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Yan J, Ye K, Jia Z, Zhang Z, Li P, Liu L, Mu C, Huang H, Cheng Y, Nie A, Xiang J, Wang S, Liu Z. High-Performance Broadband Image Sensing Photodetector Based on MnTe/WS 2 van der Waals Epitaxial Heterostructures. ACS APPLIED MATERIALS & INTERFACES 2024; 16:19112-19120. [PMID: 38579811 DOI: 10.1021/acsami.4c00159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/07/2024]
Abstract
Two-dimensional transition metal dichalcogenide (TMDC) heterostructure is receiving considerable attention due to its novel electronic, optoelectronic, and spintronic devices with design-oriented and functional features. However, direct design and synthesis of high-quality TMDC/MnTe heterostructures remain difficult, which severely impede further investigations of semiconductor/magnetic semiconductor devices. Herein, the synthesis of high-quality vertically stacked WS2/MnTe heterostructures is realized via a two-step chemical vapor deposition method. Raman, photoluminescence, and scanning transmission electron microscopy characterizations reveal the high-quality and atomically sharp interfaces of the WS2/MnTe heterostructure. WS2/MnTe-based van der Waals field effect transistors demonstrate high rectification behavior with rectification ratio up to 106, as well as a typical p-n electrical transport characteristic. Notably, the fabricated WS2/MnTe photodetector exhibits sensitive and broadband photoresponse ranging from UV to NIR with a maximum responsivity of 1.2 × 103 A/W, a high external quantum efficiency of 2.7 × 105%, and fast photoresponse time of ∼50 ms. Moreover, WS2/MnTe heterostructure photodetectors possess a broadband image sensing capability at room temperature, suggesting potential applications in next-generation high-performance and broadband image sensing photodetectors.
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Affiliation(s)
- Junxin Yan
- Center for High Pressure Science (CHiPS), State Key Laboratory of Metastable Materials Science & Technology, Yanshan University, Qinhuangdao 066004, China
| | - Kun Ye
- Center for High Pressure Science (CHiPS), State Key Laboratory of Metastable Materials Science & Technology, Yanshan University, Qinhuangdao 066004, China
- Anhui Key Laboratory of Magnetic Functional Materials and Devices, School of Materials Science and Engineering, Anhui University, Hefei 230601, China
- Institute of Quantum Materials and Devices, School of Electronics and Information Engineering, Tiangong University, Tianjin 300387, China
| | - Zhiyan Jia
- Institute of Quantum Materials and Devices, School of Electronics and Information Engineering, Tiangong University, Tianjin 300387, China
| | - Zeyu Zhang
- Beijing Advanced Innovation Center for Materials Genome Engineering, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Penghui Li
- Center for High Pressure Science (CHiPS), State Key Laboratory of Metastable Materials Science & Technology, Yanshan University, Qinhuangdao 066004, China
| | - Lixuan Liu
- Institute of Quantum Materials and Devices, School of Electronics and Information Engineering, Tiangong University, Tianjin 300387, China
| | - Congpu Mu
- Center for High Pressure Science (CHiPS), State Key Laboratory of Metastable Materials Science & Technology, Yanshan University, Qinhuangdao 066004, China
| | - He Huang
- Beijing Advanced Innovation Center for Materials Genome Engineering, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Yingchun Cheng
- Center for High Pressure Science (CHiPS), State Key Laboratory of Metastable Materials Science & Technology, Yanshan University, Qinhuangdao 066004, China
| | - Anmin Nie
- Center for High Pressure Science (CHiPS), State Key Laboratory of Metastable Materials Science & Technology, Yanshan University, Qinhuangdao 066004, China
| | - Jianyong Xiang
- Center for High Pressure Science (CHiPS), State Key Laboratory of Metastable Materials Science & Technology, Yanshan University, Qinhuangdao 066004, China
| | - Shouguo Wang
- Anhui Key Laboratory of Magnetic Functional Materials and Devices, School of Materials Science and Engineering, Anhui University, Hefei 230601, China
| | - Zhongyuan Liu
- Center for High Pressure Science (CHiPS), State Key Laboratory of Metastable Materials Science & Technology, Yanshan University, Qinhuangdao 066004, China
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Gontijo RN, Bunker N, Graiser SL, Ding X, Smeu M, Elías AL. Resonant Raman Scattering Study of Strain and Defects in Chemical Vapor Deposition Grown MoS 2 Monolayers. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2310685. [PMID: 38558523 DOI: 10.1002/smll.202310685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 01/23/2024] [Indexed: 04/04/2024]
Abstract
The development of bottom-up synthesis routes for semiconducting transition metal dichalcogenides (TMDs) and the assessment of their defects are of paramount importance to achieve their applications. TMD monolayers grown by chemical vapor deposition (CVD) can be subjected to significant strain and, here, Raman and photoluminescence spectroscopies are combined to characterize strain in over one hundred MoS2 monolayer samples grown by CVD. The frequency changes of phonons as a function of strain are analyzed, and used to extract the Grüneisen parameter of both zone-center and edge phonons. Additionally, the intensity of the defect-induced longitudinal acoustic (LA) and transverse acoustic (TA) Raman bands are discussed in relation to strain and electronic doping. The experimental mode-Grüneisen parameters obtained are compared with those calculated by density functional theory (DFT), to better characterize the type of strain and its resulting effects on Grüneisen parameters. The findings indicate that the use of Raman spectra to determine defect densities in 2D MoS2 must be always conducted considering strain effects. To the best of the authors' knowledge, this work constitutes the first report on double resonance Raman processes studied as a function of strain in 2D-MoS2. The new approach to obtain the Grüneisen parameter from zone-edge phonons in MoS2 can also be extended to other 2D semiconducting TMDs.
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Affiliation(s)
- Rafael N Gontijo
- Department of Physics, Binghamton University, Binghamton, NY, 13902, USA
| | - Nathaniel Bunker
- Department of Physics, Binghamton University, Binghamton, NY, 13902, USA
| | - Samarra L Graiser
- Department of Physics, Binghamton University, Binghamton, NY, 13902, USA
| | - Xintong Ding
- Department of Physics, Binghamton University, Binghamton, NY, 13902, USA
| | - Manuel Smeu
- Department of Physics, Binghamton University, Binghamton, NY, 13902, USA
| | - Ana Laura Elías
- Department of Physics, Binghamton University, Binghamton, NY, 13902, USA
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3
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Ge A, Ge X, Sun L, Lu X, Ma L, Zhao X, Yao B, Zhang X, Zhang T, Jing W, Zhou X, Shen X, Lu W. Unraveling the strain tuning mechanism of interlayer excitons in WSe 2/MoSe 2heterostructure. NANOTECHNOLOGY 2024; 35:175207. [PMID: 38266306 DOI: 10.1088/1361-6528/ad2232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 01/23/2024] [Indexed: 01/26/2024]
Abstract
Atomically thin transition metal dichalcogenides (TMDs) exhibit rich excitonic physics, due to reduced dielectric screening and strong Coulomb interactions. Especially, some attractive topics in modern condensed matter physics, such as correlated insulator, superconductivity, topological excitons bands, are recently reported in stacking two monolayer (ML) TMDs. Here, we clearly reveal the tuning mechanism of tensile strain on interlayer excitons (IEXs) and intralayer excitons (IAXs) in WSe2/MoSe2heterostructure (HS) at low temperature. We utilize the cryogenic tensile strain platform to stretch the HS, and measure by micro-photoluminescence (μ-PL). The PL peaks redshifts of IEXs and IAXs in WSe2/MoSe2HS under tensile strain are well observed. The first-principles calculations by using density functional theory reveals the PL peaks redshifts of IEXs and IAXs origin from bandgap shrinkage. The calculation results also show the Mo-4d states dominating conduction band minimum shifts of the ML MoSe2plays a dominant role in the redshifts of IEXs. This work provides new insights into understanding the tuning mechanism of tensile strain on IEXs and IAXs in two-dimensional (2D) HS, and paves a way to the development of flexible optoelectronic devices based on 2D materials.
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Affiliation(s)
- Anping Ge
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Xun Ge
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, People's Republic of China
| | - Liaoxin Sun
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Xinle Lu
- Key Laboratory of Polar Materials and Devices, Department of Electronics, East China Normal University, Shanghai, 200241, People's Republic of China
| | - Lei Ma
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, People's Republic of China
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, People's Republic of China
| | - Xinchao Zhao
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Bimu Yao
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Xin Zhang
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, People's Republic of China
- Department of Physics, Shanghai Normal University, Shanghai, 200234, People's Republic of China
| | - Tao Zhang
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Wenji Jing
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Xiaohao Zhou
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, People's Republic of China
| | - Xuechu Shen
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, People's Republic of China
| | - Wei Lu
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, 200083, People's Republic of China
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Kohler DD, Morrow DJ, Zhao Y, Scheeler JM, Jin S, Wright JC. Photoluminescence, Reflection Contrast, Raman, and Second Harmonic Generation Spectroscopies Spatially Resolve Strain, Alloying, Defects, and Electronic Characteristics of Lateral MX 2 Heterostructures. J Phys Chem Lett 2023; 14:9424-9432. [PMID: 37824438 DOI: 10.1021/acs.jpclett.3c02407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2023]
Abstract
Lateral heterostructures of two-dimensional (2D) transition metal dichalcogenides offer promise as platforms for a wide variety of applications from exotic physics to environmental control. Further development and study of these heterostructures require characterization methods that assess the quality of the heterostructures. Here, we extend current characterization strategies to create photoluminescence (PL), Raman, reflection contrast, and second harmonic generation (SHG) maps of individual monolayer core-shell WS2-MoS2 lateral heterostructures that were synthesized via water vapor assisted chemical vapor transport. Together, these methods provide the correlations required to resolve the effects of excitons, trions, lattice defects, strain, and alloying. The comparisons show substantial differences, especially in the regions near and at the narrow heterointerface. Comparisons between the different spectral maps show the importance of metal alloying for understanding the electronic and spatial structures of heterostructures. The results are compared to previous work on similar lateral heterostructures created by different methods.
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Affiliation(s)
- Daniel D Kohler
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Darien J Morrow
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Yuzhou Zhao
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Jason M Scheeler
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Song Jin
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - John C Wright
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
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5
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Zou J, Zhu R, Wang J, Meng H, Wang Z, Chen H, Weng YX. Coherent Phonon-Mediated Many-Body Interaction in Monolayer WSe 2. J Phys Chem Lett 2023; 14:4657-4665. [PMID: 37167104 DOI: 10.1021/acs.jpclett.3c00870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Due to the strong Coulomb interaction, the optical and electrical properties of two-dimensional transition metal dichalcogenides (TMDCs) are greatly determined by the emergence of many-body complexes such as excitons or trions. To fully realize the potential functionalities of these atomically thin materials, a comprehensive understanding of their many-body interaction mechanism is essential. Here, using the advanced femtosecond two-dimensional electronic spectroscopy technique combined with broadband transient absorption spectroscopy, a strong electron-exciton coupling effect in monolayer WSe2 following the ultrafast photoexcitation is revealed. We demonstrate that such many-body complexes can be generated effectively through the band-edge optical excitation, with a ∼1.5 ps stabilization process. The coherent optical phonon plays a dominant role in this electron-exciton interaction, and the coherence of the electron (exciton)-phonon coupling can last for ∼4.5 ps. This finding offers new insight into the formation mechanism of photoinduced many-body complexes in TMDCs.
