Layer-engineered atomic-scale spalling of 2D van der Waals crystals

Moon, Ji‐Yun; Kim, Do-Hoon; Kim, Seung‐Il; Hwang, Hyun-Sik; Choi, Jun-Hui; Hyeong, Seok‐Ki; Ghods, Soheil; Park, Hyeongsik; Kim, Eui‐Tae; Bae, Sukang; Lee, Seoung‐Ki; Son, Seok‐Kyun; Lee, Jae-Hyun

doi:10.1016/j.matt.2022.07.021

Cited by 12 publications

(4 citation statements)

References 43 publications

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“…To further examine the exfoliation of thicker flakes, we employ an analytical model previously applied to explain thickness-selective spalling in both 2D and 3D semiconductors. ,, In this model, strain accumulates in the bulk crystal as a result of the tensile metal thin film (Figure S14). At a given depth (the spalling depth), the accumulated strain energy in the thin film and bulk crystal equals the crystal’s internal binding energy.…”

Section: Resultsmentioning

confidence: 99%

“…One hundred nanometer of the desired metal was evaporated on the surface of a freshly cleaved bulk hBN crystal (2D semiconductor) at a rate of 0.5 Å/s using an e-beam evaporator (LAB18 Kurt J. Lesker). The gold films used in this work are 20–30 nm thicker than those previously reported for hBN and graphene exfoliations. ,, The use of a thicker film helps prevent cracking or fracturing of the hBN flakes during exfoliation, which enables the exfoliation of millimeter-scale flakes. A 10 wt % solution of PVP (M.W.…”

Section: Methodsmentioning

confidence: 95%

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Millimeter-Scale Exfoliation of hBN with Tunable Flake Thickness for Scalable Encapsulation

McKeown-Green,

Zeng,

Saunders

et al. 2024

ACS Appl. Nano Mater.

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As a 2D dielectric material, hexagonal boron nitride (hBN) is in high demand for applications in photonic, nonlinear optic, and nanoelectronic devices as an atomically flat and thin dielectric or encapsulation layer. Unfortunately, the highthroughput preparation of macroscopic-scale hBN flakes with selective thickness is an ongoing challenge, limiting device fabrication and technological integration. Here, we use various metal thin films to prepare hBN flakes with millimeter-scale dimension, near-unity yields, and tunable flake thickness distributions from 1 to 7 layers. The single crystallinity and quality of the exfoliated hBN flakes are demonstrated with atomic force microscopy, Raman spectroscopy, and second-harmonic generation. We further explore a possible mechanism for flake-thickness selectivity based on thin-film residual stress measurements and density functional theory calculations. We demonstrate that our exfoliated, large-area hBN flakes can be incorporated as encapsulating layers for MoSe 2 monolayers to effectively protect against photodegradation. This method brings us one step closer to the high-throughput, mass production of hBN-based 2D photonic, optoelectronic, and quantum devices in the future.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 95%

Millimeter-Scale Exfoliation of hBN with Tunable Flake Thickness for Scalable Encapsulation

McKeown-Green,

Zeng,

Saunders

et al. 2024

ACS Appl. Nano Mater.

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“…Check the following reference for details on this. 1 , 9 We modulated the internal stress of the Ag stressor through continuous deposition and deposition with stress release time. The protocol below describes the specific steps for continuous deposition of Ag stressor.…”

Section: Step-by-step Methods Detailsmentioning

confidence: 99%

Protocol for preparing layer-engineered van der Waals materials through atomic spalling

Moon¹,

Kim²,

Josline³

et al. 2023

STAR Protocols

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“…Recent works about MoS 2 /graphene phototransistors exhibit promising performance but most of the results published on MoS 2 /graphene phototransistors are based on mechanically exfoliated 2D materials [1,18,[21][22][23] and electron-beam lithography to demonstrate the feasibility of a single device. However, a key drawback of these methods is that they are not scalable.…”

Section: Introductionmentioning

confidence: 99%

Towards large scale integration of MoS₂/graphene heterostructure with ALD-grown MoS₂

Hyot,

Ligaud,

Yoo

et al. 2024

Nanotechnology

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In the pursuit of ultrathin and highly sensitive photodetectors, a promising approach involves leveraging the combination of light-sensitive two-dimensional (2D) semiconducting transition-metal dichalcogenides (TMD), such as MoS2 and the high electrical conductivity of graphene. Over the past decade, exfoliated 2D materials and electron-beam lithography have been used extensively to demonstrate feasibility on single devices. But for these devices to be used in the real-world systems, it is necessary to demonstrate good device performance similar to lab-based devices with repeatability of the results from device to device and a path to large scale manufacturing. To work in this way, a fabrication process of MoS2/graphene vertical heterostructures with a wafer-scale integration in a CMOS compatible foundry environment is evaluated here. Large-scale Atomic Layer Deposition (ALD) on 8-inch silicon wafers is used for the growth of MoS2 layers which are then transferred on a 4-inch graphene-based wafer. The MoS2/graphene phototransistors are fabricated collectively, achieving a minimum channel length of 10 µm. The results measured on dozen of devices demonstrate a photoresponsivity of 50 A/W and a remarkable sensitivity as low as 10 nW at 660 nm. These results not only compete with lab-based photodetectors made of chemical vapor deposition (CVD) grown MoS2 layers transferred on graphene, but also pave the way for the large-scale integration of these emerging 2D heterostructures in optoelectronic devices and sensors.

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Layer-engineered atomic-scale spalling of 2D van der Waals crystals

Cited by 12 publications

References 43 publications

Millimeter-Scale Exfoliation of hBN with Tunable Flake Thickness for Scalable Encapsulation

Millimeter-Scale Exfoliation of hBN with Tunable Flake Thickness for Scalable Encapsulation

Protocol for preparing layer-engineered van der Waals materials through atomic spalling

Towards large scale integration of MoS₂/graphene heterostructure with ALD-grown MoS₂

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Layer-engineered atomic-scale spalling of 2D van der Waals crystals

Cited by 12 publications

References 43 publications

Millimeter-Scale Exfoliation of hBN with Tunable Flake Thickness for Scalable Encapsulation

Millimeter-Scale Exfoliation of hBN with Tunable Flake Thickness for Scalable Encapsulation

Protocol for preparing layer-engineered van der Waals materials through atomic spalling

Towards large scale integration of MoS2/graphene heterostructure with ALD-grown MoS2

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Towards large scale integration of MoS₂/graphene heterostructure with ALD-grown MoS₂