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Ma Y, Yang L, Li Y, Li H, Huang Y, Chen J. Synthesis of Cu 2-xSe-MoSe 2 Edge-Epitaxial Heterostructure for Efficient Electrocatalytic Hydrogen Evolution. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2308650. [PMID: 38078791 DOI: 10.1002/smll.202308650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 11/16/2023] [Indexed: 05/18/2024]
Abstract
The exposure of active edge sites of transition metal dichalcogenide (TMD) in TMD-based heterostructures is essential to enhance the catalytic activity toward electrochemical catalytic hydrogen evolution (HER). The construction of TMD-based edge-epitaxial heterostructures can maximally expose the active edge sites. However, owing to the 2D crystal structures, it remains a great challenge to vertically align layered TMDs on non-layered metal chalcogenides. Herein, the synthesis of Cu2-xSe-MoSe2 edge-epitaxial heterostructure is reported by a facile one-pot wet-chemical method. A high density of MoSe2 nanosheets grown vertically to the <111>Cu2-xSe on the surface of Cu2-xSe nanocrystals is observed. Such edge-epitaxial configuration allows the exposure of abundant active edge sites of MoSe2 and enhances the changer transfer between MoSe2 and Cu2-xSe. As a result, the obtained Cu2-xSe-MoSe2 epitaxial heterostructures show excellent HER performance as compared to that of Cu2-xSe@1T/2H-MoSe2 core@shell heterostructure with similar size. This work not only offers a novel approach for designing efficient electrochemical catalysis but also enriches the diversity of TMD-based heterostructures, holding promise for various applications in the future.
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Affiliation(s)
- Yanbo Ma
- College of Materials Science and Engineering, Sichuan University, Chengdu, 610065, China
| | - Lei Yang
- College of Materials Science and Engineering, Sichuan University, Chengdu, 610065, China
| | - Ye Li
- College of Materials Science and Engineering, Sichuan University, Chengdu, 610065, China
| | - Hai Li
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Nanjing Tech University, Nanjing, 211816, China
| | - Yanping Huang
- Center of Engineering Experimental Teaching, School of Chemical Engineering, Sichuan University, Chengdu, 610065, China
| | - Junze Chen
- College of Materials Science and Engineering, Sichuan University, Chengdu, 610065, China
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2
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Abdukayumov K, Mičica M, Ibrahim F, Vojáček L, Vergnaud C, Marty A, Veuillen JY, Mallet P, de Moraes IG, Dosenovic D, Gambarelli S, Maurel V, Wright A, Tignon J, Mangeney J, Ouerghi A, Renard V, Mesple F, Li J, Bonell F, Okuno H, Chshiev M, George JM, Jaffrès H, Dhillon S, Jamet M. Atomic-Layer Controlled Transition from Inverse Rashba-Edelstein Effect to Inverse Spin Hall Effect in 2D PtSe 2 Probed by THz Spintronic Emission. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2304243. [PMID: 38160244 DOI: 10.1002/adma.202304243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Revised: 11/09/2023] [Indexed: 01/03/2024]
Abstract
2D materials, such as transition metal dichalcogenides, are ideal platforms for spin-to-charge conversion (SCC) as they possess strong spin-orbit coupling (SOC), reduced dimensionality and crystal symmetries as well as tuneable band structure, compared to metallic structures. Moreover, SCC can be tuned with the number of layers, electric field, or strain. Here, SCC in epitaxially grown 2D PtSe2 by THz spintronic emission is studied since its 1T crystal symmetry and strong SOC favor SCC. High quality of as-grown PtSe2 layers is demonstrated, followed by in situ ferromagnet deposition by sputtering that leaves the PtSe2 unaffected, resulting in well-defined clean interfaces as evidenced with extensive characterization. Through this atomic growth control and using THz spintronic emission, the unique thickness-dependent electronic structure of PtSe2 allows the control of SCC. Indeed, the transition from the inverse Rashba-Edelstein effect (IREE) in 1-3 monolayers (ML) to the inverse spin Hall effect (ISHE) in multilayers (>3 ML) of PtSe2 enabling the extraction of the perpendicular spin diffusion length and relative strength of IREE and ISHE is demonstrated. This band structure flexibility makes PtSe2 an ideal candidate to explore the underlying mechanisms and engineering of the SCC as well as for the development of tuneable THz spintronic emitters.