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Affiliation(s)
- Jiading Zou
- Beijing National Laboratory for Condensed Matter Physics, Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ruidan Zhu
- Beijing National Laboratory for Condensed Matter Physics, Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jiayu Wang
- Beijing National Laboratory for Condensed Matter Physics, Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hanting Meng
- Beijing National Laboratory for Condensed Matter Physics, Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhuan Wang
- Beijing National Laboratory for Condensed Matter Physics, Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Hailong Chen
- Beijing National Laboratory for Condensed Matter Physics, Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Yu-Xiang Weng
- Beijing National Laboratory for Condensed Matter Physics, Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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6
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Kagkoura A, Stangel C, Arenal R, Tagmatarchis N. Molybdenum Diselenide and Tungsten Diselenide Interfacing Cobalt-Porphyrin for Electrocatalytic Hydrogen Evolution in Alkaline and Acidic Media. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 13:35. [PMID: 36615945 PMCID: PMC9824367 DOI: 10.3390/nano13010035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Revised: 12/14/2022] [Accepted: 12/15/2022] [Indexed: 06/17/2023]
Abstract
Easy and effective modification approaches for transition metal dichalcogenides are highly desired in order to make them active toward electrocatalysis. In this manner, we report functionalized molybdenum diselenide (MoSe2) and tungsten diselenide (WSe2) via metal-ligand coordination with pyridine rings for the subsequent covalent grafting of a cobalt-porphyrin. The new hybrid materials were tested towards an electrocatalytic hydrogen evolution reaction in both acidic and alkaline media and showed enhanced activity compared to intact MoSe2 and WSe2. Hybrids exhibited lower overpotential, easier reaction kinetics, higher conductivity, and excellent stability after 10,000 ongoing cycles in acidic and alkaline electrolytes compared to MoSe2 and WSe2. Markedly, MoSe2-based hybrid material showed the best performance and marked a significantly low onset potential of -0.17 V vs RHE for acidic hydrogen evolution reaction. All in all, the ease and fast modification route provides a versatile functionalization procedure, extendable to other transition metal dichalcogenides, and can open new pathways for the realization of functional nanomaterials suitable in electrocatalysis.
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Affiliation(s)
- Antonia Kagkoura
- Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constantinou Avenue, 11635 Athens, Greece
| | - Christina Stangel
- Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constantinou Avenue, 11635 Athens, Greece
| | - Raul Arenal
- Laboratorio de Microscopias Avanzadas (LMA), Universidad de Zaragoza, Mariano Esquillor s/n, 50018 Zaragoza, Spain
- Instituto de Nanociencia y Materiales de Aragon (INMA), CSIC-U. de Zaragoza, Calle Pedro Cerbuna 12, 50009 Zaragoza, Spain
- ARAID Foundation, 50018 Zaragoza, Spain
| | - Nikos Tagmatarchis
- Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constantinou Avenue, 11635 Athens, Greece
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7
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Pippia G, Van Hamme D, Martín-García B, Prato M, Moreels I. A colloidal route to semiconducting tungsten disulfide nanosheets with monolayer thickness. NANOSCALE 2022; 14:15859-15868. [PMID: 36259965 DOI: 10.1039/d2nr04307f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Transition metal dichalcogenides (TMDs) are a class of materials that have been extensively studied in the last decade, with molybdenum disulfide (MoS2) being the main protagonist. Typically, the interesting TMD properties, e.g. a direct band gap transition, or broken inversion symmetry, are only present in monolayer thick TMDs, and in the absence of strong lateral confinement, we require different materials or alloys thereof when we want to obtain TMDs with varying (direct) band gap energies. With this in mind, tungsten disulfide (WS2) is emerging as a direct competitor of MoS2 due to its similar properties but larger band gap energy. While several colloidal strategies have been reported for the synthesis of WS2, the synthesis of monolayer WS2 and detailed studies on the effect of synthesis parameters on the synthesis outcome have remained elusive. In this work we therefore focused on a colloidal synthesis method for monolayer WS2 using a design of experiment (DOE) approach. After optimization, we obtained nanosheets with a band gap transition consistent with the expected value for a monolayer. The thickness was further confirmed by Raman spectroscopy. While we could identify two temperature ranges where we could obtain a monolayer, sample characterization by XPS spectroscopy revealed the presence of different ratios of the metallic phase, with the sample synthesized at lower temperature displaying a lower concentration of the metallic phase.
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Affiliation(s)
- Gabriele Pippia
- Ghent University, Department of Chemistry, Krijgslaan 281, 9000 Gent, Belgium.
| | - Diem Van Hamme
- Ghent University, Department of Chemistry, Krijgslaan 281, 9000 Gent, Belgium.
| | - Beatriz Martín-García
- CIC nanoGUNE BRTA, Tolosa Hiribidea 76, 20018 Donostia-San Sebastián, Basque Country, Spain
| | - Mirko Prato
- Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
| | - Iwan Moreels
- Ghent University, Department of Chemistry, Krijgslaan 281, 9000 Gent, Belgium.
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8
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Liang X, Qin C, Qiao Z, Kang W, Yin H, Dong S, Li X, Wang S, Su X, Zhang G, Chen R, Hu J, Xiao L, Jia S. Optical interference effect in the hybrid quantum dots/two-dimensional materials: photoluminescence enhancement and modulation. OPTICS EXPRESS 2022; 30:26557-26569. [PMID: 36236844 DOI: 10.1364/oe.460054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 06/17/2022] [Indexed: 06/16/2023]
Abstract
The optical interference effect originating from the multiple reflections between the two-dimensional (2D) materials and the substrates has been used to dramatically enhance their Raman signal. However, this effect in the hybrid structures of colloidal quantum dots (QD) coupled to 2D materials is always overlooked. Here we theoretically prove that the photoluminescence (PL) intensities of the QD films in the QD-2D hybrid structures can be strongly enhanced and modulated by the optical interference effect between QD and 2D interfaces, breaking the inherent standpoint that PL intensities of the QD films are always prominently quenched in these hybrid structures. The theoretical predictions have been well confirmed by experimental measurements of PL properties of CdSe/ZnS and CdSeTe/ZnS QD on different 2D materials (such as WSe2, MoS2, and h-BN). PL intensities of these QD films have been periodically modulated from almost disappearing to strong enhancement (with the enhancement of about 6 times). The optical interference effect uncovered in this work enables a powerful method to manipulate the PL property of the QD films in the different QD-2D hybrid structures. These results can boost the optical performance of the QD-based electronic and optoelectronic devices in the hybrid QD-2D structures.
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9
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Miakota DI, Unocic RR, Bertoldo F, Ghimire G, Engberg S, Geohegan D, Thygesen KS, Canulescu S. A facile strategy for the growth of high-quality tungsten disulfide crystals mediated by oxygen-deficient oxide precursors. NANOSCALE 2022; 14:9485-9497. [PMID: 35748506 DOI: 10.1039/d2nr01863b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Chemical vapor deposition (CVD) has been established as a versatile route for the large-scale synthesis of transition metal dichalcogenides, such as tungsten disulfide (WS2). Yet, the precursor composition's role on the CVD process remains largely unknown and remains to be explored. Here, we employ Pulsed Laser Deposition (PLD) in a two-stage approach to tune the oxygen content in the tungsten oxide (WO3-x) precursors and demonstrate the presence of oxygen vacancies in the oxide films leads to a more facile conversion from WO3-x to WS2. Using a joint study based on ab initio density functional theory (DFT) calculations and experimental observations, we unravel that the oxygen vacancies in WO3-x can serve as niches through which sulfur atoms enter the lattice and facilitate an efficient conversion into WS2 crystals. By solely modulating the precursor stoichiometry, the photoluminescence emission of WS2 crystals can be significantly enhanced. Atomic resolution scanning transmission electron microscopy imaging (STEM) reveals that tungsten vacancies are the dominant intrinsic defects in mono- and bilayers WS2. Moreover, bi- and multilayer WS2 crystals derived from oxides with a high V0 content exhibit dominant AA'/AB or AA(A…) stacking orientations. The atomic resolution images reveal local strain buildup in bilayer WS2 due to competing effects of complex grain boundaries. Our study provides means to tune the precursor composition to control the lateral growth of TMDs while revealing insights into the different pathways for forming grain boundaries in bilayer WS2.
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Affiliation(s)
- Denys I Miakota
- Department of Photonics Engineering, Technical University of Denmark, DK-4000 Roskilde, Denmark.
| | - Raymond R Unocic
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Fabian Bertoldo
- CAMD and Center for Nanostructured Graphene (CNG), Department of Physics, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Ganesh Ghimire
- Department of Photonics Engineering, Technical University of Denmark, DK-4000 Roskilde, Denmark.
| | - Sara Engberg
- Department of Photonics Engineering, Technical University of Denmark, DK-4000 Roskilde, Denmark.
| | - David Geohegan
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Kristian S Thygesen
- CAMD and Center for Nanostructured Graphene (CNG), Department of Physics, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Stela Canulescu
- Department of Photonics Engineering, Technical University of Denmark, DK-4000 Roskilde, Denmark.
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10
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Zhu M, Zhang Z, Zhang T, Liu D, Zhang H, Zhang Z, Li Z, Cheng Y, Huang W. Exchange between Interlayer and Intralayer Exciton in WSe 2/WS 2 Heterostructure by Interlayer Coupling Engineering. NANO LETTERS 2022; 22:4528-4534. [PMID: 35588493 DOI: 10.1021/acs.nanolett.2c01353] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Because of type-II band alignment, interlayer exciton (IX) is found in a van der Waals (vdW) heterostructure (HS) formed by two monolayers of transition-metal dichalcogenides. Manipulation of IXs is of great importance for excitonic integrated devices. Here, we demonstrate that high pressure and tensile strain can be applied to enhance and reduce interlayer coupling of WSe2/WS2 HS, respectively. High pressure induces the transform of intralayer excitons to IX, while tensile strain leads to the transform of IXs to intralayer excitons. In addition, there is a direct-to-indirect band gap transition of WSe2/WS2 HS. The interlayer distance of WSe2/WS2 HS is reduced under high pressure, but it increased under uniaxial tensile strain from first-principles calculations. The calculated band structures explain well the transformation between interlayer and intralayer excitons of WSe2/WS2 HS. This work demonstrates the exchange of interlayer and intralayer excitons and paves the way to manipulate excitons of HS for excitonic applications.
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Affiliation(s)
- Mengqi Zhu
- Key Laboratory of Flexible Electronics & Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, 30 South Puzhu Road, Nanjing 211816, China
| | - Zhineng Zhang
- Key Laboratory of Flexible Electronics & Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, 30 South Puzhu Road, Nanjing 211816, China
| | - Tao Zhang
- Key Laboratory of Flexible Electronics & Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, 30 South Puzhu Road, Nanjing 211816, China
| | - Dongdong Liu
- Key Laboratory of Flexible Electronics & Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, 30 South Puzhu Road, Nanjing 211816, China
| | - Hao Zhang
- Key Laboratory of Flexible Electronics & Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, 30 South Puzhu Road, Nanjing 211816, China
| | - Zhenxiao Zhang
- Key Laboratory of Flexible Electronics & Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, 30 South Puzhu Road, Nanjing 211816, China
| | - Zhuolun Li
- Key Laboratory of Flexible Electronics & Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, 30 South Puzhu Road, Nanjing 211816, China
| | - Yingchun Cheng
- Key Laboratory of Flexible Electronics & Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, 30 South Puzhu Road, Nanjing 211816, China
| | - Wei Huang
- Key Laboratory of Flexible Electronics & Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, 30 South Puzhu Road, Nanjing 211816, China
- Frontiers Science Center for Flexible Electronics, Xi'an Institute of Flexible Electronics and Xi'an Institute of Biomedical Materials & Engineering, Northwestern Polytechnical University, 127 West Youyi Road, Xi'an 710072, China
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11
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Pimenta Martins LG, Carvalho BR, Occhialini CA, Neme NP, Park JH, Song Q, Venezuela P, Mazzoni MSC, Matos MJS, Kong J, Comin R. Electronic Band Tuning and Multivalley Raman Scattering in Monolayer Transition Metal Dichalcogenides at High Pressures. ACS NANO 2022; 16:8064-8075. [PMID: 35466673 DOI: 10.1021/acsnano.2c01065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Transition metal dichalcogenides (TMDs) possess spin-valley locking and spin-split K/K' valleys, which have led to many fascinating physical phenomena. However, the electronic structure of TMDs also exhibits other conduction band minima with similar properties, the Q/Q' valleys. The intervalley K-Q scattering enables interesting physical phenomena, including multivalley superconductivity, but those effects are typically hindered in monolayer TMDs due to the large K-Q energy difference (ΔEKQ). To unlock elusive multivalley phenomena in monolayer TMDs, it is desirable to reduce ΔEKQ, while being able to sensitively probe the valley shifts and the multivalley scattering processes. Here, we use high pressure to tune the electronic properties of monolayer MoS2 and WSe2 and probe K-Q crossing and multivalley scattering via double-resonance Raman (DRR) scattering. In both systems, we observed a pressure-induced enhancement of the double-resonance LA and 2LA Raman bands, which can be attributed to a band gap opening and ΔEKQ decrease. First-principles calculations and photoluminescence measurements corroborate this scenario. In our analysis, we also addressed the multivalley nature of the DRR bands for WSe2. Our work establishes the DRR 2LA and LA bands as sensitive probes of strain-induced modifications to the electronic structure of TMDs. Conversely, their intensity could potentially be used to monitor the presence of compressive or tensile strain in TMDs. Furthermore, the ability to probe K-K' and K-Q scattering as a function of strain shall advance our understanding of different multivalley phenomena in TMDs such as superconductivity, valley coherence, and valley transport.
