A reliable way of mechanical exfoliation of large scale two dimensional materials with high quality

Yuan, Lin; Ge, Juan; Peng, Xianglin; Zhang, Qian; Wu, Zefei; Yu, Jianying; Xiong, Xiaolu; Yin, Hairong; Han, Junfeng

doi:10.1063/1.4967967

Cited by 69 publications

(36 citation statements)

References 30 publications

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“…Developing their ternary, quaternary, or higher order mixtures having different metal/chalcogen dopants to engineer their physical properties is an active area of research . Top–down growth methods, such as liquid exfoliation, mechanical exfoliation, etc., are not viable for the morphology‐controlled 2D material synthesis because most of these engineered structures only form under nonequilibrium growth conditions. The chemical vapor deposition (CVD) technique is ideal for such morphology‐controlled structures because the growth process in this case can be tuned both kinetically and thermodynamically by controlling the pressure temperature profile …”

Section: Comparison Of Tafel Slopes Of Triangles and Dendritesmentioning

confidence: 99%

On the Synthesis of Morphology‐Controlled Transition Metal Dichalcogenides via Chemical Vapor Deposition for Electrochemical Hydrogen Generation

Sharma

Sahoo

Rastogi

et al. 2019

Physica Rapid Research Ltrs

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Shape‐engineered atomically thin transition metal dichalcogenide (TMD) crystals are highly intriguing systems with regard to both fundamental and applied science. Herein, a chemical vapor deposition‐assisted generalized synthesis strategy for the triangular‐ and dendritic‐shaped TMDs and their ternary alloys is proposed, and the TMD structures' potential for electrocatalytic hydrogen evolution reaction (HER) applications is demonstrated. The alloy formation is confirmed via micro‐Raman and photoluminescence studies and further verified using transmission electron microscopy and X‐ray photoelectron spectroscopy. The HER activities of MoS2 and MoSe2 triangles are compared with those of their dendritic structures, and an enormous improvement in terms of overpotential and current density is observed for the dendritic structures. A further enhancement of the HER activity is observed in MoS2(1−x)Se2x triangular and dendritic structures, with dendritic MoS2(1−x)Se2x providing the best activity. The demonstrated nonequilibrium growth technique opens new avenues for the synthesis of morphology‐controlled, large area, complex, and atomically thin TMD structures, which can have unprecedented properties, such as the enormous catalytic activity, tunable luminescence, etc., as presented in this article.

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Section: Comparison Of Tafel Slopes Of Triangles and Dendritesmentioning

confidence: 99%

On the Synthesis of Morphology‐Controlled Transition Metal Dichalcogenides via Chemical Vapor Deposition for Electrochemical Hydrogen Generation

Sharma

Sahoo

Rastogi

et al. 2019

Physica Rapid Research Ltrs

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show abstract

“…3c, the PL intensity of stacked bilayer MoS 2 with rGO (M/rGO/M) region is twice that of rGO on monolayer MoS 2 (rGO/M) or monolayer MoS 2 on rGO (M/rGO) regions. In previous reports, PL quenching was observed in MoS 2 over mechanically exfoliated graphene (MEG) because MEG has semi-metallic properties that result in a metal-semiconductor interface 27,28 . On the other hand, rGO show semiconductor behavior because of residual oxygen functional groups after thermal annealing 29,30 .…”

Section: Resultsmentioning

confidence: 99%

Fabrication of Stacked MoS2 Bilayer with Weak Interlayer Coupling by Reduced Graphene Oxide Spacer

Kim

et al. 2019

Sci Rep

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We fabricated the stacked bilayer molybdenum disulfide (MoS 2 ) by using reduced graphene oxide (rGO) as a spacer for increasing the optoelectronic properties of MoS 2 . The rGO can decrease the interlayer coupling between the stacked bilayer MoS 2 and retain the direct band gap property of MoS 2 . We observed a twofold enhancement of the photoluminescence intensity of the stacked MoS 2 bilayer. In the Raman scattering, we observed that the E 1 2g and A 1g modes of the stacked bilayer MoS 2 with rGO were further shifted compared to monolayer MoS 2 , which is due to the van der Waals (vdW) interaction and the strain effect between the MoS 2 and rGO layers. The findings of this study will expand the applicability of monolayer MoS 2 for high-performance optoelectronic devices by enhancing the optical properties using a vdW spacer.

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“…Challenges lie in reliable synthesis of atomically thick 2D layers and controlled manipulation of electronic properties [ 13 ]. Though mechanical cleaving still remains a relatively facile technique to prepare high quality single to few layered WS 2 , problems such as absence of control over thickness, relatively small lateral size and low yield limit its applications and commercialization [ 14 , 15 ]. The most popular techniques to produce few-layered WS 2 include intercalation driven exfoliation [ 16 ], liquid phase exfoliation [ 17 ], physical vapor deposition [ 18 ], hydrothermal reaction [ 19 ], and heat treatment of W and S containing precursors [ 20 ].…”

Section: Introductionmentioning

confidence: 99%

Interface Kinetics Assisted Barrier Removal in Large Area 2D-WS2 Growth to Facilitate Mass Scale Device Production

et al. 2021

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Growth of monolayer WS2 of domain size beyond few microns is a challenge even today; and it is still restricted to traditional exfoliation techniques, with no control over the dimension. Here, we present the synthesis of mono- to few layer WS2 film of centimeter2 size on graphene-oxide (GO) coated Si/SiO2 substrate using the chemical vapor deposition CVD technique. Although the individual size of WS2 crystallites is found smaller, the joining of grain boundaries due to sp2-bonded carbon nanostructures (~3–6 nm) in GO to reduced graphene-oxide (RGO) transformed film, facilitates the expansion of domain size in continuous fashion resulting in full coverage of the substrate. Another factor, equally important for expanding the domain boundary, is surface roughness of RGO film. This is confirmed by conducting WS2 growth on Si wafer marked with few scratches on polished surface. Interestingly, WS2 growth was observed in and around the rough surface irrespective of whether polished or unpolished. More the roughness is, better the yield in crystalline WS2 flakes. Raman mapping ascertains the uniform mono-to-few layer growth over the entire substrate, and it is reaffirmed by photoluminescence, AFM and HRTEM. This study may open up a new approach for growth of large area WS2 film for device application. We have also demonstrated the potential of the developed film for photodetector application, where the cycling response of the detector is highly repetitive with negligible drift.

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A reliable way of mechanical exfoliation of large scale two dimensional materials with high quality

Cited by 69 publications

References 30 publications

On the Synthesis of Morphology‐Controlled Transition Metal Dichalcogenides via Chemical Vapor Deposition for Electrochemical Hydrogen Generation

On the Synthesis of Morphology‐Controlled Transition Metal Dichalcogenides via Chemical Vapor Deposition for Electrochemical Hydrogen Generation

Fabrication of Stacked MoS2 Bilayer with Weak Interlayer Coupling by Reduced Graphene Oxide Spacer

Interface Kinetics Assisted Barrier Removal in Large Area 2D-WS2 Growth to Facilitate Mass Scale Device Production

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