on the vapor-phase growth of single- and few-layer MoS 2 led to significant effort by the scientific community to realize methodologies for the large-area growth of 2D materials in general. As a result, extensive research has been carried to study chemical vapor deposition (CVD) growth of single- and few-layer atomic films in general and transition metal dichalcogenides (TMDCs) in particular. − CVD of TMDCs often relies on the evaporation of metal oxide solid powders as the source for the transition metals (Mo, W, etc. ) to be reacted with the chalcogen, usually obtained from a solid source as well.…”

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confidence: 99%

Growth-Etch Metal–Organic Chemical Vapor Deposition Approach of WS₂ Atomic Layers

et al. 2020

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Metal−organic chemical vapor deposition (MOCVD) is one of the main methodologies used for thin-film fabrication in the semiconductor industry today and is considered one of the most promising routes to achieve large-scale and high-quality 2D transition metal dichalcogenides (TMDCs). However, if special measures are not taken, MOCVD suffers from some serious drawbacks, such as small domain size and carbon contamination, resulting in poor optical and crystal quality, which may inhibit its implementation for the large-scale fabrication of atomic-thin semiconductors. Here we present a growthetch MOCVD (GE-MOCVD) methodology, in which a small amount of water vapor is introduced during the growth, while the precursors are delivered in pulses. The evolution of the growth as a function of the amount of water vapor, the number and type of cycles, and the gas composition is described. We show a significant domain size increase is achieved relative to our conventional process. The improved crystal quality of WS 2 (and WSe 2 ) domains wasis demonstrated by means of Raman spectroscopy, photoluminescence (PL) spectroscopy, and HRTEM studies. Moreover, time-resolved PL studies show very long exciton lifetimes, comparable to those observed in mechanically exfoliated flakes. Thus, the GE-MOCVD approach presented here may facilitate their integration into a wide range of applications.

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Flatlands in the Holy Land: The Evolution of Layered Materials Research in Israel

Cited by 7 publications

References 121 publications

Nanoscale Measurements of Elastic Properties and Hydrostatic Pressure in H₂‐Bulged MoS₂ Membranes

Nanoscale Measurements of Elastic Properties and Hydrostatic Pressure in H₂‐Bulged MoS₂ Membranes

Strain Engineering of 2D Materials: Issues and Opportunities at the Interface

Growth-Etch Metal–Organic Chemical Vapor Deposition Approach of WS₂ Atomic Layers

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Flatlands in the Holy Land: The Evolution of Layered Materials Research in Israel

Cited by 7 publications

References 121 publications

Nanoscale Measurements of Elastic Properties and Hydrostatic Pressure in H2‐Bulged MoS2 Membranes

Nanoscale Measurements of Elastic Properties and Hydrostatic Pressure in H2‐Bulged MoS2 Membranes

Strain Engineering of 2D Materials: Issues and Opportunities at the Interface

Growth-Etch Metal–Organic Chemical Vapor Deposition Approach of WS2 Atomic Layers

Contact Info

Product

Resources

About

Nanoscale Measurements of Elastic Properties and Hydrostatic Pressure in H₂‐Bulged MoS₂ Membranes

Nanoscale Measurements of Elastic Properties and Hydrostatic Pressure in H₂‐Bulged MoS₂ Membranes

Growth-Etch Metal–Organic Chemical Vapor Deposition Approach of WS₂ Atomic Layers