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Affiliation(s)
- Luiz G Pimenta Martins
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Bruno R Carvalho
- Departamento de Física, Universidade Federal do Rio Grande do Norte, Natal, Rio Grande do Norte 59078-970, Brazil
| | - Connor A Occhialini
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Natália P Neme
- Zernike Institute for Advanced Materials and Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Ji-Hoon Park
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Qian Song
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Pedro Venezuela
- Instituto de Física, Universidade Federal Fluminense, Niterói, Rio de Janeiro 24210-346, Brazil
| | - Mário S C Mazzoni
- Departamento de Física, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais 31270-901, Brazil
| | - Matheus J S Matos
- Departamento de Física, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais 35400-000, Brazil
| | - Jing Kong
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Riccardo Comin
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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12
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Londoño-Calderon A, Dhall R, Ophus C, Schneider M, Wang Y, Dervishi E, Kang HS, Lee CH, Yoo J, Pettes MT. Visualizing Grain Statistics in MOCVD WSe 2 through Four-Dimensional Scanning Transmission Electron Microscopy. NANO LETTERS 2022; 22:2578-2585. [PMID: 35143727 DOI: 10.1021/acs.nanolett.1c04315] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Using four-dimensional scanning transmission electron microscopy, we demonstrate a method to visualize grains and grain boundaries in WSe2 grown by metal organic chemical vapor deposition (MOCVD) directly onto silicon dioxide. Despite the chemical purity and uniform thickness and texture of the MOCVD-grown WSe2, we observe a high density of small grains that corresponds with the overall selenium deficiency we measure through ion beam analysis. Moreover, reconstruction of grain information permits the creation of orientation maps that demonstrate the nucleation mechanism for new layers-triangular domains with the same orientation as the layer underneath induces a tensile strain increasing the lattice parameter at these sites.
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Affiliation(s)
- Alejandra Londoño-Calderon
- Center for Integrated Nanotechnologies (CINT), Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Rohan Dhall
- National Center for Electron Microscopy (NCEM), Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Colin Ophus
- National Center for Electron Microscopy (NCEM), Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Matthew Schneider
- Materials Science in Radiation and Dynamics Extremes (MST-8), Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Yongqiang Wang
- Center for Integrated Nanotechnologies (CINT), Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
- Materials Science in Radiation and Dynamics Extremes (MST-8), Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Enkeleda Dervishi
- Electrochemistry and Corrosion Team, Sigma Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Hee Seong Kang
- KU-KIST Graduate School of Converging Science and Technology & Department of Integrative Energy Engineering, Korea University, Seoul, 02841, Republic of Korea
| | - Chul-Ho Lee
- KU-KIST Graduate School of Converging Science and Technology & Department of Integrative Energy Engineering, Korea University, Seoul, 02841, Republic of Korea
- Advanced Materials Research Division, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
| | - Jinkyoung Yoo
- Center for Integrated Nanotechnologies (CINT), Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Michael T Pettes
- Center for Integrated Nanotechnologies (CINT), Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
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13
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Kim UJ, Nam SH, Seo J, Yang M, Fu Q, Liu Z, Son H, Lee M, Hahm MG. Visualizing Line Defects in non-van der Waals Bi 2O 2Se Using Raman Spectroscopy. ACS NANO 2022; 16:3637-3646. [PMID: 35166540 DOI: 10.1021/acsnano.1c06598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Atomic-layered materials, such as high-quality bismuth oxychalcogenides, which are composed of oppositely charged alternate layers grown using chemical vapor deposition, have attracted considerable attention. Their physical properties are well-suited for high-speed, low-power-consumption optoelectronic devices, and the rapid determination of their crystallographic characteristics is crucial for scalability and integration. In this study, we introduce how the crystallographic structure and quality of such materials can be projected through Raman spectroscopy analysis. Frequency modes at ∼55, ∼78, ∼360, and ∼434 cm-1 were detected, bearing out theoretical calculations from the literature. The low-frequency modes positioned at 55 and 78 cm-1 were activated by structural defects, such as grain boundaries and O-rich edges in the Bi2O2Se crystals, accompanied by sensitivity to the excitation energy. Furthermore, the line defects at ∼55 cm-1 exhibited a strong 2-fold polarization dependence, similar to graphene/graphite edges. Our results can help illuminate the mechanism for activating the Raman-active mode from the infrared active mode by defects, as well as the electronic structures of these two-dimensional layered materials. We also suggest that the nanoscale width line defects in Bi2O2Se can be visualized using Raman spectroscopy.
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Affiliation(s)
- Un Jeong Kim
- Advanced Sensor Laboratory, Samsung Advanced Institute of Technology, Suwon, Gyeonggi-do 16419, Republic of Korea
| | - Seung Hyun Nam
- Department of Materials Science and Engineering, Inha University, 100 Inha-ro, Michuhol-gu, Incheon, 22212, Republic of Korea
| | - Juyeon Seo
- Department of Materials Science and Engineering, Inha University, 100 Inha-ro, Michuhol-gu, Incheon, 22212, Republic of Korea
| | - Mino Yang
- Korea Basic Science Institute Seoul, Seoul, 02841, Republic of Korea
| | - Qundong Fu
- School of Materials Science & Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Zheng Liu
- School of Materials Science & Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Hyungbin Son
- School of Integrative Engineering, Chung-Ang University, Seoul, 06974, Republic of Korea
| | - Moonsang Lee
- Department of Materials Science and Engineering, Inha University, 100 Inha-ro, Michuhol-gu, Incheon, 22212, Republic of Korea
| | - Myung Gwan Hahm
- Department of Materials Science and Engineering, Inha University, 100 Inha-ro, Michuhol-gu, Incheon, 22212, Republic of Korea
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14
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Sun X, Qin F, Huang J, Zhou L, Li Z, Bi X, Ao L, Duan S, Cheng F, Qiu C, Lu Y, Lu H, Gou H, Yuan H. Emergent Fabry-Pérot Interference for Light-Matter Interaction in van der Waals WS 2/SiP 2 Heterostructures. ACS APPLIED MATERIALS & INTERFACES 2022; 14:7464-7470. [PMID: 35099944 DOI: 10.1021/acsami.1c22768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Fabry-Pérot interference plays an important role in modulating the spectral intensity of optical response originating from light-matter interactions. Examples of such interference occurring in the substrate as the resonating cavity have been demonstrated and probed by two-dimensional layered materials. Similarly, the Fabry-Pérot interference can occur and modulate the optical response in the heterostructure; however, this remains elusive. Herein, we observe the Fabry-Pérot interference on photoluminescence (PL) and Raman spectra in monolayer WS2/SiP2 heterostructures by varying the thickness of bottom SiP2 from 2 to 193 nm, which serves as the Fabry-Pérot cavity. Both the intensities of the PL spectra and the E2g1 Raman mode of WS2/SiP2 heterostructures first decrease to almost zero while displaying an interference increase at a SiP2 thickness of 75 nm. Our findings clearly demonstrate the Fabry-Pérot interference in the optical response of heterostructures, providing crucial information to optimize the optical response and paving the way toward photodetector applications.
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Affiliation(s)
- Xiaojun Sun
- College of Engineering and Applied Sciences, National Laboratory of Solid State Microstructures and Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210000, China
| | - Feng Qin
- College of Engineering and Applied Sciences, National Laboratory of Solid State Microstructures and Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210000, China
| | - Junwei Huang
- College of Engineering and Applied Sciences, National Laboratory of Solid State Microstructures and Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210000, China
| | - Ling Zhou
- College of Engineering and Applied Sciences, National Laboratory of Solid State Microstructures and Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210000, China
| | - Zeya Li
- College of Engineering and Applied Sciences, National Laboratory of Solid State Microstructures and Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210000, China
| | - Xiangyu Bi
- College of Engineering and Applied Sciences, National Laboratory of Solid State Microstructures and Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210000, China
| | - Lingyi Ao
- College of Engineering and Applied Sciences, National Laboratory of Solid State Microstructures and Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210000, China
| | - Siyu Duan
- College of Engineering and Applied Sciences, National Laboratory of Solid State Microstructures and Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210000, China
| | - Fanghua Cheng
- College of Engineering and Applied Sciences, National Laboratory of Solid State Microstructures and Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210000, China
| | - Caiyu Qiu
- College of Engineering and Applied Sciences, National Laboratory of Solid State Microstructures and Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210000, China
| | - Yangfan Lu
- College of Materials Science and Engineering, National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400030, China
| | - Hong Lu
- College of Engineering and Applied Sciences, National Laboratory of Solid State Microstructures and Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210000, China
| | - Huiyang Gou
- Center for High Pressure Science and Technology Advanced Research, Beijing 100094, China
| | - Hongtao Yuan
- College of Engineering and Applied Sciences, National Laboratory of Solid State Microstructures and Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210000, China
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15
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Chen P, Pan J, Gao W, Wan B, Kong X, Cheng Y, Liu K, Du S, Ji W, Pan C, Wang ZL. Anisotropic Carrier Mobility from 2H WSe 2. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2108615. [PMID: 34859917 DOI: 10.1002/adma.202108615] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 12/01/2021] [Indexed: 06/13/2023]
Abstract
Transition metal dichalcogenides (TMDCs) with 2H phase are expected to be building blocks in next-generation electronics; however, they suffer from electrical anisotropy, which is the basics for multi-terminal artificial synaptic devices, digital inverters, and anisotropic memtransistors, which are highly desired in neuromorphic computing. Herein, the anisotropic carrier mobility from 2H WSe2 is reported, where the anisotropic degree of carrier mobility spans from 0.16 to 0.95 for various WSe2 field-effect transistors under a gate voltage of -60 V. Phonon scattering, impurity ions scattering, and defect scattering are excluded for anisotropic mobility. An intrinsic screening layer is proposed and confirmed by Z-contrast scanning transmission electron microscopy (STEM) imaging to respond to the electrical anisotropy. Seven types of intrinsic screening layers are created and calculated by density functional theory to evaluate the modulated electronic structures, effective masses, and scattering intensities, resulting in anisotropic mobility. The discovery of anisotropic carrier mobility from 2H WSe2 provides a degree of freedom for adjusting the physical properties of 2H TMDCs and fertile ground for exploring and integrating TMDC electronic transistors with better performance along the direction of high mobility.
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Affiliation(s)
- Ping Chen
- Center on Nanoenergy Research, School of Physical Science and Technology, Guangxi University, Nanning, 530004, China
- CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Micro-nano Energy and Sensor, Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing, 100083, China
| | - Jinbo Pan
- Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, China
| | - Wenchao Gao
- CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Micro-nano Energy and Sensor, Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing, 100083, China
| | - Bensong Wan
- CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Micro-nano Energy and Sensor, Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing, 100083, China
| | - Xianghua Kong
- Centre for the Physics of Materials and Department of Physics, McGill University, Montreal, QC, H3A 2T8, Canada
| | - Yang Cheng
- State Key Laboratory for Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, School of Physics, Peking University, Beijing, 100871, China
| | - Kaihui Liu
- State Key Laboratory for Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, School of Physics, Peking University, Beijing, 100871, China
| | - Shixuan Du
- Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, China
| | - Wei Ji
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-Nano Devices, Renmin University of China, Beijing, 100872, China
| | - Caofeng Pan
- Center on Nanoenergy Research, School of Physical Science and Technology, Guangxi University, Nanning, 530004, China
- CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Micro-nano Energy and Sensor, Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing, 100083, China
- College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China
- School of Nanoscience and Technology, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhong Lin Wang
- Center on Nanoenergy Research, School of Physical Science and Technology, Guangxi University, Nanning, 530004, China
- CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Micro-nano Energy and Sensor, Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing, 100083, China
- School of Nanoscience and Technology, University of Chinese Academy of Sciences, Beijing, 100049, China
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA, 30332-0245, USA
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16
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Pimenta MA, Resende GC, Ribeiro HB, Carvalho BR. Polarized Raman spectroscopy in low-symmetry 2D materials: angle-resolved experiments and complex number tensor elements. Phys Chem Chem Phys 2021; 23:27103-27123. [PMID: 34859800 DOI: 10.1039/d1cp03626b] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
In this perspective review, we discuss the power of polarized Raman spectroscopy to study optically anisotropic 2D materials, belonging to the orthorhombic, monoclinic and triclinic crystal families. We start by showing that the polarization dependence of the peak intensities is described by the Raman tensor that is unique for each phonon mode, and then we discuss how to determine the tensor elements from the angle-resolved polarized measurements by analyzing the intensities in both the parallel- and cross-polarized scattering configurations. We present specific examples of orthorhombic black phosphorus and monoclinic 1T'-MoTe2, where the Raman tensors have null elements and their principal axes coincide with the crystallographic ones, followed by a discussion on the results for triclinic ReS2 and ReSe2, where the axes of the Raman tensor do not coincide with the crystallographic axes and all elements are non-zero. We show that the Raman tensor elements are, in general, given by complex numbers and that phase differences between tensor elements are needed to describe the experimental results. We discuss the dependence of the Raman tensors on the excitation laser energy and thickness of the sample within the framework of the quantum model for the Raman intensities. We show that the wavevector dependence of the electron-phonon interaction is essential for explaining the distinct Raman tensor for each phonon mode. Finally, we close with our concluding remarks and perspectives to be explored using angle-resolved polarized Raman spectroscopy in optically anisotropic 2D materials.
