Edge structures and properties of triangular antidots in single-layer MoS2

Gan, Li; Cheng, Yingchun; Schwingenschlögl, Udo; Yao, Yingbang; Zhao, Yong; Zhang, Xixiang; Huang, Wei

doi:10.1063/1.4962132

Cited by 16 publications

(17 citation statements)

References 43 publications

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“…Interestingly, we found that these bright edge regions of the α domain are populated with a number of triangular holes with sizes of 25–2500 nm 2 (Figure b). We believe that these holes are a result of gradual oxidative etching by absorbed water and oxygen molecules . It is noteworthy that no such damage is found in the β domains.…”

Section: Discussionmentioning

confidence: 80%

Revealing the Atomic Defects of WS₂ Governing Its Distinct Optical Emissions

Lin

Komsa

et al. 2017

Adv Funct Materials

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Defects and their spatial distribution are crucial factors in controlling the electronic and optical properties of semiconductors. By using scanning transmission electron microscopy and electron energy loss spectroscopy, the type of impurities/defects in WS 2 subdomains with different optical properties is successfully assigned. A higher population of Cr impurities is found in the W-terminated edge domain, while the S-terminated domain contains more Fe impurities, in accordance with the luminescence characteristics of chemical-vapor-grown WS 2 of a hexagonal shape. In agreement with the firstprinciples calculations, the domains with Cr substitutional dopants exhibit strong trion emission. Fe atoms tend to gather into trimer configuration and introduce deep acceptor levels which compensate the n-type doping and suppress trion emission. It is also discovered that the domain with higher luminescence but smaller defect concentration tends to get oxidized more rapidly and degrade the 2D structure with many triangular holes. Excitons tend to accumulate at the edges of the oxidized triangular holes and results in enhanced PL emission. The findings indicate that choosing stable elements as dopant and controlling the number of specific edge structures within a crystal domain of 2D transitional metal dichalcogenides can be a new route to improve the optical properties of these materials.

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Section: Discussionmentioning

confidence: 80%

Revealing the Atomic Defects of WS₂ Governing Its Distinct Optical Emissions

Lin

Komsa

et al. 2017

Adv Funct Materials

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“…When heated in the presence of oxygen, the reaction forms MoO 3 and SO 2 molecules: MoS 2(s) + 3.5O 2(g) → MoO 3(s/g) + 2SO 2(g) (1) The temperature at which the reaction occurs is greatly determined by the condition of the material, reportedly ranging from 100°C for a powder 20 , to 400°C 22 for sputtered MoS 2 coatings. The oxidative thinning and/or etching of 2D MoS 2 can be achieved by heating in the presence of O 2 to ∼240°C or higher [1][2][3][4]23 . Other oxidants have also been used such as the more reactive O 3 24,25 , XeF 2 26 and oxygen containing plasmas [27][28][29] .…”

Section: Introductionmentioning

confidence: 99%

“…Other oxidants have also been used such as the more reactive O 3 24,25 , XeF 2 26 and oxygen containing plasmas [27][28][29] . Many reports demonstrate a mesh of quasiequilateral triangular pits in the MoS 2 surface after exposure to oxidizing conditions [1][2][3]23 . These pits are likely bounded by the p-doped zig-zag-Mo edge, with each Mo atom bonded to two O atoms in a wide range of O chemical potentials 2,23,30,31 .…”

Section: Introductionmentioning

confidence: 99%

“…Many reports demonstrate a mesh of quasiequilateral triangular pits in the MoS 2 surface after exposure to oxidizing conditions [1][2][3]23 . These pits are likely bounded by the p-doped zig-zag-Mo edge, with each Mo atom bonded to two O atoms in a wide range of O chemical potentials 2,23,30,31 . At temperatures above ∼250°C, the density of etched pits depends on the availability of defect sites about which to nucleate.…”

Section: Introductionmentioning

confidence: 99%

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Defect-moderated oxidative etching of MoS2

Maguire

Jadwiszczak

O’Brien

et al. 2019

Journal of Applied Physics

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We report a simple technique for the selective etching of bilayer and monolayer MoS 2 . In this work, chosen regions of MoS 2 were activated for oxygen adsorption and reaction by the application of low doses of He + at 30 keV in a gas ion microscope. Raman spectroscopy, optical microscopy and scanning electron microscopy were used to characterize both the etched features and the remaining material. It has been found that by using a pre-treatment to introduce defects, MoS 2 can be etched very efficiently and with high region specificity by heating in air.

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“…As the size of antidots is increased, creating a RTA lattice becomes slightly more energetically favorable than creating an ETA lattice, while the energy gaps in ETA structures are slightly larger than those in RTA structures. Interestingly, the linear reduction of formation energy by increasing the size of similar ETA lattices but passivated by oxygen atoms has also been reported in single-layer MoS 2 antidots using DFT calculations combined with experiments 38 . Moreover, it is suggested that since the formation energy of all antidot sizes and shapes is negative, it is probably feasible to create them by heating the samples in air 38 .…”

Section: Resultsmentioning

confidence: 57%

A DFT study on the electronic and magnetic properties of triangular graphene antidot lattices

2018

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We explore the effect of antidot size on electronic and magnetic properties of graphene antidot lattices from first-principles calculations. The spin-polarized density of states, band gap, formation energy and the total magnetization of two different equilateral triangular and right triangular antidots with zigzag and mixed zigzagarmchair edges are studied. We find that although the values of band gap, formation energy and the total magnetization of both structures are different, these values may increase when the number of zigzag edges is increased. The armchair edges have no contribution in the total magnetization of right triangular antidots. The induced magnetic moments are mainly localized on the edge atoms with a maximum value at the center of each side of the triangles. We show that a spin-dependent band gap opens up in bilayer graphene as a result of antidot pattern in only one layer of the structure. Such periodic arrays of triangular antidots that cause a spin-dependent band gap around the Fermi energy can be utilized for turning graphene from a diamagnetic semimetal into a magnetic semiconductor. arXiv:1812.06249v1 [cond-mat.mes-hall]

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Edge structures and properties of triangular antidots in single-layer MoS2

Cited by 16 publications

References 43 publications

Revealing the Atomic Defects of WS₂ Governing Its Distinct Optical Emissions

Revealing the Atomic Defects of WS₂ Governing Its Distinct Optical Emissions

Defect-moderated oxidative etching of MoS2

A DFT study on the electronic and magnetic properties of triangular graphene antidot lattices

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Edge structures and properties of triangular antidots in single-layer MoS2

Cited by 16 publications

References 43 publications

Revealing the Atomic Defects of WS2 Governing Its Distinct Optical Emissions

Revealing the Atomic Defects of WS2 Governing Its Distinct Optical Emissions

Defect-moderated oxidative etching of MoS2

A DFT study on the electronic and magnetic properties of triangular graphene antidot lattices

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Product

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Revealing the Atomic Defects of WS₂ Governing Its Distinct Optical Emissions

Revealing the Atomic Defects of WS₂ Governing Its Distinct Optical Emissions