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Affiliation(s)
- Khasan Abdukayumov
- CEA, CNRS, Université Grenoble Alpes, Grenoble INP, IRIG-Spintec, Grenoble, 38000, France
| | - Martin Mičica
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, Paris, 75005, France
| | - Fatima Ibrahim
- CEA, CNRS, Université Grenoble Alpes, Grenoble INP, IRIG-Spintec, Grenoble, 38000, France
| | - Libor Vojáček
- CEA, CNRS, Université Grenoble Alpes, Grenoble INP, IRIG-Spintec, Grenoble, 38000, France
| | - Céline Vergnaud
- CEA, CNRS, Université Grenoble Alpes, Grenoble INP, IRIG-Spintec, Grenoble, 38000, France
| | - Alain Marty
- CEA, CNRS, Université Grenoble Alpes, Grenoble INP, IRIG-Spintec, Grenoble, 38000, France
| | - Jean-Yves Veuillen
- CNRS, Université Grenoble Alpes, Grenoble INP-UGA, Institut NéeL, Grenoble, 38000, France
| | - Pierre Mallet
- CNRS, Université Grenoble Alpes, Grenoble INP-UGA, Institut NéeL, Grenoble, 38000, France
| | | | | | - Serge Gambarelli
- CEA, CNRS, IRIG-SYMMES, Université Grenoble Alpes, Grenoble, 38000, France
| | - Vincent Maurel
- CEA, CNRS, IRIG-SYMMES, Université Grenoble Alpes, Grenoble, 38000, France
| | - Adrien Wright
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, Paris, 75005, France
| | - Jérôme Tignon
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, Paris, 75005, France
| | - Juliette Mangeney
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, Paris, 75005, France
| | - Abdelkarim Ouerghi
- CNRS, Centre de Nanosciences et de Nanotechnologies, Université Paris-Saclay, Palaiseau, 91120, France
| | - Vincent Renard
- CEA, IRIG-Pheliqs, Université Grenoble Alpes, Grenoble, 38000, France
| | - Florie Mesple
- CEA, IRIG-Pheliqs, Université Grenoble Alpes, Grenoble, 38000, France
| | - Jing Li
- CEA, Leti, Université Grenoble Alpes, Grenoble, 38000, France
| | - Frédéric Bonell
- CEA, CNRS, Université Grenoble Alpes, Grenoble INP, IRIG-Spintec, Grenoble, 38000, France
| | - Hanako Okuno
- CEA, IRIG-MEM, Université Grenoble Alpes, Grenoble, 38000, France
| | - Mairbek Chshiev
- CEA, CNRS, Université Grenoble Alpes, Grenoble INP, IRIG-Spintec, Grenoble, 38000, France
- Institut Universitaire de France, Paris, 75231, France
| | - Jean-Marie George
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, Palaiseau, F-91767, France
| | - Henri Jaffrès
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, Palaiseau, F-91767, France
| | - Sukhdeep Dhillon
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, Paris, 75005, France
| | - Matthieu Jamet
- CEA, CNRS, Université Grenoble Alpes, Grenoble INP, IRIG-Spintec, Grenoble, 38000, France
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3
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Lv H, da Silva A, Figueroa AI, Guillemard C, Aguirre IF, Camosi L, Aballe L, Valvidares M, Valenzuela SO, Schubert J, Schmidbauer M, Herfort J, Hanke M, Trampert A, Engel-Herbert R, Ramsteiner M, Lopes JMJ. Large-Area Synthesis of Ferromagnetic Fe 5- x GeTe 2 /Graphene van der Waals Heterostructures with Curie Temperature above Room Temperature. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2302387. [PMID: 37231567 DOI: 10.1002/smll.202302387] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 05/10/2023] [Indexed: 05/27/2023]
Abstract
Van der Waals (vdW) heterostructures combining layered ferromagnets and other 2D crystals are promising building blocks for the realization of ultracompact devices with integrated magnetic, electronic, and optical functionalities. Their implementation in various technologies depends strongly on the development of a bottom-up scalable synthesis approach allowing for realizing highly uniform heterostructures with well-defined interfaces between different 2D-layered materials. It is also required that each material component of the heterostructure remains functional, which ideally includes ferromagnetic order above room temperature for 2D ferromagnets. Here, it is demonstrated that the large-area growth of Fe5- x GeTe2 /graphene heterostructures is achieved by vdW epitaxy of Fe5- x GeTe2 on epitaxial graphene. Structural characterization confirms the realization of a continuous vdW heterostructure film with a sharp interface between Fe5- x GeTe2 and graphene. Magnetic and transport studies reveal that the ferromagnetic order persists well above 300 K with a perpendicular magnetic anisotropy. In addition, epitaxial graphene on SiC(0001) continues to exhibit a high electronic quality. These results represent an important advance beyond nonscalable flake exfoliation and stacking methods, thus marking a crucial step toward the implementation of ferromagnetic 2D materials in practical applications.