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Affiliation(s)
- Marcos A Pimenta
- Departamento de Física, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais 30123-970, Brazil.
| | - Geovani C Resende
- Departamento de Física, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais 30123-970, Brazil.
| | - Henrique B Ribeiro
- Department of Applied Physics, Stanford University, Stanford, California, 94305, USA
| | - Bruno R Carvalho
- Departamento de Física, Universidade Federal do Rio Grande do Norte, Natal, Rio Grande do Norte 59078-970, Brazil.
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17
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Komen I, van Heijst SE, Conesa-Boj S, Kuipers L. Morphology-induced spectral modification of self-assembled WS 2 pyramids. NANOSCALE ADVANCES 2021; 3:6427-6437. [PMID: 34913025 PMCID: PMC8577507 DOI: 10.1039/d1na00531f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 09/21/2021] [Indexed: 06/14/2023]
Abstract
Due to their intriguing optical properties, including stable and chiral excitons, two-dimensional transition metal dichalcogenides (2D-TMDs) hold the promise of applications in nanophotonics. Chemical vapor deposition (CVD) techniques offer a platform to fabricate and design nanostructures with diverse geometries. However, the more exotic the grown nanogeometry, the less is known about its optical response. WS2 nanostructures with geometries ranging from monolayers to hollow pyramids have been created. The hollow pyramids exhibit a strongly reduced photoluminescence with respect to horizontally layered tungsten disulphide, facilitating the study of their clear Raman signal in more detail. Excited resonantly, the hollow pyramids exhibit a great number of higher-order phononic resonances. In contrast to monolayers, the spectral features of the optical response of the pyramids are position dependent. Differences in peak intensity, peak ratio and spectral peak positions reveal local variations in the atomic arrangement of the hollow pyramid crater and sides. The position-dependent optical response of hollow WS2 pyramids is characterized and attributed to growth-induced nanogeometry. Thereby the first steps are taken towards producing tunable nanophotonic devices with applications ranging from opto-electronics to non-linear optics.
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Affiliation(s)
- Irina Komen
- Kavli Institute of Nanoscience, Department of Quantum Nanoscience, Delft University of Technology The Netherlands
| | - Sabrya E van Heijst
- Kavli Institute of Nanoscience, Department of Quantum Nanoscience, Delft University of Technology The Netherlands
| | - Sonia Conesa-Boj
- Kavli Institute of Nanoscience, Department of Quantum Nanoscience, Delft University of Technology The Netherlands
| | - L Kuipers
- Kavli Institute of Nanoscience, Department of Quantum Nanoscience, Delft University of Technology The Netherlands
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18
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Xu X, Hu X, Li X, Yang M, Liu J, Guo Q, Wang Y, Liang B. Abnormal temperature-dependent photoluminescence characteristics of ReS 2nanowalls. NANOTECHNOLOGY 2021; 32:505723. [PMID: 34587588 DOI: 10.1088/1361-6528/ac2b6e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 09/28/2021] [Indexed: 06/13/2023]
Abstract
Two samples with [001] orientated rhenium disulfide (ReS2) nanowalls (NWs) grown above and in front of precursor (NH4ReO4) by chemical vapor deposition were investigated. The temperature-dependent photoluminescence (PL) indicated that the PL peak exhibited linear blue-shift at a rate of ∼0.24 meV K-1with increasing the temperature from 10 to 300 K, while the linewidth monotonically increased due to the exciton-phonon interaction. This abnormal blue-shift of PL emission energy, which is explained by a competition between the band gap shrinkage and the energy level degeneracy with respect to the increase of temperature and lattice constant, enables ReS2NWs to possess great potential for development of thermal sensors. In addition, exciton localization effect in the ReS2NWs from abundant edges and weak interlayer interaction was also observed to be related to the height and density of ReS2NWs. These results not only enrich the understanding for exciton dynamics in ReS2NWs, but also help to exploit ReS2NWs for device applications.
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Affiliation(s)
- Xuejun Xu
- Hebei Key Laboratory of Optic-Electronic Information and Materials, College of Physics Science & Technology, Hebei University, Baoding 071002, People's Republic of China
| | - Xiaowen Hu
- Hebei Key Laboratory of Optic-Electronic Information and Materials, College of Physics Science & Technology, Hebei University, Baoding 071002, People's Republic of China
| | - Xiaoli Li
- Hebei Key Laboratory of Optic-Electronic Information and Materials, College of Physics Science & Technology, Hebei University, Baoding 071002, People's Republic of China
| | - Mingming Yang
- Hebei Key Laboratory of Optic-Electronic Information and Materials, College of Physics Science & Technology, Hebei University, Baoding 071002, People's Republic of China
| | - Jingtao Liu
- Hebei Key Laboratory of Optic-Electronic Information and Materials, College of Physics Science & Technology, Hebei University, Baoding 071002, People's Republic of China
| | - Qinglin Guo
- Hebei Key Laboratory of Optic-Electronic Information and Materials, College of Physics Science & Technology, Hebei University, Baoding 071002, People's Republic of China
| | - Ying Wang
- Hebei Key Laboratory of Optic-Electronic Information and Materials, College of Physics Science & Technology, Hebei University, Baoding 071002, People's Republic of China
| | - Baolai Liang
- Hebei Key Laboratory of Optic-Electronic Information and Materials, College of Physics Science & Technology, Hebei University, Baoding 071002, People's Republic of China
- California Nano Systems Institute, University of California, Los Angeles, CA 90095, United States of America
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19
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Wang W, Sui N, Kang Z, Zhou Q, Li L, Chi X, Zhang H, He X, Zhao B, Wang Y. Cooling and diffusion characteristics of a hot carrier in the monolayer WS 2. OPTICS EXPRESS 2021; 29:7736-7745. [PMID: 33726269 DOI: 10.1364/oe.419345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 02/12/2021] [Indexed: 06/12/2023]
Abstract
The characteristics of a hot carrier distributed in the C excitonic state of the monolayer WS2 is investigated by exploiting the transient absorption (TA) spectroscopy. The hot carrier cooling lifetime gradually prolongs from 0.58 ps to 2.68 ps with the absorbed photon flux owing to the hot phonon bottleneck effect, as the excitation photon energy is 2.03 eV. Meanwhile, the normalized TA spectra shows that the spectral feature of hot carriers is different from that of normal carriers. Based on the modified Lennard-Jones model, the average distance among hot carriers can be estimated according to the peak shift of TA spectra and the diffusion velocity can also be calculated simultaneously. The hot carrier limits the diffusion of the photo-generated carrier at the initial several picoseconds. These results help people to elucidate the hot carrier dynamics in 2D TMDCs and give guidance on the designing and optimizing the TMDC-based electronic devices of high performance.
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20
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Fu S, du Fossé I, Jia X, Xu J, Yu X, Zhang H, Zheng W, Krasel S, Chen Z, Wang ZM, Tielrooij KJ, Bonn M, Houtepen AJ, Wang HI. Long-lived charge separation following pump-wavelength-dependent ultrafast charge transfer in graphene/WS 2 heterostructures. SCIENCE ADVANCES 2021; 7:7/9/eabd9061. [PMID: 33637529 PMCID: PMC7909886 DOI: 10.1126/sciadv.abd9061] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 01/12/2021] [Indexed: 05/27/2023]
Abstract
Van der Waals heterostructures consisting of graphene and transition metal dichalcogenides have shown great promise for optoelectronic applications. However, an in-depth understanding of the critical processes for device operation, namely, interfacial charge transfer (CT) and recombination, has so far remained elusive. Here, we investigate these processes in graphene-WS2 heterostructures by complementarily probing the ultrafast terahertz photoconductivity in graphene and the transient absorption dynamics in WS2 following photoexcitation. We observe that separated charges in the heterostructure following CT live extremely long: beyond 1 ns, in contrast to ~1 ps charge separation reported in previous studies. This leads to efficient photogating of graphene. Furthermore, for the CT process across graphene-WS2 interfaces, we find that it occurs via photo-thermionic emission for sub-A-exciton excitations and direct hole transfer from WS2 to the valence band of graphene for above-A-exciton excitations. These findings provide insights to further optimize the performance of optoelectronic devices, in particular photodetection.
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Affiliation(s)
- Shuai Fu
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
| | - Indy du Fossé
- Optoelectronic Materials Section, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, Netherlands
| | - Xiaoyu Jia
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
| | - Jingyin Xu
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, P. R. China
| | - Xiaoqing Yu
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
| | - Heng Zhang
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
| | - Wenhao Zheng
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
| | - Sven Krasel
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
| | - Zongping Chen
- School of Materials Science and Engineering, Zhejiang University, Zheda Road 38, Hangzhou 310027, China
| | - Zhiming M Wang
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, P. R. China
| | - Klaas-Jan Tielrooij
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), BIST and CSIC, Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Mischa Bonn
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
| | - Arjan J Houtepen
- Optoelectronic Materials Section, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, Netherlands
| | - Hai I Wang
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany.
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21
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Darlington TP, Krayev A, Venkatesh V, Saxena R, Kysar JW, Borys NJ, Jariwala D, Schuck PJ. Facile and quantitative estimation of strain in nanobubbles with arbitrary symmetry in 2D semiconductors verified using hyperspectral nano-optical imaging. J Chem Phys 2020; 153:024702. [DOI: 10.1063/5.0012817] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Affiliation(s)
- Thomas P. Darlington
- Department of Physics, University of California, Berkeley, California 94720, USA
| | | | - Vishal Venkatesh
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Ravindra Saxena
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Jeffrey W. Kysar
- Department of Mechanical Engineering, Columbia University, New York, New York 10027, USA
| | - Nicholas J. Borys
- Department of Physics, Montana State University, Bozeman, Montana 59717, USA
| | - Deep Jariwala
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - P. James Schuck
- Department of Mechanical Engineering, Columbia University, New York, New York 10027, USA
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22
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Taghizadeh A, Leffers U, Pedersen TG, Thygesen KS. A library of ab initio Raman spectra for automated identification of 2D materials. Nat Commun 2020; 11:3011. [PMID: 32541789 PMCID: PMC7296020 DOI: 10.1038/s41467-020-16529-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 05/06/2020] [Indexed: 11/09/2022] Open
Abstract
Raman spectroscopy is frequently used to identify composition, structure and layer thickness of 2D materials. Here, we describe an efficient first-principles workflow for calculating resonant first-order Raman spectra of solids within third-order perturbation theory employing a localized atomic orbital basis set. The method is used to obtain the Raman spectra of 733 different monolayers selected from the Computational 2D Materials Database (C2DB). We benchmark the computational scheme against available experimental data for 15 known monolayers. Furthermore, we propose an automatic procedure for identifying a material based on an input experimental Raman spectrum and apply it to the cases of MoS2 (H-phase) and WTe2 (T[Formula: see text]-phase). The Raman spectra of all materials at different excitation frequencies and polarization configurations are freely available from the C2DB. Our comprehensive and easily accessible library of ab initio Raman spectra should be valuable for both theoreticians and experimentalists in the field of 2D materials.
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Affiliation(s)
- Alireza Taghizadeh
- Department of Materials and Production, Aalborg University, Aalborg, Øst, 9220, Denmark.
