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Li S, Lin J, Chen Y, Luo Z, Cheng H, Liu F, Zhang J, Wang S. Growth Anisotropy and Morphology Evolution of Line Defects in Monolayer MoS 2 : Atomic-Level Observation, Large-Scale Statistics, and Mechanism Understanding. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2303511. [PMID: 37749964 DOI: 10.1002/smll.202303511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 08/25/2023] [Indexed: 09/27/2023]
Abstract
Understanding the growth behavior and morphology evolution of defects in 2D transition metal dichalcogenides is significant for the performance tuning of nanoelectronic devices. Here, the low-voltage aberration-corrected transmission electron microscopy with an in situ heating holder and a fast frame rate camera to investigate the sulfur vacancy lines in monolayer MoS2 is applied. Vacancy concentration-dependent growth anisotropy is discovered, displaying first lengthening and then broadening of line defects as the vacancy densifies. With the temperature increase from 20 °C to 800 °C, the defect morphology evolves from a dense triangular network to an ultralong linear structure due to the temperature-sensitive vacancy migration process. Atomistic dynamics of line defect reconstruction on the millisecond time scale are also captured. Density functional theory calculations, Monte Carlo simulation, and configurational force analysis are implemented to understand the growth and reconstruction mechanisms at relevant time and length scales. Throughout the work, high-resolution imaging is closely combined with quantitative analysis of images involving thousands of atoms so that the atomic-level structure and the large-area statistical rules are obtained simultaneously. The work provides new ideas for balancing the accuracy and universality of discoveries in the TEM study and will be helpful to the controlled sculpture of nanomaterials.
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Affiliation(s)
- Shouheng Li
- Science and Technology on Advanced Ceramic Fibers and Composites Laboratory, College of Aerospace Science and Engineering, National University of Defense Technology, Changsha, 410073, P. R. China
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, P. R. China
| | - Jinguo Lin
- State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- School of Engineering Sciences, University of Chinese Academy of Sciences, Beijing, 100049, P.R. China
| | - Yun Chen
- Science and Technology on Advanced Ceramic Fibers and Composites Laboratory, College of Aerospace Science and Engineering, National University of Defense Technology, Changsha, 410073, P. R. China
| | - Zheng Luo
- Science and Technology on Advanced Ceramic Fibers and Composites Laboratory, College of Aerospace Science and Engineering, National University of Defense Technology, Changsha, 410073, P. R. China
| | - Haifeng Cheng
- Science and Technology on Advanced Ceramic Fibers and Composites Laboratory, College of Aerospace Science and Engineering, National University of Defense Technology, Changsha, 410073, P. R. China
| | - Feng Liu
- State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- School of Engineering Sciences, University of Chinese Academy of Sciences, Beijing, 100049, P.R. China
| | - Jin Zhang
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, P. R. China
- School of Advanced Materials, Peking University Shenzhen Graduate School, Shenzhen, 518055, P. R. China
| | - Shanshan Wang
- Science and Technology on Advanced Ceramic Fibers and Composites Laboratory, College of Aerospace Science and Engineering, National University of Defense Technology, Changsha, 410073, P. R. China
- School of Advanced Materials, Peking University Shenzhen Graduate School, Shenzhen, 518055, P. R. China
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2
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Zaw Win M, Hye Park J, Htet Naing H, Woo Hong M, Oo W, Bok Yi K. Analysis of Preservative Ability of Chitosan on CO Adsorption of CuCl-Alumina-Based Composites. J IND ENG CHEM 2023. [DOI: 10.1016/j.jiec.2022.12.051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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3
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Zhang H, Yu Y, Dai X, Yu J, Xu H, Wang S, Ding F, Zhang J. Probing Atomic-Scale Fracture of Grain Boundaries in Low-symmetry 2D Materials. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2102739. [PMID: 34643318 DOI: 10.1002/smll.202102739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 08/24/2021] [Indexed: 06/13/2023]
Abstract
Grain boundaries (GBs) play a central role in the fracture of polycrystals. However, the complexity of GBs and the difficulty in monitoring the atomic structure evolution during fracture greatly limit the understanding of the GB mechanics. Here, in situ aberration-corrected scanning transmission electron microscopy and density functional theory calculations are combined to investigate the fracture mechanics in low-symmetry, polycrystalline, 2D rhenium disulfide (ReS2 ), unveiling the distinctive crack behaviors at different GBs with atomic resolution. Brittle intergranular fracture prefers to rip through the GBs that are parallel to the Re chains of at least one side of the GBs. In contrast, those GBs, which do not align with Re chains on either side of the GBs, are highly resistant to fracture, impeding or deflecting the crack propagation. These results disclose the GB type-dependent mechanical failure of anisotropic 2D polycrystals, providing new ideas for material reinforcement and controllable cutting via GB engineering.