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Affiliation(s)
- Hua Lv
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V, 10117, Berlin, Germany
| | - Alessandra da Silva
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V, 10117, Berlin, Germany
| | - Adriana I Figueroa
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, Barcelona, 08193, Spain
| | - Charles Guillemard
- ALBA Synchrotron Light Source, Cerdanyola del Valles, Barcelona, 08290, Spain
| | - Iván Fernández Aguirre
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, Barcelona, 08193, Spain
- Universitat Autònoma de Barcelona, Bellaterra, Barcelona, 08193, Spain
| | - Lorenzo Camosi
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, Barcelona, 08193, Spain
| | - Lucia Aballe
- ALBA Synchrotron Light Source, Cerdanyola del Valles, Barcelona, 08290, Spain
| | - Manuel Valvidares
- ALBA Synchrotron Light Source, Cerdanyola del Valles, Barcelona, 08290, Spain
| | - Sergio O Valenzuela
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, Barcelona, 08193, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, 08010, Spain
| | - Jürgen Schubert
- Peter Grünberg Institut (PGI-9), Forschungszentrum Jülich, 52425, Jülich, Germany
- JARA-Fundamentals of Future Information Technology, Jülich-Aachen Research Alliance, 52425, Jülich, Germany
| | | | - Jens Herfort
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V, 10117, Berlin, Germany
| | - Michael Hanke
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V, 10117, Berlin, Germany
| | - Achim Trampert
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V, 10117, Berlin, Germany
| | - Roman Engel-Herbert
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V, 10117, Berlin, Germany
| | - Manfred Ramsteiner
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V, 10117, Berlin, Germany
| | - Joao Marcelo J Lopes
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V, 10117, Berlin, Germany
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4
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Buß L, Braud N, Ewert M, Jugovac M, Menteş TO, Locatelli A, Falta J, Flege JI. Unraveling van der Waals epitaxy: A real-time in-situ study of MoSe2 growth on graphene/Ru(0001). Ultramicroscopy 2023; 250:113749. [PMID: 37186986 DOI: 10.1016/j.ultramic.2023.113749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Revised: 03/31/2023] [Accepted: 05/04/2023] [Indexed: 05/17/2023]
Abstract
In the present work we investigate the growth of monolayer MoSe2 on selenium-intercalated graphene on Ru(0001), a model layered heterostructure combining a transition metal dichalcogenide with graphene, using low energy electron microscopy and micro-diffraction. Real-time observation of MoSe2 on graphene growth reveals the island nucleation dynamics at the nanoscale. Upon annealing, larger islands are formed by sliding and attachment of multiple nanometer-sized MoSe2 flakes. Local micro-spot angle-resolved photoemission spectroscopy reveals the electronic structure of the heterostructure, indicating that no charge transfer occurs within adjacent layers. The observed behavior is attributed to intercalation of Se at the graphene/Ru(0001) interface. The unperturbed nature of the proposed heterostructure therefore renders it as a model system for investigations of graphene supported TMD nanostructures.
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Affiliation(s)
- Lars Buß
- Applied Physics and Semiconductor Spectroscopy, Brandenburg University of Technology Cottbus-Senftenberg, Konrad-Zuse-Straße 1, Cottbus 03046, Germany.
| | - Nicolas Braud
- Institute of Solid State Physics, University of Bremen, Otto-Hahn-Allee 1, Bremen 28359, Germany
| | - Moritz Ewert
- Applied Physics and Semiconductor Spectroscopy, Brandenburg University of Technology Cottbus-Senftenberg, Konrad-Zuse-Straße 1, Cottbus 03046, Germany
| | - Matteo Jugovac
- Elettra-Sincrotrone Trieste S.C.p.A, S.S. 14km 163.5 in AREA Science Park, Trieste, Italy
| | - Tevfik Onur Menteş
- Elettra-Sincrotrone Trieste S.C.p.A, S.S. 14km 163.5 in AREA Science Park, Trieste, Italy
| | - Andrea Locatelli
- Elettra-Sincrotrone Trieste S.C.p.A, S.S. 14km 163.5 in AREA Science Park, Trieste, Italy
| | - Jens Falta
- Institute of Solid State Physics, University of Bremen, Otto-Hahn-Allee 1, Bremen 28359, Germany; MAPEX Center for Materials and Processes, P.O. Box 303 440, 28334, Bremen, Germany
| | - Jan Ingo Flege
- Applied Physics and Semiconductor Spectroscopy, Brandenburg University of Technology Cottbus-Senftenberg, Konrad-Zuse-Straße 1, Cottbus 03046, Germany
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5
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Weng X, David P, Guisset V, Martinelli L, Geaymond O, Coraux J, Renaud G. Superstructures, Commensurations, and Rotation of Single-Layer TaS 2 on Au(111) Induced by Cs Intercalation/Deintercalation. ACS NANO 2023; 17:5459-5471. [PMID: 36912862 DOI: 10.1021/acsnano.2c10655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
We use in situ synchrotron grazing incidence X-ray diffraction and X-ray reflectivity to investigate with high resolution the structure of a two-dimensional single layer of tantalum sulfide grown on a Au(111) surface and its evolution during intercalation by Cs atoms and deintercalation, which decouples and recouples the two materials, respectively. The grown single layer consists of a mixture of TaS2 and its S-depleted version, TaS, both aligned with gold, and forming moirés where 7 (respectively 13) lattice constants of the 2D layer almost perfectly match 8 (respectively 15) substrate lattice constants. Intercalation fully decouples the system by lifting the single layer by ∼370 pm and induces an increase of its lattice parameter by 1-2 picometers. The system gradually evolves, during cycles of intercalation/deintercalation assisted by an H2S atmosphere, toward a final coupled state consisting of the fully stoichiometric TaS2 dichalcogenide whose moiré is found very close to the 7/8 commensurability. The reactive H2S atmosphere appears necessary to achieve full deintercalation, presumably by preventing S depletion and the concomitant strong bonding with the intercalant. The structural quality of the layer improves during the cyclic treatment. In parallel, because they are decoupled from the substrate by the intercalation of cesium, some of the TaS2 flakes rotate by 30°. These produce two additional superlattices with characteristic diffraction patterns of different origins. The first is aligned with gold's high symmetry crystallographic directions and is a commensurate moiré ((6 × 6)-Au(111) coinciding with (3√3 × 3√3)R30°-TaS2). The second is incommensurate and corresponds to a near coincidence of (6 × 6) unit cells of 30°-rotated TaS2 with (4√3 × 4√3)Au(111) surface ones. This structure, which is less coupled to gold, might be related to the ∼(3× 3) charge density wave previously reported even at room temperature in TaS2 grown on noninteracting substrates. A (3 × 3) superstructure of 30°-rotated TaS2 islands is indeed revealed by complementary scanning tunneling microscopy.