- Center for Nanostructured Graphene (CNG), Aalborg, Øst, 9220, Denmark.
- Computational Atomic-scale Materials Design (CAMD), Department of Physics, Technical University of Denmark (DTU), Lyngby, 2800 Kgs, Denmark.
| | - Ulrik Leffers
- Computational Atomic-scale Materials Design (CAMD), Department of Physics, Technical University of Denmark (DTU), Lyngby, 2800 Kgs, Denmark
| | - Thomas G Pedersen
- Department of Materials and Production, Aalborg University, Aalborg, Øst, 9220, Denmark
- Center for Nanostructured Graphene (CNG), Aalborg, Øst, 9220, Denmark
| | - Kristian S Thygesen
- Computational Atomic-scale Materials Design (CAMD), Department of Physics, Technical University of Denmark (DTU), Lyngby, 2800 Kgs, Denmark
- Center for Nanostructured Graphene (CNG), Technical University of Denmark (DTU), Lyngby, 2800 Kgs, Denmark
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23
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Hou J, Ke C, Chen J, Sun B, Xia Y, Li X, Chen T, Wu Y, Wu Z, Kang J. Reduced Turn-On Voltage and Boosted Mobility in Monolayer WS 2 Transistors by Mild Ar + Plasma Treatment. ACS APPLIED MATERIALS & INTERFACES 2020; 12:19635-19642. [PMID: 32255332 DOI: 10.1021/acsami.0c00001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Monolayer two-dimensional transition-metal dichalcogenides, such as tungsten disulfide (WS2), are regarded as promising candidates for optoelectronic and electronic applications. Although theoretical calculations have predicted outstanding electronic properties of WS2, the performance of WS2-based electronic devices is still limited by the relatively high Schottky barrier and low carrier mobility. In this work, low-energy argon (Ar+) plasma treatment was used as a nondestructive preconditioning technique to tailor the electrical properties of the WS2 monolayer grown by chemical vapor deposition. Photoluminescence and Raman spectroscopy were used to monitor the modified optical properties of WS2 with increasing plasma treatment time. An improved electrical conductivity was observed after a short-time plasma treatment. The physical mechanism was further revealed by a comparative study between top-electrode and bottom-electrode devices and simulation based on the density functional theory. It is concluded that mild Ar+ plasma treatment can effectively lower the Schottky barrier height and the effective mass of carriers, which reduces the turn-on voltage and enhances the mobility, respectively. However, if the processing time is too long, the WS2 lattice structure will be destroyed. This work has provided an effective method for manipulating the Schottky barrier and mobility of monolayer WS2 transistors and paves the way for developing high-performance electronic devices based on 2D semiconductors.
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Affiliation(s)
- Junfeng Hou
- Department of Physics, OSED, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Jiujiang Research Institute, Xiamen University, Xiamen 361005, P. R. China
| | - Congming Ke
- Department of Physics, OSED, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Jiujiang Research Institute, Xiamen University, Xiamen 361005, P. R. China
| | - Jiajun Chen
- Department of Physics, OSED, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Jiujiang Research Institute, Xiamen University, Xiamen 361005, P. R. China
| | - Baofan Sun
- Department of Physics, OSED, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Jiujiang Research Institute, Xiamen University, Xiamen 361005, P. R. China
| | - Yuanzheng Xia
- Department of Physics, OSED, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Jiujiang Research Institute, Xiamen University, Xiamen 361005, P. R. China
| | - Xu Li
- Department of Physics, OSED, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Jiujiang Research Institute, Xiamen University, Xiamen 361005, P. R. China
| | - Ting Chen
- Department of Physics, OSED, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Jiujiang Research Institute, Xiamen University, Xiamen 361005, P. R. China
| | - Yaping Wu
- Department of Physics, OSED, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Jiujiang Research Institute, Xiamen University, Xiamen 361005, P. R. China
| | - Zhiming Wu
- Department of Physics, OSED, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Jiujiang Research Institute, Xiamen University, Xiamen 361005, P. R. China
| | - Junyong Kang
- Department of Physics, OSED, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Jiujiang Research Institute, Xiamen University, Xiamen 361005, P. R. China
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24
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Ahmed S, Ding X, Murmu PP, Bao N, Liu R, Kennedy J, Wang L, Ding J, Wu T, Vinu A, Yi J. High Coercivity and Magnetization in WSe 2 by Codoping Co and Nb. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e1903173. [PMID: 31441228 DOI: 10.1002/smll.201903173] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 07/22/2019] [Indexed: 06/10/2023]
Abstract
Introducing ferromagnetism in transition metal dichalcogenides has attracted lots of attention due to the possible applications in spintronics devices. Generally, single magnetic element doping is used to introduce magnetism. However, mostly, weak ferromagnetism is observed. In this work, codoping of two kinds of transition metals (Nb and Co) into WSe2 is used to study its magnetic properties. In detail, single crystal WSe2 is codoped with 4 at% Co and various concentrations of Nb by employing the physical ion implantation method. Raman, X-ray diffraction and X-ray photoelectron spectroscopy results reveal the effective substitutional doping of implanted elements (Co and Nb). Magnetic measurements illustrate that both un-doped and 4 at% Co doped WSe2 show weak ferromagnetism whereas magnetization is strongly enhanced when Co and Nb are codoped into WSe2 . The magnetization is comparable with a ferromagnet, which may be attributed to Co, Nb doping and defects. In addition, a large coercivity of ≈1.2 kOe is observed in the 1 at% Nb-4 at% Co codoped WSe2 sample, which may be ascribed to the combined effect of doping-induced stress, defect-dictated pinning and anisotropy of NbSe bond owing to the charge transfer between Nb and Se ions.
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Affiliation(s)
- Sohail Ahmed
- School of Materials Science and Engineering, UNSW, Sydney, NSW, 2052, Australia
| | - Xiang Ding
- School of Materials Science and Engineering, UNSW, Sydney, NSW, 2052, Australia
| | - Peter P Murmu
- National Isotope Centre, GNS Science, P.O. Box 31312, Lower Hutt, 5010, New Zealand
| | - Nina Bao
- Department of Materials Science and Engineering, National University of Singapore, Singapore, 119260, Singapore
| | - Rong Liu
- SIMS Facility, Office of the Deputy-Vice-Chancellor (R&D), Western Sydney University, Penrith, NSW, 2751, Australia
| | - John Kennedy
- National Isotope Centre, GNS Science, P.O. Box 31312, Lower Hutt, 5010, New Zealand
| | - Lan Wang
- School of Science, RMIT University, Melbourne, Victoria, 3001, Australia
| | - Jun Ding
- Department of Materials Science and Engineering, National University of Singapore, Singapore, 119260, Singapore
| | - Tom Wu
- School of Materials Science and Engineering, UNSW, Sydney, NSW, 2052, Australia
| | - Ajayan Vinu
- Global Innovative Centre for Advanced Nanomaterials, School of Engineering, The University of Newcastle, Callaghan, NSW, 2308, Australia
| | - Jiabao Yi
- Global Innovative Centre for Advanced Nanomaterials, School of Engineering, The University of Newcastle, Callaghan, NSW, 2308, Australia
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25
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McCreary A, Simpson JR, Mai TT, McMichael RD, Douglas JE, Butch N, Dennis C, Aguilar RV, Walker ARH. Quasi-Two-Dimensional Magnon Identification in Antiferromagnetic FePS 3via Magneto-Raman Spectroscopy. PHYSICAL REVIEW. B 2020; 101:10.1103/PhysRevB.101.064416. [PMID: 38616972 PMCID: PMC11015466 DOI: 10.1103/physrevb.101.064416] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Recently it was discovered that van der Waals-bonded magnetic materials retain long range magnetic ordering down to a single layer, opening many avenues in fundamental physics and potential applications of these fascinating materials. One such material is FePS3, a large spin (S=2) Mott insulator where the Fe atoms form a honeycomb lattice. In the bulk, FePS3 has been shown to be a quasi-two-dimensional-Ising antiferromagnet, with additional features in the Raman spectra emerging below the Néel temperature (T N ) of approximately 120 K. Using magneto-Raman spectroscopy as an optical probe of magnetic structure, we show that one of these Raman-active modes in the magnetically ordered state is actually a magnon with a frequency of ≈3.7 THz (122 cm-1). Contrary to previous work, which interpreted this feature as a phonon, our Raman data shows the expected frequency shifting and splitting of the magnon as a function of temperature and magnetic field, respectively, where we determine the g-factor to be ≈2. In addition, the symmetry behavior of the magnon is studied by polarization-dependent Raman spectroscopy and explained using the magnetic point group of FePS3.
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Affiliation(s)
- Amber McCreary
- Nanoscale Device Characterization Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Jeffrey R. Simpson
- Nanoscale Device Characterization Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
- Department of Physics, Astronomy, and Geosciences, Towson University, Towson, MD 21252, USA
| | - Thuc T. Mai
- Nanoscale Device Characterization Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
- Department of Physics, The Ohio State University, Columbus, OH 43210, USA
| | - Robert D. McMichael
- Nanoscale Device Characterization Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Jason E. Douglas
- Materials Science and Engineering Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Nicholas Butch
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Cindi Dennis
- Materials Science and Engineering Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | | | - Angela R. Hight Walker
- Nanoscale Device Characterization Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
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26
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Yang C, Gao Y, Qin C, Liang X, Han S, Zhang G, Chen R, Hu J, Xiao L, Jia S. All-Optical Reversible Manipulation of Exciton and Trion Emissions in Monolayer WS 2. NANOMATERIALS 2019; 10:nano10010023. [PMID: 31861767 PMCID: PMC7023460 DOI: 10.3390/nano10010023] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 12/17/2019] [Accepted: 12/18/2019] [Indexed: 01/20/2023]
Abstract
Monolayer transition metal dichalcogenides (TMDs) are direct gap semiconductors with promising applications in diverse optoelectronic devices. To improve devices’ performance, recent investigations have been systematically focused on the tuning of their optical properties. However, an all-optical approach with the reversible feature is still a challenge. Here we demonstrate the tunability of the photoluminescence (PL) properties of monolayer WS2 via laser irradiation. The broad-range and continuous modulation of PL intensity, as well as the conversion between neutral and charged excitons have been readily and reversibly achieved by only switching the two laser power densities. We attribute the reversible manipulation to the laser-assisted adsorption and desorption of gas molecules, which will deplete or release free electrons from the surface of WS2 and thus modify its PL properties. This all-optical manipulation, with advantages of reversibility, quantitative control, and high spatial resolution, suggests promising applications of TMDs monolayers in optoelectronic and nanophotonic applications, such as erasable optical data storage, micropatterning, and display.
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Affiliation(s)
- Chaoli Yang
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan 030006, Shanxi, China; (C.Y.); (Y.G.); (X.L.); (S.H.); (G.Z.); (R.C.); (J.H.); (S.J.)
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, Shanxi, China
| | - Yan Gao
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan 030006, Shanxi, China; (C.Y.); (Y.G.); (X.L.); (S.H.); (G.Z.); (R.C.); (J.H.); (S.J.)
- Department of Physics, Shanxi Datong University, Datong 037009, Shanxi, China
| | - Chengbing Qin
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan 030006, Shanxi, China; (C.Y.); (Y.G.); (X.L.); (S.H.); (G.Z.); (R.C.); (J.H.); (S.J.)
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, Shanxi, China
- Correspondence: (C.Q.); (L.X.)
| | - Xilong Liang
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan 030006, Shanxi, China; (C.Y.); (Y.G.); (X.L.); (S.H.); (G.Z.); (R.C.); (J.H.); (S.J.)
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, Shanxi, China
| | - Shuangping Han
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan 030006, Shanxi, China; (C.Y.); (Y.G.); (X.L.); (S.H.); (G.Z.); (R.C.); (J.H.); (S.J.)
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, Shanxi, China
| | - Guofeng Zhang
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan 030006, Shanxi, China; (C.Y.); (Y.G.); (X.L.); (S.H.); (G.Z.); (R.C.); (J.H.); (S.J.)
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, Shanxi, China
| | - Ruiyun Chen
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan 030006, Shanxi, China; (C.Y.); (Y.G.); (X.L.); (S.H.); (G.Z.); (R.C.); (J.H.); (S.J.)
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, Shanxi, China
| | - Jianyong Hu
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan 030006, Shanxi, China; (C.Y.); (Y.G.); (X.L.); (S.H.); (G.Z.); (R.C.); (J.H.); (S.J.)