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Affiliation(s)
- Hui Zhang
- Science and Technology on Advanced Ceramic Fibers and Composites Laboratory, College of Aerospace Science and Engineering, National University of Defense Technology, Changsha, 410000, P. R. China
| | - Yue Yu
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, P. R. China
| | - Xinyue Dai
- Centre for Multidimensional Carbon Materials, Institute for Basic Science, Ulsan, 44919, South Korea
- School of Life Sciences, Shanghai University, Shanghai, 200444, P. R. China
| | - Jinshan Yu
- Science and Technology on Advanced Ceramic Fibers and Composites Laboratory, College of Aerospace Science and Engineering, National University of Defense Technology, Changsha, 410000, P. R. China
| | - Hua Xu
- Key Laboratory of Applied Surface and Colloid Chemistry Ministry of Education, Shaanxi Key Laboratory for Advanced Energy Devices, Shaanxi Engineering Lab for Advanced Energy Technology, School of Materials Science and Engineering, Shaanxi Normal University, Xi'an, 710119, P. R. China
| | - Shanshan Wang
- Science and Technology on Advanced Ceramic Fibers and Composites Laboratory, College of Aerospace Science and Engineering, National University of Defense Technology, Changsha, 410000, P. R. China
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, P. R. China
| | - Feng Ding
- Centre for Multidimensional Carbon Materials, Institute for Basic Science, Ulsan, 44919, South Korea
- School of Materials Science and Engineering, Ulsan, National Institute of Science and Technology, Ulsan, 44919, South Korea
| | - Jin Zhang
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, P. R. China
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4
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Xiao P, Mencarelli D, Chavez-Angel E, Joseph CH, Cataldo A, Pierantoni L, Sotomayor Torres CM, Sledzinska M. Reversing the Humidity Response of MoS 2- and WS 2-Based Sensors Using Transition-Metal Salts. ACS APPLIED MATERIALS & INTERFACES 2021; 13:23201-23209. [PMID: 33950679 DOI: 10.1021/acsami.1c03691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Two-dimensional materials, such as transition-metal dichalcogenides (TMDs), are attractive candidates for sensing applications due to their high surface-to-volume ratio, chemically active edges, and good electrical properties. However, their electrical response to humidity is still under debate and experimental reports remain inconclusive. For instance, in different studies, the impedance of MoS2-based sensors has been found to either decrease or increase with increasing humidity, compromising the use of MoS2 for humidity sensing. In this work, we focus on understanding the interaction between water and TMDs. We fabricated and studied humidity sensors based on MoS2 and WS2 coated with copper chloride and silver nitrate. The devices exhibited high chemical stability and excellent humidity sensing performance in relative humidity between 4 and 80%, with response and recovery times of 2 and 40 s, respectively. We have systematically investigated the humidity response of the materials as a function of the type and amount of induced metal salt and observed the reverse action of sensing mechanisms. This phenomenon is explained based on a detailed structural analysis of the samples considering the Grotthuss mechanism in the presence of charge trapping, which was represented by an appropriate lumped-element model. Our findings open up a possibility to tune the electrical response in a facile manner and without compromising the high performance of the sensor. They offer an insight into the time-dependent performance and aging of the TMD-based sensing devices.