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Affiliation(s)
- Xiaorong Weng
- Université Grenoble Alpes, CEA, IRIG/MEM/NRS, 38000 Grenoble, France
| | - Philippe David
- Université Grenoble Alpes, CNRS, Institut NEEL, 38000 Grenoble, France
| | - Valérie Guisset
- Université Grenoble Alpes, CNRS, Institut NEEL, 38000 Grenoble, France
| | - Lucio Martinelli
- Université Grenoble Alpes, CNRS, Institut NEEL, 38000 Grenoble, France
| | - Olivier Geaymond
- Université Grenoble Alpes, CNRS, Institut NEEL, 38000 Grenoble, France
| | - Johann Coraux
- Université Grenoble Alpes, CNRS, Institut NEEL, 38000 Grenoble, France
| | - Gilles Renaud
- Université Grenoble Alpes, CEA, IRIG/MEM/NRS, 38000 Grenoble, France
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6
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Lu H, Liu W, Wang H, Liu X, Zhang Y, Yang D, Pi X. Molecular beam epitaxy growth and scanning tunneling microscopy study of 2D layered materials on epitaxial graphene/silicon carbide. NANOTECHNOLOGY 2023; 34:132001. [PMID: 36563353 DOI: 10.1088/1361-6528/acae28] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 12/23/2022] [Indexed: 06/17/2023]
Abstract
Since the advent of atomically flat graphene, two-dimensional (2D) layered materials have gained extensive interest due to their unique properties. The 2D layered materials prepared on epitaxial graphene/silicon carbide (EG/SiC) surface by molecular beam epitaxy (MBE) have high quality, which can be directly applied without further transfer to other substrates. Scanning tunneling microscopy and spectroscopy (STM/STS) with high spatial resolution and high-energy resolution are often used to study the morphologies and electronic structures of 2D layered materials. In this review, recent progress in the preparation of various 2D layered materials that are either monoelemental or transition metal dichalcogenides on EG/SiC surface by MBE and their STM/STS investigations are introduced.
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Affiliation(s)
- Hui Lu
- State Key Laboratory of Silicon Materials & School of Materials Science and Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, People's Republic of China
- Institute of Advanced Semiconductors & Zhejiang Provincial Key Laboratory of Power Semiconductor Materials and Devices, ZJU-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou, Zhejiang 311200, People's Republic of China
| | - Wenji Liu
- State Key Laboratory of Silicon Materials & School of Materials Science and Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, People's Republic of China
| | - Haolin Wang
- State Key Laboratory of Silicon Materials & School of Materials Science and Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, People's Republic of China
| | - Xiao Liu
- State Key Laboratory of Silicon Materials & School of Materials Science and Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, People's Republic of China
- Institute of Advanced Semiconductors & Zhejiang Provincial Key Laboratory of Power Semiconductor Materials and Devices, ZJU-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou, Zhejiang 311200, People's Republic of China
| | - Yiqiang Zhang
- School of Materials Science and Engineering & College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, People's Republic of China
| | - Deren Yang
- State Key Laboratory of Silicon Materials & School of Materials Science and Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, People's Republic of China
- Institute of Advanced Semiconductors & Zhejiang Provincial Key Laboratory of Power Semiconductor Materials and Devices, ZJU-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou, Zhejiang 311200, People's Republic of China
| | - Xiaodong Pi
- State Key Laboratory of Silicon Materials & School of Materials Science and Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, People's Republic of China
- Institute of Advanced Semiconductors & Zhejiang Provincial Key Laboratory of Power Semiconductor Materials and Devices, ZJU-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou, Zhejiang 311200, People's Republic of China
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7
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Salazar R, Varotto S, Vergnaud C, Garcia V, Fusil S, Chaste J, Maroutian T, Marty A, Bonell F, Pierucci D, Ouerghi A, Bertran F, Le Fèvre P, Jamet M, Bibes M, Rault J. Visualizing Giant Ferroelectric Gating Effects in Large-Scale WSe 2/BiFeO 3 Heterostructures. NANO LETTERS 2022; 22:9260-9267. [PMID: 36394996 DOI: 10.1021/acs.nanolett.2c02448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Multilayers based on quantum materials (complex oxides, topological insulators, transition-metal dichalcogenides, etc.) have enabled the design of devices that could revolutionize microelectronics and optoelectronics. However, heterostructures incorporating quantum materials from different families remain scarce, while they would immensely broaden the range of possible applications. Here we demonstrate the large-scale integration of compounds from two highly multifunctional families: perovskite oxides and transition-metal dichalcogenides (TMDs). We couple BiFeO3, a room-temperature multiferroic oxide, and WSe2, a semiconducting two-dimensional material with potential for photovoltaics and photonics. WSe2 is grown by molecular beam epitaxy and transferred on a centimeter-scale onto BiFeO3 films. Using angle-resolved photoemission spectroscopy, we visualize the electronic structure of 1 to 3 monolayers of WSe2 and evidence a giant energy shift as large as 0.75 eV induced by the ferroelectric polarization direction in the underlying BiFeO3. Such a strong shift opens new perspectives in the efficient manipulation of TMD properties by proximity effects.