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, Shanxi, China
| | - Liantuan Xiao
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan 030006, Shanxi, China; (C.Y.); (Y.G.); (X.L.); (S.H.); (G.Z.); (R.C.); (J.H.); (S.J.)
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, Shanxi, China
- Correspondence: (C.Q.); (L.X.)
| | - Suotang Jia
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan 030006, Shanxi, China; (C.Y.); (Y.G.); (X.L.); (S.H.); (G.Z.); (R.C.); (J.H.); (S.J.)
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, Shanxi, China
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27
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Carrier multiplication in van der Waals layered transition metal dichalcogenides. Nat Commun 2019; 10:5488. [PMID: 31792222 PMCID: PMC6889496 DOI: 10.1038/s41467-019-13325-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 10/30/2019] [Indexed: 11/17/2022] Open
Abstract
Carrier multiplication (CM) is a process in which high-energy free carriers relax by generation of additional electron-hole pairs rather than by heat dissipation. CM is promising disruptive improvements in photovoltaic energy conversion and light detection technologies. Current state-of-the-art nanomaterials including quantum dots and carbon nanotubes have demonstrated CM, but are not satisfactory owing to high-energy-loss and inherent difficulties with carrier extraction. Here, we report CM in van der Waals (vdW) MoTe2 and WSe2 films, and find characteristics, commencing close to the energy conservation limit and reaching up to 99% CM conversion efficiency with the standard model. This is demonstrated by ultrafast optical spectroscopy with independent approaches, photo-induced absorption, photo-induced bleach, and carrier population dynamics. Combined with a high lateral conductivity and an optimal bandgap below 1 eV, these superior CM characteristics identify vdW materials as an attractive candidate material for highly efficient and mechanically flexible solar cells in the future. During carrier multiplication, high-energy free carriers in a given material relax by generation of additional electron-hole pairs. Here, the authors report evidence of carrier multiplication in multilayer MoTe2 and WSe2 films with up to 99% conversation efficiency.
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28
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Kim K, Lee JU, Cheong H. Raman spectroscopy of two-dimensional magnetic van der Waals materials. NANOTECHNOLOGY 2019; 30:452001. [PMID: 31370047 DOI: 10.1088/1361-6528/ab37a4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Two-dimensional magnetic van der Waals (vdW) materials have attracted much interest recently. Magnetism in two dimensions is one of the most fascinating topics in condensed matter physics whereas atomically thin magnetic materials present new opportunities for novel spintronic devices. Raman spectroscopy has been established as an invaluable tool in the studies of such magnetic vdW materials as it has been found that the magnetic ordering, which is often difficult to probe directly in atomically thin samples, can be reliably monitored by Raman spectroscopy. Here, we review recent progress in using Raman spectroscopy for the study of magnetic vdW materials with the examples of Ising-type ferromagnet CrI3, Ising-type antiferromagnet FePS3, and XY-type antiferromagnet NiPS3. By monitoring characteristic spectroscopic signatures of magnetic ordering, one can probe various aspects of magnetic ordering.
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Affiliation(s)
- Kangwon Kim
- Department of Physics, Sogang University, Seoul 04107, Republic of Korea
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29
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Mao N, Wang X, Lin Y, Sumpter BG, Ji Q, Palacios T, Huang S, Meunier V, Dresselhaus MS, Tisdale WA, Liang L, Ling X, Kong J. Direct Observation of Symmetry-Dependent Electron–Phonon Coupling in Black Phosphorus. J Am Chem Soc 2019; 141:18994-19001. [DOI: 10.1021/jacs.9b07974] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | | | | | | | | | - Shengxi Huang
- Department of Electrical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Vincent Meunier
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
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30
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Zhang D, Du J, Hong YL, Zhang W, Wang X, Jin H, Burn PL, Yu J, Chen M, Sun DM, Li M, Liu L, Ma LP, Cheng HM, Ren W. A Double Support Layer for Facile Clean Transfer of Two-Dimensional Materials for High-Performance Electronic and Optoelectronic Devices. ACS NANO 2019; 13:5513-5522. [PMID: 31013418 DOI: 10.1021/acsnano.9b00330] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Clean transfer of two-dimensional (2D) materials grown by chemical vapor deposition is critical for their application in electronics and optoelectronics. Although rosin can be used as a support layer for the clean transfer of graphene grown on Cu, it has not been usable for the transfer of 2D materials grown on noble metals or for large-area transfer. Here, we report a poly(methyl methacrylate) (PMMA)/rosin double support layer that enables facile ultraclean transfer of large-area 2D materials grown on different metals. The bottom rosin layer ensures clean transfer, whereas the top PMMA layer not only screens the rosin from the transfer conditions but also improves the strength of the transfer layer to make the transfer easier and more robust. We demonstrate the transfer of monolayer WSe2 and WS2 single crystals grown on Au as well as large-area graphene films grown on Cu. As a result of the clean surface, the transferred WSe2 retains the intrinsic optical properties of the as-grown sample. Moreover, it does not require annealing to form good ohmic contacts with metal electrodes, enabling high-performance field effect transistors with mobility and ON/OFF ratio ∼10 times higher than those made by PMMA-transferred WSe2. The ultraclean graphene film is found to be a good anode for flexible organic photovoltaic cells with a high power conversion efficiency of ∼6.4% achieved.
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Affiliation(s)
- Dingdong Zhang
- Shenyang National Laboratory for Materials Science , Institute of Metal Research, Chinese Academy of Sciences , 72 Wenhua Road , Shenyang 110016 , P.R. China
- School of Materials Science and Engineering , University of Science and Technology of China , 72 Wenhua Road , Shenyang 110016 , P.R. China
| | - Jinhong Du
- Shenyang National Laboratory for Materials Science , Institute of Metal Research, Chinese Academy of Sciences , 72 Wenhua Road , Shenyang 110016 , P.R. China
- School of Materials Science and Engineering , University of Science and Technology of China , 72 Wenhua Road , Shenyang 110016 , P.R. China
| | - Yi-Lun Hong
- Shenyang National Laboratory for Materials Science , Institute of Metal Research, Chinese Academy of Sciences , 72 Wenhua Road , Shenyang 110016 , P.R. China
- School of Materials Science and Engineering , University of Science and Technology of China , 72 Wenhua Road , Shenyang 110016 , P.R. China
| | - Weimin Zhang
- Shenyang National Laboratory for Materials Science , Institute of Metal Research, Chinese Academy of Sciences , 72 Wenhua Road , Shenyang 110016 , P.R. China
- School of Materials Science and Engineering , University of Science and Technology of China , 72 Wenhua Road , Shenyang 110016 , P.R. China
| | - Xiao Wang
- Centre for Organic Photonics & Electronics, School of Chemistry and Molecular Biosciences , The University of Queensland , Brisbane QLD 4072 , Australia
- State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Science and Engineering , University of Electronic Science and Technology of China (UESTC) , Chengdu 610054 , P.R. China
| | - Hui Jin
- Centre for Organic Photonics & Electronics, School of Chemistry and Molecular Biosciences , The University of Queensland , Brisbane QLD 4072 , Australia
| | - Paul L Burn
- Centre for Organic Photonics & Electronics, School of Chemistry and Molecular Biosciences , The University of Queensland , Brisbane QLD 4072 , Australia
| | - Junsheng Yu
- State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Science and Engineering , University of Electronic Science and Technology of China (UESTC) , Chengdu 610054 , P.R. China
| | - Maolin Chen
- Shenyang National Laboratory for Materials Science , Institute of Metal Research, Chinese Academy of Sciences , 72 Wenhua Road , Shenyang 110016 , P.R. China
- School of Materials Science and Engineering , University of Science and Technology of China , 72 Wenhua Road , Shenyang 110016 , P.R. China
| | - Dong-Ming Sun
- Shenyang National Laboratory for Materials Science , Institute of Metal Research, Chinese Academy of Sciences , 72 Wenhua Road , Shenyang 110016 , P.R. China
- School of Materials Science and Engineering , University of Science and Technology of China , 72 Wenhua Road , Shenyang 110016 , P.R. China
| | - Meng Li
- Shenyang Institute of Automation , Chinese Academy of Sciences , 114 Nanta Street , Shenyang 110016 , P.R. China
| | - Lianqing Liu
- Shenyang Institute of Automation , Chinese Academy of Sciences , 114 Nanta Street , Shenyang 110016 , P.R. China
| | - Lai-Peng Ma
- Shenyang National Laboratory for Materials Science , Institute of Metal Research, Chinese Academy of Sciences , 72 Wenhua Road , Shenyang 110016 , P.R. China
- School of Materials Science and Engineering , University of Science and Technology of China , 72 Wenhua Road , Shenyang 110016 , P.R. China
| | - Hui-Ming Cheng
- Shenyang National Laboratory for Materials Science , Institute of Metal Research, Chinese Academy of Sciences , 72 Wenhua Road , Shenyang 110016 , P.R. China
- School of Materials Science and Engineering , University of Science and Technology of China , 72 Wenhua Road , Shenyang 110016 , P.R. China
- Shenzhen Geim Graphene Center, Tsinghua-Berkeley Shenzhen Institute , Tsinghua University , 1001 Xueyuan Road , Shenzhen 518055 , P.R. China
| | - Wencai Ren
- Shenyang National Laboratory for Materials Science , Institute of Metal Research, Chinese Academy of Sciences , 72 Wenhua Road , Shenyang 110016 , P.R. China
- School of Materials Science and Engineering , University of Science and Technology of China , 72 Wenhua Road , Shenyang 110016 , P.R. China
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31
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Wang S, Luo Q, Fang WH, Long R. Interfacial Engineering Determines Band Alignment and Steers Charge Separation and Recombination at an Inorganic Perovskite Quantum Dot/WS 2 Junction: A Time Domain Ab Initio Study. J Phys Chem Lett 2019; 10:1234-1241. [PMID: 30818951 DOI: 10.1021/acs.jpclett.9b00285] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Using time-domain density functional theory and nonadiabatic (NA) molecular dynamics, we demonstrate that interfacial interaction between WS2 and CsPbBr3 quantum dots (QDs) determines the band alignment, leading to a type-II and type-I heterojunction for the WS2 contacting with Cs/Br- and PbBr2-terminated facet QD, respectively. In the type-II heterojunction, electron transfer is faster than hole transfer arising due to the stronger NA coupling, higher density of electron acceptor states, and more and higher phonon modes involved. Both the electron and hole transfer times are subpicosecond, in agreement with experiments. The energy lost by the electron and hole is slower than charge transfer by several times, facilitating keeping charge carriers sufficiently "hot". Particularly, the electron-hole recombination occurs over 1 ns, favoring a long-lived charge-separated state. Detailed atomistic insights into the photoinduced charge and energy dynamics at the WS2/QD interface provide valuable guidelines for improving performance of perovskite/transition-metal dichalcogenide solar cells.
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Affiliation(s)
- Siyu Wang
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education , Beijing Normal University , Beijing 100875 , People's Republic of China
| | - Qiquan Luo
- Hefei National Laboratory for Physical Sciences at the Microscale , University of Science and Technology of China , Hefei 230026 , People's Republic of China
| | - Wei-Hai Fang
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education , Beijing Normal University , Beijing 100875 , People's Republic of China
| | - Run Long
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education , Beijing Normal University , Beijing 100875 , People's Republic of China
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32
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Kim K, Lim SY, Lee JU, Lee S, Kim TY, Park K, Jeon GS, Park CH, Park JG, Cheong H. Suppression of magnetic ordering in XXZ-type antiferromagnetic monolayer NiPS 3. Nat Commun 2019; 10:345. [PMID: 30664705 PMCID: PMC6341093 DOI: 10.1038/s41467-018-08284-6] [Citation(s) in RCA: 104] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 12/27/2018] [Indexed: 12/24/2022] Open
Abstract
How a certain ground state of complex physical systems emerges, especially in two-dimensional materials, is a fundamental question in condensed-matter physics. A particularly interesting case is systems belonging to the class of XY Hamiltonian where the magnetic order parameter of conventional nature is unstable in two-dimensional materials leading to a Berezinskii-Kosterlitz-Thouless transition. Here, we report how the XXZ-type antiferromagnetic order of a magnetic van der Waals material, NiPS3, behaves upon reducing the thickness and ultimately becomes unstable in the monolayer limit. Our experimental data are consistent with the findings based on renormalization-group theory that at low temperatures a two-dimensional XXZ system behaves like a two-dimensional XY one, which cannot have a long-range order at finite temperatures. This work provides the experimental examination of the XY magnetism in the atomically thin limit and opens opportunities of exploiting these fundamental theorems of magnetism using magnetic van der Waals materials.