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Affiliation(s)
- Peng Xiao
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain
- Departamento de Física, Universidad Autónoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
| | - Davide Mencarelli
- Department of Information Engineering, Polytechnic University of Marche, Via Brecce Bianche, 1, 60131 Ancona, Italy
- INFN-Laboratori Nazionali di Frascati, via E. Fermi 40, 00044 Frascati, Italy
| | - Emigdio Chavez-Angel
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Christopher Hardly Joseph
- Department of Information Engineering, Polytechnic University of Marche, Via Brecce Bianche, 1, 60131 Ancona, Italy
| | - Antonino Cataldo
- Department of Information Engineering, Polytechnic University of Marche, Via Brecce Bianche, 1, 60131 Ancona, Italy
- INFN-Laboratori Nazionali di Frascati, via E. Fermi 40, 00044 Frascati, Italy
| | - Luca Pierantoni
- Department of Information Engineering, Polytechnic University of Marche, Via Brecce Bianche, 1, 60131 Ancona, Italy
- INFN-Laboratori Nazionali di Frascati, via E. Fermi 40, 00044 Frascati, Italy
| | - Clivia M Sotomayor Torres
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain
- ICREA, Pg. Lluís Companys 23, 08010 Barcelona, Spain
| | - Marianna Sledzinska
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain
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5
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Fan Y, Li L, Yu G, Geng D, Zhang X, Hu W. Recent Advances in Growth of Large-Sized 2D Single Crystals on Cu Substrates. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2003956. [PMID: 33191567 DOI: 10.1002/adma.202003956] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 07/13/2020] [Indexed: 06/11/2023]
Abstract
Large-scale and high-quality 2D materials have been an emerging and promising choice for use in modern chemistry and physics owing to their fascinating property profile. The past few years have witnessed inspiringly progressing development in controlled fabrication of large-sized and single-crystal 2D materials. Among those production methods, chemical vapor deposition (CVD) has drawn the most attention because of its fine control over size and quality of 2D materials by modulating the growth conditions. Meanwhile, Cu has been widely accepted as the most popular catalyst due to its significant merit in growing monolayer 2D materials in the CVD process. Herein, very recent advances in preparing large-sized 2D single crystals on Cu substrates by CVD are presented. First, the unique features of Cu will be given in terms of ultralow precursor solubility and feasible surface engineering. Then, scaled growth of graphene and hexagonal boron nitride (h-BN) crystals on Cu substrates is demonstrated, wherein different kinds of Cu surfaces have been employed. Furthermore, the growth mechanism for the growth of 2D single crystals is exhibited, offering a guideline to elucidate the in-depth growth dynamics and kinetics. Finally, relevant issues for industrial-scale mass production of 2D single crystals are discussed and a promising future is expected.
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Affiliation(s)
- Yixuan Fan
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University and Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300072, China
| | - Lin Li
- Institute of Molecular Plus, Tianjin University, Tianjin, 300072, China
| | - Gui Yu
- Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Dechao Geng
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University and Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300072, China
| | - Xiaotao Zhang
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University and Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300072, China
- Institute of Molecular Aggregation Science, Tianjin University, Tianjin, 300072, China
| | - Wenping Hu
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University and Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300072, China
- Joint School of National University of Singapore and Tianjin University, Fuzhou International Campus, Tianjin University, Binhai New City, Fuzhou, 350207, China
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6
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Vats N, Wang Y, Sen S, Szilagyi S, Ochner H, Abb S, Burghard M, Sigle W, Kern K, van Aken PA, Rauschenbach S. Substrate-Selective Morphology of Cesium Iodide Clusters on Graphene. ACS NANO 2020; 14:4626-4635. [PMID: 32283013 PMCID: PMC7304923 DOI: 10.1021/acsnano.9b10053] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Formation and characterization of low-dimensional nanostructures is crucial for controlling the properties of two-dimensional (2D) materials such as graphene. Here, we study the structure of low-dimensional adsorbates of cesium iodide (CsI) on free-standing graphene using aberration-corrected transmission electron microscopy at atomic resolution. CsI is deposited onto graphene as charged clusters by electrospray ion-beam deposition. The interaction with the electron beam forms two-dimensional CsI crystals only on bilayer graphene, while CsI clusters consisting of 4, 6, 7, and 8 ions are exclusively observed on single-layer graphene. Chemical characterization by electron energy-loss spectroscopy imaging and precise structural measurements evidence the possible influence of charge transfer on the structure formation of the CsI clusters and layers, leading to different distances of the Cs and I to the graphene.