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Affiliation(s)
- Raphaël Salazar
- Synchrotron SOLEIL, L'Orme des Merisiers, Départementale 128, F-91190Saint-Aubin, France
| | - Sara Varotto
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 1 avenue Augustin Fresnel, 91767Palaiseau, France
| | - Céline Vergnaud
- Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, IRIG-SPINTEC, 38000Grenoble, France
| | - Vincent Garcia
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 1 avenue Augustin Fresnel, 91767Palaiseau, France
| | - Stéphane Fusil
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 1 avenue Augustin Fresnel, 91767Palaiseau, France
| | - Julien Chaste
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, 91120Palaiseau, France
| | - Thomas Maroutian
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, 91120Palaiseau, France
| | - Alain Marty
- Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, IRIG-SPINTEC, 38000Grenoble, France
| | - Frédéric Bonell
- Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, IRIG-SPINTEC, 38000Grenoble, France
| | - Debora Pierucci
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, 91120Palaiseau, France
| | - Abdelkarim Ouerghi
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, 91120Palaiseau, France
| | - François Bertran
- Synchrotron SOLEIL, L'Orme des Merisiers, Départementale 128, F-91190Saint-Aubin, France
| | - Patrick Le Fèvre
- Synchrotron SOLEIL, L'Orme des Merisiers, Départementale 128, F-91190Saint-Aubin, France
| | - Matthieu Jamet
- Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, IRIG-SPINTEC, 38000Grenoble, France
| | - Manuel Bibes
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 1 avenue Augustin Fresnel, 91767Palaiseau, France
| | - Julien Rault
- Synchrotron SOLEIL, L'Orme des Merisiers, Départementale 128, F-91190Saint-Aubin, France
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8
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Khalil L, Pierucci D, Velez-Fort E, Avila J, Vergnaud C, Dudin P, Oehler F, Chaste J, Jamet M, Lhuillier E, Pala M, Ouerghi A. Hybridization and localized flat band in the WSe 2/MoSe 2heterobilayer. NANOTECHNOLOGY 2022; 34:045702. [PMID: 36252554 DOI: 10.1088/1361-6528/ac9abe] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 10/17/2022] [Indexed: 06/16/2023]
Abstract
Nearly localized moiré flat bands in momentum space, arising at particular twist angles, are the key to achieve correlated effects in transition-metal dichalcogenides. Here, we use angle-resolved photoemission spectroscopy (ARPES) to visualize the presence of a flat band near the Fermi level of van der Waals WSe2/MoSe2heterobilayer grown by molecular beam epitaxy. This flat band is localized near the Fermi level and has a width of several hundred meVs. By combining ARPES measurements with density functional theory calculations, we confirm the coexistence of different domains, namely the reference 2H stacking without layer misorientation and regions with arbitrary twist angles. For the 2H-stacked heterobilayer, our ARPES results show strong interlayer hybridization effects, further confirmed by complementary micro- Raman spectroscopy measurements. The spin-splitting of the valence band atKis determined to be 470 meV. The valence band maximum (VBM) position of the heterobilayer is located at the Γ point. The energy difference between the VBM at Γ and theKpoint is of -60 meV, which is a stark difference compared to individual single monolayer WSe2and monolayer WSe2, showing both a VBM atK.