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Affiliation(s)
- Kangwon Kim
- Department of Physics, Sogang University, Seoul, 04107, Korea
| | - Soo Yeon Lim
- Department of Physics, Sogang University, Seoul, 04107, Korea
| | - Jae-Ung Lee
- Department of Physics, Sogang University, Seoul, 04107, Korea
| | - Sungmin Lee
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea
| | - Tae Yun Kim
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea
- Center for Theoretical Physics, Seoul National University, Seoul, 08826, Korea
| | - Kisoo Park
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea
| | - Gun Sang Jeon
- Department of Physics, Ewha Womans University, Seoul, 03760, Korea
| | - Cheol-Hwan Park
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea.
- Center for Theoretical Physics, Seoul National University, Seoul, 08826, Korea.
| | - Je-Geun Park
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Korea.
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea.
| | - Hyeonsik Cheong
- Department of Physics, Sogang University, Seoul, 04107, Korea.
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33
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Liu HL, Yang T, Tatsumi Y, Zhang Y, Dong B, Guo H, Zhang Z, Kumamoto Y, Li MY, Li LJ, Saito R, Kawata S. Deep-ultraviolet Raman scattering spectroscopy of monolayer WS 2. Sci Rep 2018; 8:11398. [PMID: 30061708 PMCID: PMC6065453 DOI: 10.1038/s41598-018-29587-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 07/09/2018] [Indexed: 11/08/2022] Open
Abstract
Raman scattering measurements of monolayer WS2 are reported as a function of the laser excitation energies from the near-infrared (1.58 eV) to the deep-ultraviolet (4.82 eV). In particular, we observed several strong Raman peaks in the range of 700∼850 cm-1 with the deep-ultraviolet laser lights (4.66 eV and 4.82 eV). Using the first-principles calculations, these peaks and other weak peaks were appropriately assigned by the double resonance Raman scattering spectra of phonons around the M and K points in the hexagonal Brillouin zone. The relative intensity of the first-order [Formula: see text] to A1g peak changes dramatically with the 1.58 eV and 2.33 eV laser excitations, while the comparable relative intensity was observed for other laser energies. The disappearance of the [Formula: see text] peak with the 1.58 eV laser light comes from the fact that valley polarization of the laser light surpasses the [Formula: see text] mode since the [Formula: see text] mode is the helicity-exchange Raman mode. On the other hand, the disappearance of the A1g peak with the 2.33 eV laser light might be due to the strain effect on the electron-phonon matrix element.
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Affiliation(s)
- Hsiang-Lin Liu
- Department of Physics, National Taiwan Normal University, Taipei, 11677, Taiwan.
| | - Teng Yang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang, 110016, China.
- Department of Physics, Tohoku University, Sendai, 980-8578, Japan.
| | - Yuki Tatsumi
- Department of Physics, Tohoku University, Sendai, 980-8578, Japan
| | - Ye Zhang
- College of Sciences, Liaoning Shihua University, Fushun, 113001, China
| | - Baojuan Dong
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang, 110016, China
| | - Huaihong Guo
- Department of Physics, Tohoku University, Sendai, 980-8578, Japan
- College of Sciences, Liaoning Shihua University, Fushun, 113001, China
| | - Zhidong Zhang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang, 110016, China
| | - Yasuaki Kumamoto
- Department of Applied Physics, Osaka University 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
- Department of Pathology and Cell Regulation, Graduate School of Medical Sciences, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Ming-Yang Li
- Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
- Research Center for Applied Science, Academia Sinica, Taipei, 10617, Taiwan
| | - Lain-Jong Li
- Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Riichiro Saito
- Department of Physics, Tohoku University, Sendai, 980-8578, Japan
| | - Satoshi Kawata
- Department of Applied Physics, Osaka University 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
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Jiang J, Pachter R, Mou S. Tunability in the optical response of defective monolayer WSe 2 by computational analysis. NANOSCALE 2018; 10:13751-13760. [PMID: 29993082 DOI: 10.1039/c8nr02906g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In aiming to achieve red-shifted single-photon emitters that result from localized excitons in monolayer WSe2, we report in this work a theoretical investigation on the optical properties of nanostructures with vacancies and rotational defects. We find that for pristine monolayer WSe2, the complex excitonic manifold, namely, the energies of the bright and dark excitons and the exciton binding energy, agree well with the experimental data when using the GW (Green's function approximation with a screened Coulomb interaction W)-Bethe Salpeter Equation (GW-BSE) method, including spin-orbit coupling. The predicted second and third lowest dark excitons are close in energy and appear below the second bright exciton. Upon introduction of single or double Se vacancies, or a single W vacancy within monolayer WSe2, accurate computational results demonstrate emergence of deeper defect excitons in comparison to shallower values observed for edges, which are consistent with measured emissions upon Ar+ plasma treatment of WSe2 for longer periods of time. Furthermore, using corrected RPA (random phase approximation) calculations, we find that defect excitons red-shift significantly for large rotational defects that pattern the monolayer. Finally, interestingly, first-order Raman intensity calculations demonstrate that a comparison between pristine and defective monolayer WSe2 with a single vacancy can provide a fingerprint for defect characterization. Overall, our results will encourage experimental defect engineering to enable the development of red-shifted single-photon emitters, such as by inducing extended patterning of monolayer WSe2.
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Affiliation(s)
- Jie Jiang
- Air Force Research Laboratory, Wright-Patterson Air Force Base, OH 45433, USA.
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35
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Krasnok A, Lepeshov S, Alú A. Nanophotonics with 2D transition metal dichalcogenides [Invited]. OPTICS EXPRESS 2018; 26:15972-15994. [PMID: 30114850 DOI: 10.1364/oe.26.015972] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 04/17/2018] [Indexed: 06/08/2023]
Abstract
Two-dimensional semiconducting transition metal dichalcogenides (TMDCs) have recently become attractive materials for several optoelectronic applications, such as photodetection, light harvesting, phototransistors, light-emitting diodes, and lasers. Their bandgap lies in the visible and near-IR range, and they possess strong excitonic resonances, high oscillator strengths, and valley-selective response. Coupling these materials to optical nanocavities enhances the quantum yield of exciton emission, enabling advanced quantum optics and nanophotonics devices. Here, we review the state-of-the-art advances of hybrid exciton-polariton structures based on monolayer TMDCs coupled to plasmonic and dielectric nanocavities. We discuss the optical properties of 2D WS2, WSe2, MoS2 and MoSe2 materials, paying special attention to their energy bands, photoluminescence/absorption spectra, excitonic fine structure, and to the dynamics of exciton formation and valley depolarization. We also discuss light-matter interactions in such hybrid exciton-polariton structures. Finally, we focus on weak and strong coupling regimes in monolayer TMDCs-based exciton-polariton systems, envisioning research directions and future opportunities for this material platform.
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36
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Lepeshov S, Wang M, Krasnok A, Kotov O, Zhang T, Liu H, Jiang T, Korgel B, Terrones M, Zheng Y, Alú A. Tunable Resonance Coupling in Single Si Nanoparticle-Monolayer WS 2 Structures. ACS APPLIED MATERIALS & INTERFACES 2018; 10:16690-16697. [PMID: 29651843 DOI: 10.1021/acsami.7b17112] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Two-dimensional semiconducting transition metal dichalcogenides (TMDCs) are extremely attractive materials for optoelectronic applications in the visible and near-infrared range. Coupling these materials to optical nanocavities enables advanced quantum optics and nanophotonic devices. Here, we address the issue of resonance coupling in hybrid exciton-polariton structures based on single Si nanoparticles (NPs) coupled to monolayer (1L)-WS2. We predict a strong coupling regime with a Rabi splitting energy exceeding 110 meV for a Si NP covered by 1L-WS2 at the magnetic optical Mie resonance because of the symmetry of the mode. Further, we achieve a large enhancement in the Rabi splitting energy up to 208 meV by changing the surrounding dielectric material from air to water. The prediction is based on the experimental estimation of TMDC dipole moment variation obtained from the measured photoluminescence spectra of 1L-WS2 in different solvents. An ability of such a system to tune the resonance coupling is realized experimentally for optically resonant spherical Si NPs placed on 1L-WS2. The Rabi splitting energy obtained for this scenario increases from 49.6 to 86.6 meV after replacing air by water. Our findings pave the way to develop high-efficiency optoelectronic, nanophotonic, and quantum optical devices.
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Affiliation(s)
| | | | | | - Oleg Kotov
- Institute of MicroelectronicsTechnology and High Purity Materials , Russian Academy of Sciences , 142432 Chernogolovka , Russia
| | | | | | | | | | - Mauricio Terrones
- Department of Materials Science and Engineering & Chemical Engineering , Carlos III University of Madrid , Avenida Universidad 30 , Leganés, Madrid 28911 , Spain
- IMDEA Materials Institute , Eric Kandel 2 , Getafe, Madrid 28005 , Spain
| | | | - Andrea Alú
- Photonics Initiative, Advanced Science Research Center , City University of New York , New York , New York 10031 , United States
- Physics Program, Graduate Center , City University of New York , New York 10016 , United States
- Department of Electrical Engineering , City College of The City University of New York , New York 10031 , United States
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37
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McDonnell LP, Huang CC, Cui Q, Hewak DW, Smith DC. Probing Excitons, Trions, and Dark Excitons in Monolayer WS 2 Using Resonance Raman Spectroscopy. NANO LETTERS 2018; 18:1428-1434. [PMID: 29297693 DOI: 10.1021/acs.nanolett.7b05184] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
We present temperature-dependent resonance Raman measurements on monolayer WS2 for the temperature range 4-295 K using excitation photon energies from 1.9 to 2.15 eV in ∼7 meV steps. These are analyzed to determine the resonance profiles of five previously assigned phonon based Raman peaks (A1', E', 2ZA, LA, 2LA) and a previously unassigned peak at 485 cm-1 whose possible attributions are discussed. The resonance profiles obtained are fitted to a perturbation theory derived model and it is shown that both excitons and trions are required to explain the profiles. The model is used to separate the contribution of exciton-exciton, trion-trion, and exciton-trion scattering to each of the Raman peaks at 4 K. This separation allows the ratios of the rates of scattering involving the A1' and E' phonons for each of the three types of scattering to be determined. The explanation of the multiphonon Raman peaks requires the coupling of bright excitons and trions to large wavevector dark states. The fitting of the resonance Raman profiles for these Raman peaks demonstrates scattering of bright excitons to bright trions via these large wavevector dark states.
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Affiliation(s)
- Liam P McDonnell
- School of Physics and Astronomy and ‡Optoelectronic Research Centre, University of Southampton , Southampton SO17 1BJ, United Kingdom
| | - Chung-Che Huang
- School of Physics and Astronomy and ‡Optoelectronic Research Centre, University of Southampton , Southampton SO17 1BJ, United Kingdom
| | - Qingsong Cui
- School of Physics and Astronomy and ‡Optoelectronic Research Centre, University of Southampton , Southampton SO17 1BJ, United Kingdom
| | - Dan W Hewak
- School of Physics and Astronomy and ‡Optoelectronic Research Centre, University of Southampton , Southampton SO17 1BJ, United Kingdom
| | - David C Smith
- School of Physics and Astronomy and ‡Optoelectronic Research Centre, University of Southampton , Southampton SO17 1BJ, United Kingdom
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38
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Wang D, Li Q, Han C, Xing Z, Yang X. When NiO@Ni Meets WS 2 Nanosheet Array: A Highly Efficient and Ultrastable Electrocatalyst for Overall Water Splitting. ACS CENTRAL SCIENCE 2018; 4:112-119. [PMID: 29392183 PMCID: PMC5785763 DOI: 10.1021/acscentsci.7b00502] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Indexed: 05/25/2023]
Abstract
The development of low-cost, high-efficiency, and stable bifunctional electrocatalysts toward the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is of paramount importance for large-scale water splitting. Here, we develop a new strategy for the first design and synthesis of a NiO@Ni decorated WS2 nanosheet array on carbon cloth (NiO@Ni/WS2/CC) composite. This composite serves as a unique three-dimensional (3D) synergistic electrocatalyst that not only combines the intrinsic properties of individual NiO@Ni and WS2, but also exhibits significantly improved HER and OER activities when compared to that of pure NiO@Ni and WS2. This electrocatalyst possesses Pt-like activity for HER and exhibits better OER performance than that for commercial RuO2, as well as demonstrating superior long-term durability in alkaline media. Furthermore, it enables an alkaline electrolyzer with a current density of 10 mA cm-2 at a cell voltage as 1.42 V, which is the lowest one among all reported values to date. The excellent performance is mainly attributed to the unique 3D configuration and multicomponent synergies among NiO, Ni, and WS2. Our findings provide a new idea to design advanced bifunctional catalysts for water splitting.