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Affiliation(s)
- Nilesh Vats
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - Yi Wang
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - Suman Sen
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - Sven Szilagyi
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - Hannah Ochner
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - Sabine Abb
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - Marko Burghard
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - Wilfried Sigle
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - Klaus Kern
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
- Institut
de Physique de la Matière Condensée, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Peter A. van Aken
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - Stephan Rauschenbach
- Max
Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
- Department
of Chemistry, University of Oxford, Oxford, OX1 3TA, United Kingdom
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7
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Sinha S, Zhu T, France-Lanord A, Sheng Y, Grossman JC, Porfyrakis K, Warner JH. Atomic structure and defect dynamics of monolayer lead iodide nanodisks with epitaxial alignment on graphene. Nat Commun 2020; 11:823. [PMID: 32041958 PMCID: PMC7010709 DOI: 10.1038/s41467-020-14481-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 01/06/2020] [Indexed: 11/09/2022] Open
Abstract
Lead Iodide (PbI2) is a large bandgap 2D layered material that has potential for semiconductor applications. However, atomic level study of PbI2 monolayer has been limited due to challenges in obtaining thin crystals. Here, we use liquid exfoliation to produce monolayer PbI2 nanodisks (30-40 nm in diameter and > 99% monolayer purity) and deposit them onto suspended graphene supports to enable atomic structure study of PbI2. Strong epitaxial alignment of PbI2 monolayers with the underlying graphene lattice occurs, leading to a phase shift from the 1 T to 1 H structure to increase the level of commensuration in the two lattice spacings. The fundamental point vacancy and nanopore structures in PbI2 monolayers are directly imaged, showing rapid vacancy migration and self-healing. These results provide a detailed insight into the atomic structure of monolayer PbI2, and the impact of the strong van der Waals interaction with graphene, which has importance for future applications in optoelectronics.
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Affiliation(s)
- Sapna Sinha
- Department of Materials, University of Oxford, 16 Parks Road, Oxford, OX1 3PH, UK
| | - Taishan Zhu
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
| | - Arthur France-Lanord
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
| | - Yuewen Sheng
- Department of Materials, University of Oxford, 16 Parks Road, Oxford, OX1 3PH, UK
| | - Jeffrey C Grossman
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
| | - Kyriakos Porfyrakis
- Faculty of Engineering and Science, University of Greenwich, Central Avenue, Chatham Maritime, Kent, ME4 4TB, UK
| | - Jamie H Warner
- Department of Mechanical Engineering, University of Texas at Austin, 204 Dean Keeton Street, Austin, 78712, USA.