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Affiliation(s)
- Lama Khalil
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, F-91120, Palaiseau, France
| | - Debora Pierucci
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, F-91120, Palaiseau, France
| | - Emilio Velez-Fort
- Université Grenoble Alpes, CEA, CNRS, Grenoble INP, IRIG-Spintec, F-38054, Grenoble, France
| | - José Avila
- Synchrotron-SOLEIL, Université Paris-Saclay, Saint-Aubin, BP48, F-91192 Gif sur Yvette, France
| | - Céline Vergnaud
- Université Grenoble Alpes, CEA, CNRS, Grenoble INP, IRIG-Spintec, F-38054, Grenoble, France
| | - Pavel Dudin
- Synchrotron-SOLEIL, Université Paris-Saclay, Saint-Aubin, BP48, F-91192 Gif sur Yvette, France
| | - Fabrice Oehler
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, F-91120, Palaiseau, France
| | - Julien Chaste
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, F-91120, Palaiseau, France
| | - Matthieu Jamet
- Université Grenoble Alpes, CEA, CNRS, Grenoble INP, IRIG-Spintec, F-38054, Grenoble, France
| | - Emmanuel Lhuillier
- Sorbonne Université, CNRS, Institut des NanoSciences de Paris, INSP, F-75005 Paris, France
| | - Marco Pala
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, F-91120, Palaiseau, France
| | - Abdelkarim Ouerghi
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, F-91120, Palaiseau, France
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9
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Two-dimensional materials prospects for non-volatile spintronic memories. Nature 2022; 606:663-673. [PMID: 35732761 DOI: 10.1038/s41586-022-04768-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 04/19/2022] [Indexed: 01/12/2023]
Abstract
Non-volatile magnetic random-access memories (MRAMs), such as spin-transfer torque MRAM and next-generation spin-orbit torque MRAM, are emerging as key to enabling low-power technologies, which are expected to spread over large markets from embedded memories to the Internet of Things. Concurrently, the development and performances of devices based on two-dimensional van der Waals heterostructures bring ultracompact multilayer compounds with unprecedented material-engineering capabilities. Here we provide an overview of the current developments and challenges in regard to MRAM, and then outline the opportunities that can arise by incorporating two-dimensional material technologies. We highlight the fundamental properties of atomically smooth interfaces, the reduced material intermixing, the crystal symmetries and the proximity effects as the key drivers for possible disruptive improvements for MRAM at advanced technology nodes.
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10
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Chi Z, Zhang X, Wen X, Han J, Wei Z, Du L, Lai J, Wang X, Zhang G, Zhao Q, Chen H, Ajayan PM, Weng YX. Determining Quasiparticle Bandgap of Two-Dimensional Transition Metal Dichalcogenides by Observation of Hot Carrier Relaxation Dynamics. J Phys Chem Lett 2021; 12:585-591. [PMID: 33382603 DOI: 10.1021/acs.jpclett.0c03414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Using excitation-energy-scanning ultrafast infrared microspectroscopy, the excess energy-dependent hot carrier relaxation dynamics in atomically thin two-dimensional transition metal dichalcogenides (2D TMDs) after femtosecond photoexcitation was directly monitored. A good linear relationship between the carrier relaxation time and the excitation wavelength is observed for all measured monolayer (ML) and bilayer (BL) TMD samples, which allows us to determine their quasiparticle bandgaps as well as corresponding exciton binding energies. A carrier-optical-phonon scattering-mediated cascading-relaxation model is proposed, which can perfectly describe all the measured dynamics. As a consequence, the quasiparticle bandgaps of ML MoSe2, ML MoS2, BL MoSe2, and BL WSe2 are determined to be 2.07, 2.11, 1.67, and 1.81 eV, respectively. Our work reveals a general picture for the hot carrier relaxation dynamics in atomically thin TMDs and offers an effective experimental approach in probing the bandgaps of TMDs under ambient conditions.
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Affiliation(s)
- Zhen Chi
- The Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center for Quantum Technology Research, School of Physics, Beijing Institute of Technology, Beijing 100081, China
- Institute of Photo-biophysics, School of Physics and Electronics, Henan University, Kaifeng 475004, China
| | - Xiang Zhang
- Department of Materials Science and NanoEngineering, Rice University, 6100 Main Street, Houston, Texas 77005-1892, United States
| | - Xiewen Wen
- Department of Materials Science and NanoEngineering, Rice University, 6100 Main Street, Houston, Texas 77005-1892, United States
| | - Junfeng Han
- Key Lab of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), Beijing Key Lab of Nanophotonics & Ultrafine Optoelectronic Systems, and School of Physics, Beijing Institute of Technology, Beijing 100081, China
- Micronano Center, Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing 100081, China
| | - Zheng Wei
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Luojun Du
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jiawei Lai
- Department of Materials Science and NanoEngineering, Rice University, 6100 Main Street, Houston, Texas 77005-1892, United States
| | - Xiangzhuo Wang
- Key Lab of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), Beijing Key Lab of Nanophotonics & Ultrafine Optoelectronic Systems, and School of Physics, Beijing Institute of Technology, Beijing 100081, China
- Micronano Center, Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing 100081, China
| | - Guangyu Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qing Zhao
- Center for Quantum Technology Research, School of Physics, Beijing Institute of Technology, Beijing 100081, China
| | - Hailong Chen
- The Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Pulickel M Ajayan
- Department of Materials Science and NanoEngineering, Rice University, 6100 Main Street, Houston, Texas 77005-1892, United States
| | - Yu-Xiang Weng
- The Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
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11
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Dai TJ, Chen YQ, Zhou ZY, Sun J, Peng XS, Liu XZ. Two-dimensional MoSe2/graphene heterostructure thin film with wafer-scale continuity via van der Waals epitaxy. Chem Phys Lett 2020. [DOI: 10.1016/j.cplett.2020.137762] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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12
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Mortelmans W, Nalin Mehta A, Balaji Y, Sergeant S, Meng R, Houssa M, De Gendt S, Heyns M, Merckling C. On the van der Waals Epitaxy of Homo-/Heterostructures of Transition Metal Dichalcogenides. ACS APPLIED MATERIALS & INTERFACES 2020; 12:27508-27517. [PMID: 32447952 DOI: 10.1021/acsami.0c05872] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Layered materials held together by weak van der Waals (vdW) interactions are a promising class of materials in the field of nanotechnology. Besides the potential for single layers, stacking of various vdW layers becomes even more promising since unique properties can hence be precisely engineered. The synthesis of stacked vdW layers, however, remains to date, hardly understood. Therefore, in this work, the vdW epitaxy of transition metal dichalcogenides (TMDs) on single-crystalline TMD templates is investigated in depth. It is demonstrated that the role of lattice mismatch is insignificant. More importantly is the role of surface energy, calculated using density functional theory, which plays an essential role in the activation energy for adatom diffusion, hence nucleation density. This in turn correlates with defect density since the stacking sequence in vdW epitaxy is generally poorly controlled. Moreover, the vapor pressure of the transition metal is also found to correlate with adatom diffusion. Consequently, the proposed study enables important and new insight in the vdW epitaxy of multilayer 2D homo-/heterostructures.
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Affiliation(s)
- Wouter Mortelmans
- Department of Materials Engineering, KU Leuven, Kasteelpark Arenberg 44, 3001 Leuven, Belgium
- Imec, Kapeldreef 75, 3001 Leuven, Belgium
| | - Ankit Nalin Mehta
- Imec, Kapeldreef 75, 3001 Leuven, Belgium
- Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200d, 3001 Leuven, Belgium
| | - Yashwanth Balaji
- Imec, Kapeldreef 75, 3001 Leuven, Belgium
- Department of Electrical Engineering, KU Leuven, Kasteelpark Arenberg 10, 3001 Leuven, Belgium
| | | | - Ruishen Meng
- Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200d, 3001 Leuven, Belgium
| | - Michel Houssa
- Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200d, 3001 Leuven, Belgium
| | - Stefan De Gendt
- Imec, Kapeldreef 75, 3001 Leuven, Belgium
- Department of Chemistry, KU Leuven, Celestijnenlaan 200f, 3001 Leuven, Belgium
| | - Marc Heyns
- Department of Materials Engineering, KU Leuven, Kasteelpark Arenberg 44, 3001 Leuven, Belgium
- Imec, Kapeldreef 75, 3001 Leuven, Belgium
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13
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Dappe YJ, Almadori Y, Dau MT, Vergnaud C, Jamet M, Paillet C, Journot T, Hyot B, Pochet P, Grévin B. Charge transfers and charged defects in WSe 2/graphene-SiC interfaces. NANOTECHNOLOGY 2020; 31:255709. [PMID: 32182596 DOI: 10.1088/1361-6528/ab8083] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We report on Kelvin probe force microscopy (KPFM) and density functional theory (DFT) investigations of charge transfers in vertical heterojunctions between tungsten diselenide (WSe2) layers and graphene on silicon carbide substrates. The experimental data reveal the existence of an interface dipole, which is shown by DFT to originate from the neutralization of the graphene n-doping by an electron transfer towards the transition metal dichalcogenide (TMD) layer. The relative vacuum level shift probed by KPFM between the TMD and the substrate stays constant when passing from monolayer to bilayer graphene, which confirms that the Schottky-Mott model can be rigorously applied to these interfaces by taking into account the charge transfer from the substrate to the TMD. DFT calculations show that the first TMD layer absorbs almost all the excess charges contained in the graphene, and that the second TMD layer shall not play a significant role in the electrostatics of the system. Negatively charged defect at the TMD edges contribute however to the electrostatic landscape probed by KPFM on both TMD layers.
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Affiliation(s)
- Y J Dappe
- SPEC, CEA, CNRS, Université Paris Saclay, CEA Saclay, 91191 Gif-sur-Yvette Cedex France
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14
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Abstract
The Hall effect can be extended by inducing a temperature gradient in lieu of electric field that is known as the Nernst (-Ettingshausen) effect. The recently discovered spin Nernst effect in heavy metals continues to enrich the picture of Nernst effect-related phenomena. However, the collection would not be complete without mentioning the valley degree of freedom benchmarked by the valley Hall effect. Here we show the experimental evidence of its missing counterpart, the valley Nernst effect. Using millimeter-sized WSe\documentclass[12pt]{minimal}
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\begin{document}$${}_{2}$$\end{document}2 mono-multi-layers and the ferromagnetic resonance-spin pumping technique, we are able to apply a temperature gradient by off-centering the sample in the radio frequency cavity and address a single valley through spin-valley coupling. The combination of a temperature gradient and the valley polarization leads to the valley Nernst effect in WSe\documentclass[12pt]{minimal}
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\begin{document}$${}_{2}$$\end{document}2 that we detect electrically at room temperature. The valley Nernst coefficient is in good agreement with the predicted value. Atomically thin transition metal dichalcogenides possess a valley degree of freedom, which could enrich the physics underpinning the conventional Nernst effect observed in traditional solids. Here, the authors report experimental evidence of the valley Nernst effect in WSe2 at room temperature.