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8
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Gerkman MA, Lee JK, Li X, Zhang Q, Windley M, Fonseca MV, Lu Y, Warner JH, Han GGD. Direct Imaging of Individual Molecular Binding to Clean Nanopore Edges in 2D Monolayer MoS 2. ACS NANO 2020; 14:153-165. [PMID: 31747249 DOI: 10.1021/acsnano.9b06061] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We use annular dark-field scanning transmission electron microscopy (ADF-STEM) to study how solution-deposited molecules bind to the edges and surface regions around nanopores in MoS2 monolayers. Nanopores with clean atomically flat edges and controllable mean diameter were generated by time-dependent large-area electron beam exposure during an in situ heating process, ready for subsequent molecular attachment. An organic molecule was designed to have a dithiolane end group that binds to Mo-terminated sites and a ligand structure that incorporates a single transition metal atom (Pt) marker for ADF-STEM detection. Pt atoms were used to track molecular binding around zigzag edges of MoS2 and to predict the orientations and conformations of molecules upon binding. We found that the molecules preferred to reside on the surface of the MoS2, pointing inward when attaching to the edge, rather than dangling out from the edge into free space, which is attributed to van der Waals interactions between the aromatic core of the molecule and the MoS2 basal planes. These results help us understand the way solution-deposited single molecules attach to free-standing edges of 2D crystals and the influence of van der Waals forces in guiding molecular binding.
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Affiliation(s)
- Mihael A Gerkman
- Department of Chemistry , Brandeis University , 415 South Street , Waltham , Massachusetts 02453 , United States
| | - Ja Kyung Lee
- Department of Materials , University of Oxford , 16 Parks Road , Oxford , OX1 3PH , United Kingdom
| | - Xiang Li
- Department of Chemistry , Brandeis University , 415 South Street , Waltham , Massachusetts 02453 , United States
| | - Qianyang Zhang
- Department of Materials , University of Oxford , 16 Parks Road , Oxford , OX1 3PH , United Kingdom
| | - Maurice Windley
- Department of Chemistry , Brandeis University , 415 South Street , Waltham , Massachusetts 02453 , United States
| | - Maria V Fonseca
- Department of Chemistry , Brandeis University , 415 South Street , Waltham , Massachusetts 02453 , United States
| | - Yang Lu
- Department of Materials , University of Oxford , 16 Parks Road , Oxford , OX1 3PH , United Kingdom
| | - Jamie H Warner
- Department of Materials , University of Oxford , 16 Parks Road , Oxford , OX1 3PH , United Kingdom
| | - Grace G D Han
- Department of Chemistry , Brandeis University , 415 South Street , Waltham , Massachusetts 02453 , United States
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9
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Chen J, Ryu GH, Zhang Q, Wen Y, Tai KL, Lu Y, Warner JH. Spatially Controlled Fabrication and Mechanisms of Atomically Thin Nanowell Patterns in Bilayer WS 2 Using in Situ High Temperature Electron Microscopy. ACS NANO 2019; 13:14486-14499. [PMID: 31794193 DOI: 10.1021/acsnano.9b08220] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We show controlled production of atomically thin nanowells in bilayer WS2 using an in situ heating holder combined with a focused electron beam in a scanning transmission electron microscope (STEM). We systematically study the formation and evolvement mechanism involved in removing a single layer of WS2 within a bilayer region with 2 nm accuracy in location and without punching through to the other layer to create a hole. Best results are found when using a high temperature of 800 °C, because it enables thermally activated atomic migration and eliminates the interference from surface carbon contamination. We demonstrate precise control over spatial distributions with 5 nm accuracy of patterning and the width of nanowells adjustable by dose-dependent parameters. The mechanism of removing a monolayer of WS2 within a bilayer region is different than removing equivalent sections in a monolayer film due to the van der Waals interaction of the underlying remaining layer in the bilayer system that stabilizes the excess W atom stoichiometry within the edges of the nanowell structure and facilitates expansion. This study offers insights for the nanoengineering of nanowells in two-dimensional (2D) transitional metal dichalcogenides (TMDs), which could hold potential as selective traps to localize 2D reactions in molecules and ions, underpinning the broader utilization of 2D material membranes.