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15
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Abstract
Within the framework of 2D materials, we present four theoretical models of a vertical field-effect transistor (FET) composed of simple alternate graphene and MoS2 layers. The electronic transport properties at a specific graphene/MoS2 interface in each configuration are investigated by focusing in particular on the current as a function of the gate voltage. The gate voltage, simulated with a shift of the bands of a specific layer, allows us to tune the current at the interface and the charge transfer between the planes. This analysis of the charge transfer as a function of the gate voltage reveals a strong connection with the transport characteristics as the slope of the current curve. The analysis of physical phenomena at the graphene/MoS2 interface can further improve the 2D vertical FET performance and contribute to the development of new 2D nanotechnology.
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Affiliation(s)
- D Di Felice
- Service de Physique de l'Etat Condensé, DSM/IRAMIS/SPEC, CNRS UMR 3680, CEA Saclay, Université Paris-Saclay, F-91191 Gif-Sur-Yvette, France
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16
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Batzill M. Mirror twin grain boundaries in molybdenum dichalcogenides. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:493001. [PMID: 30457114 DOI: 10.1088/1361-648x/aae9cf] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Mirror twin grain boundaries (MTBs) exist at the interface between two grains of 60° rotated hexagonal transition metal dichalcogenides (TMDC). These grain boundaries form a regular atomic structure that extends in one dimension and thus may be described as a one-dimensional (1D) lattice embedded in the 2D TMDC. In this review, the different atomic structures and compositions of these MTBs are discussed. The obvious formation of MTBs is by coalescence of two twinned grains. In addition, however, in MoSe2 and MoTe2 a different formation mechanism has been revealed for the formation of Mo-rich MTBs. It has been shown that excess Mo can be incorporated into the TMDC lattices. These excess Mo atoms can then reorganize into closed, triangular MTB-loops that can grow in size by adding more Mo atoms to them. This mechanism allows the formation of dense MTB networks in MoSe2 and MoTe2. Such MTB networks have been observed in samples grown by molecular beam epitaxy (MBE) and consequently their presence needs to be considered in understanding the properties of MBE grown MoSe2 and MoTe2. Density functional theory as well as photoemission spectroscopy of MTB networks have shown that MTBs exhibit dispersing 1D-bands that intersect the Fermi-level, thus suggesting that these are 1D electron systems. Consequently, experimental data have been interpreted to reveal a charge density wave (or Peierls) instability, as well as a Tomonaga-Luttinger liquid behavior for electrons confined in 1D. We discuss these observations and the controversies that remain in the interpretation of some data. The metallic properties of the MTBs and their formation in dense networks also sparked the potential use of such crystal modifications for making metallic contacts to MoTe2 or MoSe2. Moreover, these crystal modifications may also boost the catalytic properties of these materials.
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Affiliation(s)
- Matthias Batzill
- Department of Physics, University of South Florida, Tampa, FL 33620, United States of America
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17
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Cattelan M, Fox NA. A Perspective on the Application of Spatially Resolved ARPES for 2D Materials. NANOMATERIALS (BASEL, SWITZERLAND) 2018; 8:E284. [PMID: 29702567 PMCID: PMC5977298 DOI: 10.3390/nano8050284] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 04/20/2018] [Accepted: 04/23/2018] [Indexed: 12/13/2022]
Abstract
In this paper, a perspective on the application of Spatially- and Angle-Resolved PhotoEmission Spectroscopy (ARPES) for the study of two-dimensional (2D) materials is presented. ARPES allows the direct measurement of the electronic band structure of materials generating extremely useful insights into their electronic properties. The possibility to apply this technique to 2D materials is of paramount importance because these ultrathin layers are considered fundamental for future electronic, photonic and spintronic devices. In this review an overview of the technical aspects of spatially localized ARPES is given along with a description of the most advanced setups for laboratory and synchrotron-based equipment. This technique is sensitive to the lateral dimensions of the sample. Therefore, a discussion on the preparation methods of 2D material is presented. Some of the most interesting results obtained by ARPES are reported in three sections including: graphene, transition metal dichalcogenides (TMDCs) and 2D heterostructures. Graphene has played a key role in ARPES studies because it inspired the use of this technique with other 2D materials. TMDCs are presented for their peculiar transport, optical and spin properties. Finally, the section featuring heterostructures highlights a future direction for research into 2D material structures.
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Affiliation(s)
- Mattia Cattelan
- School of Chemistry, University of Bristol, Cantocks Close, Bristol BS8 1TS, UK; .
| | - Neil A Fox
- School of Chemistry, University of Bristol, Cantocks Close, Bristol BS8 1TS, UK; .
- H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, UK.
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