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Affiliation(s)
- Jun Chen
- Department of Materials , University of Oxford , Parks Road , Oxford OX1 3PH , United Kingdom
| | - Gyeong Hee Ryu
- Department of Materials , University of Oxford , Parks Road , Oxford OX1 3PH , United Kingdom
| | - Qianyang Zhang
- Department of Materials , University of Oxford , Parks Road , Oxford OX1 3PH , United Kingdom
| | - Yi Wen
- Department of Materials , University of Oxford , Parks Road , Oxford OX1 3PH , United Kingdom
| | - Kuo-Lun Tai
- Department of Materials , University of Oxford , Parks Road , Oxford OX1 3PH , United Kingdom
| | - Yang Lu
- Department of Materials , University of Oxford , Parks Road , Oxford OX1 3PH , United Kingdom
| | - Jamie H Warner
- Department of Materials , University of Oxford , Parks Road , Oxford OX1 3PH , United Kingdom
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10
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Wang S, Robertson A, Warner JH. Atomic structure of defects and dopants in 2D layered transition metal dichalcogenides. Chem Soc Rev 2018; 47:6764-6794. [DOI: 10.1039/c8cs00236c] [Citation(s) in RCA: 126] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Transmission electron microscopy can directly image the detailed atomic structure of layered transition metal dichalcogenides, revealing defects and dopants.
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Affiliation(s)
- Shanshan Wang
- Science and Technology on Advanced Ceramic Fibers and Composites Laboratory
- College of Aerospace Science and Engineering
- National University of Defense Technology
- Changsha 410073
- P. R. China
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11
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Wang S, Sawada H, Chen Q, Han GGD, Allen C, Kirkland AI, Warner JH. In Situ Atomic-Scale Studies of the Formation of Epitaxial Pt Nanocrystals on Monolayer Molybdenum Disulfide. ACS NANO 2017; 11:9057-9067. [PMID: 28806068 DOI: 10.1021/acsnano.7b03648] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Pt-nanocrystal:MoS2 hybrid materials have promising catalytic properties for hydrogen evolution, and understanding their detailed structures at the atomic scale is crucial to further development. Here, we use an in situ heating holder in an aberration-corrected transmission electron microscope to study the formation of Pt nanocrystals directly on the surface of monolayer MoS2 from a precursor on heating to 800 °C. Isolated single Pt atoms and small nanoclusters are observed after in situ heating, with two types of preferential alignment between the Pt nanocrystals and the underlying monolayer MoS2. Strain effects and thickness variations of the ultrasmall Pt nanocrystal supported on MoS2 are studied, revealing that single atomic planes are formed from a nonlayered face-centered cubic bulk Pt configuration with a lattice expansion of 7-10% compared to that of bulk Pt. The Pt nanocrystals are surrounded by an amorphous carbon layer and in some cases have etched the local surrounding MoS2 material after heating. Electron beam irradiation also initiates Pt nanocrystal etching of the local MoS2, and we study this process in real time at atomic resolution. These results show that the presence of carbon around the Pt nanocrystals does not affect their epitaxial relationship with the MoS2 lattice. Single Pt atoms within the carbon layer are also immobilized at high temperature. These results provide important insights into the formation of Pt:MoS2 hybrid materials.
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Affiliation(s)
- Shanshan Wang
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom
| | - Hidetaka Sawada
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom
- Electron Physical Sciences Imaging Centre, Diamond Lightsource Ltd, Harwell Science and Innovation Campus , Didcot, Oxfordshire OX11 0DE, United Kingdom
- JEOL UK Ltd. , Silver Court Watchmead, Welwyn Garden City, Hertfordshire AL7 1LT, United Kingdom
| | - Qu Chen
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom
| | - Grace G D Han
- Department of Materials Science and Engineering, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Christopher Allen
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom
- Electron Physical Sciences Imaging Centre, Diamond Lightsource Ltd, Harwell Science and Innovation Campus , Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Angus I Kirkland
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom
- Electron Physical Sciences Imaging Centre, Diamond Lightsource Ltd, Harwell Science and Innovation Campus , Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Jamie H Warner
- Department of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom
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