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Affiliation(s)
- Dewen Wang
- State
Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, Jilin, China
- University
of Science and Technology of China, Hefei 230026, China
| | - Qun Li
- State
Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, Jilin, China
- University
of Science and Technology of China, Hefei 230026, China
| | - Ce Han
- State
Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, Jilin, China
| | - Zhicai Xing
- State
Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, Jilin, China
| | - Xiurong Yang
- State
Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, Jilin, China
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39
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Bilgin I, Raeliarijaona AS, Lucking MC, Hodge SC, Mohite AD, de Luna Bugallo A, Terrones H, Kar S. Resonant Raman and Exciton Coupling in High-Quality Single Crystals of Atomically Thin Molybdenum Diselenide Grown by Vapor-Phase Chalcogenization. ACS NANO 2018; 12:740-750. [PMID: 29281260 DOI: 10.1021/acsnano.7b07933] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We report a detailed investigation on Raman spectroscopy in vapor-phase chalcogenization grown, high-quality single-crystal atomically thin molybdenum diselenide samples. Measurements were performed in samples with four different incident laser excitation energies ranging from 1.95 eV ⩽ Eex ⩽ 2.71 eV, revealing rich spectral information in samples ranging from N = 1-4 layers and a thick, bulk sample. In addition to previously observed (and identified) peaks, we specifically investigate the origin of a peak near ω ≈ 250 cm-1. Our density functional theory and Bethe-Salpeter calculations suggest that this peak arises from a double-resonant Raman process involving the ZA acoustic phonon perpendicular to the layer. This mode appears prominently in freshly prepared samples and disappears in aged samples, thereby offering a method for ascertaining the high optoelectronic quality of freshly prepared 2D-MoSe2 crystals. We further present an in-depth investigation of the energy-dependent variation of the position of this and other peaks and provide evidence of C-exciton-phonon coupling in monolayer MoSe2. Finally, we show how the signature peak positions and intensities vary as a function of layer thickness in these samples.
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Affiliation(s)
- Ismail Bilgin
- Department of Physics, Northeastern University , Boston, Massachusetts 02115, United States
| | - Aldo S Raeliarijaona
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute , Troy, New York 12180, United States
| | - Michael C Lucking
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute , Troy, New York 12180, United States
| | - Sebastian Cooper Hodge
- Department of Physics, Northeastern University , Boston, Massachusetts 02115, United States
| | - Aditya D Mohite
- Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
| | - Andres de Luna Bugallo
- Department of Physics, Northeastern University , Boston, Massachusetts 02115, United States
- CONACYT - Cinvestav Unidad Querétaro , Querétaro, Qro 76230, Mexico
| | - Humberto Terrones
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute , Troy, New York 12180, United States
| | - Swastik Kar
- Department of Physics, Northeastern University , Boston, Massachusetts 02115, United States
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40
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Webster L, Liang L, Yan JA. Distinct spin–lattice and spin–phonon interactions in monolayer magnetic CrI3. Phys Chem Chem Phys 2018; 20:23546-23555. [DOI: 10.1039/c8cp03599g] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Different magnetic ordering leads to distinct Raman response in monolayer CrI3.
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Affiliation(s)
- Lucas Webster
- Department of Physics
- Astronomy, and Geosciences
- Towson University
- Towson
- USA
| | - Liangbo Liang
- Center for Nanophase Materials Sciences
- Oak Ridge National Laboratory
- Oak Ridge
- USA
| | - Jia-An Yan
- Department of Physics
- Astronomy, and Geosciences
- Towson University
- Towson
- USA
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41
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Hill HM, Rigosi AF, Krylyuk S, Tian J, Nguyen NV, Davydov AV, Newell DB, Walker ARH. Comprehensive optical characterization of atomically thin NbSe 2. PHYSICAL REVIEW. B 2018; 98:10.1103/PhysRevB.98.165109. [PMID: 30984898 PMCID: PMC6459197 DOI: 10.1103/physrevb.98.165109] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Transition-metal dichalcogenides (TMDCs) have offered experimental access to quantum confinement in one dimension. In recent years, metallic TMDCs like NbSe2 have taken center stage with many of them exhibiting interesting temperature-dependent properties such as charge density waves and superconductivity. In this paper, we perform a comprehensive optical analysis of NbSe2 by utilizing Raman spectroscopy, differential reflectance contrast, and spectroscopic ellipsometry. These analyses, when coupled with Kramers-Kronig analysis, allow us to extract the dielectric functions of bulk and atomically thin NbSe2 and relate them to the resonant behavior of the Raman spectra.
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Affiliation(s)
- Heather M. Hill
- Physical Measurement Laboratory, National Institute of
Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Albert F. Rigosi
- Physical Measurement Laboratory, National Institute of
Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Sergiy Krylyuk
- Material Measurement Laboratory, National Institute of
Standards and Technology, Gaithersburg, Maryland 20899, USA
- Theiss Research, Inc., La Jolla, California 92037,
USA
| | - Jifa Tian
- Physical Measurement Laboratory, National Institute of
Standards and Technology, Gaithersburg, Maryland 20899, USA
- Department of Physics and Astronomy, and Birck
Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA
| | - Nhan V. Nguyen
- Physical Measurement Laboratory, National Institute of
Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Albert V. Davydov
- Material Measurement Laboratory, National Institute of
Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - David B. Newell
- Physical Measurement Laboratory, National Institute of
Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Angela R. Hight Walker
- Physical Measurement Laboratory, National Institute of
Standards and Technology, Gaithersburg, Maryland 20899, USA
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42
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Liang L, Zhang J, Sumpter BG, Tan QH, Tan PH, Meunier V. Low-Frequency Shear and Layer-Breathing Modes in Raman Scattering of Two-Dimensional Materials. ACS NANO 2017; 11:11777-11802. [PMID: 29099577 DOI: 10.1021/acsnano.7b06551] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Ever since the isolation of single-layer graphene in 2004, two-dimensional layered structures have been among the most extensively studied classes of materials. To date, the pool of two-dimensional materials (2DMs) continues to grow at an accelerated pace and already covers an extensive range of fascinating and technologically relevant properties. An array of experimental techniques have been developed and used to characterize and understand these properties. In particular, Raman spectroscopy has proven to be a key experimental technique, thanks to its capability to identify minute structural and electronic effects in nondestructive measurements. While high-frequency (HF) intralayer Raman modes have been extensively employed for 2DMs, recent experimental and theoretical progress has demonstrated that low-frequency (LF) interlayer Raman modes are more effective at determining layer numbers and stacking configurations and provide a unique opportunity to study interlayer coupling. These advantages are due to 2DMs' unique interlayer vibration patterns where each layer behaves as an almost rigidly moving object with restoring forces corresponding to weak interlayer interactions. Compared to HF Raman modes, the relatively small attention originally devoted to LF Raman modes is largely due to their weaker signal and their proximity to the strong Rayleigh line background, which previously made their detection challenging. Recent progress in Raman spectroscopy with technical and hardware upgrades now makes it possible to probe LF modes with a standard single-stage Raman system and has proven crucial to characterize and understand properties of 2DMs. Here, we present a comprehensive and forward-looking review on the current status of exploiting LF Raman modes of 2DMs from both experimental and theoretical perspectives, revealing the fundamental physics and technological significance of LF Raman modes in advancing the field of 2DMs. We review a broad array of materials, with varying thickness and stacking configurations, discuss the effect of in-plane anisotropy, and present a generalized linear chain model and interlayer bond polarizability model to rationalize the experimental findings. We also discuss the instrumental improvements of Raman spectroscopy to enhance and separate LF Raman signals from the Rayleigh line. Finally, we highlight the opportunities and challenges ahead in this fast-developing field.
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Affiliation(s)
- Liangbo Liang
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Jun Zhang
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences , Beijing 100083, China
- CAS Center of Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences , Beijing 100190, China
| | - Bobby G Sumpter
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Qing-Hai Tan
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences , Beijing 100083, China
- CAS Center of Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences , Beijing 100190, China
| | - Ping-Heng Tan
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences , Beijing 100083, China
- CAS Center of Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences , Beijing 100190, China
| | - Vincent Meunier
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute , Troy, New York 12180, United States
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McCreary A, Simpson JR, Wang Y, Rhodes D, Fujisawa K, Balicas L, Dubey M, Crespi VH, Terrones M, Hight Walker AR. Intricate Resonant Raman Response in Anisotropic ReS 2. NANO LETTERS 2017; 17:5897-5907. [PMID: 28820602 DOI: 10.1021/acs.nanolett.7b01463] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The strong in-plane anisotropy of rhenium disulfide (ReS2) offers an additional physical parameter that can be tuned for advanced applications such as logic circuits, thin-film polarizers, and polarization-sensitive photodetectors. ReS2 also presents advantages for optoelectronics, as it is both a direct-gap semiconductor for few-layer thicknesses (unlike MoS2 or WS2) and stable in air (unlike black phosphorus). Raman spectroscopy is one of the most powerful characterization techniques to nondestructively and sensitively probe the fundamental photophysics of a 2D material. Here, we perform a thorough study of the resonant Raman response of the 18 first-order phonons in ReS2 at various layer thicknesses and crystal orientations. Remarkably, we discover that, as opposed to a general increase in intensity of all of the Raman modes at excitonic transitions, each of the 18 modes behave differently relative to each other as a function of laser excitation, layer thickness, and orientation in a manner that highlights the importance of electron-phonon coupling in ReS2. In addition, we correct an unrecognized error in the calculation of the optical interference enhancement of the Raman signal of transition metal dichalcogenides on SiO2/Si substrates that has propagated through various reports. For ReS2, this correction is critical to properly assessing the resonant Raman behavior. We also implemented a perturbation approach to calculate frequency-dependent Raman intensities based on first-principles and demonstrate that, despite the neglect of excitonic effects, useful trends in the Raman intensities of monolayer and bulk ReS2 at different laser energies can be accurately captured. Finally, the phonon dispersion calculated from first-principles is used to address the possible origins of unexplained peaks observed in the Raman spectra, such as infrared-active modes, defects, and second-order processes.
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Affiliation(s)
- Amber McCreary
- Sensors & Electron Devices Directorate, U.S. Army Research Laboratory , Adelphi, Maryland 20783, United States
- Engineering Physics Division, Physical Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
| | - Jeffrey R Simpson
- Engineering Physics Division, Physical Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
- Department of Physics, Astronomy, and Geosciences, Towson University , Towson, Maryland 21252, United States
| | | | - Daniel Rhodes
- Sensors & Electron Devices Directorate, U.S. Army Research Laboratory , Adelphi, Maryland 20783, United States
- Department of Physics and National High Magnetic Field Lab, Florida State University , Tallahassee, Florida 32310, United States
| | | | - Luis Balicas
- Department of Physics and National High Magnetic Field Lab, Florida State University , Tallahassee, Florida 32310, United States
| | - Madan Dubey
- Sensors & Electron Devices Directorate, U.S. Army Research Laboratory , Adelphi, Maryland 20783, United States
| | | | - Mauricio Terrones
- Institute of Carbon Science and Technology, Faculty of Engineering, Shinshu University , Nagano 380-8553, Japan
| | - Angela R Hight Walker
- Engineering Physics Division, Physical Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
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Zhan L, Wan W, Zhu Z, Shih TM, Cai W. MoS2 materials synthesized on SiO2/Si substrates via MBE. ACTA ACUST UNITED AC 2017. [DOI: 10.1088/1742-6596/864/1/012037] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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45
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Ab Initio Approach to Second-order Resonant Raman Scattering Including Exciton-Phonon Interaction. Sci Rep 2017; 7:7344. [PMID: 28779127 PMCID: PMC5544768 DOI: 10.1038/s41598-017-07682-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 06/29/2017] [Indexed: 11/12/2022] Open
Abstract
Raman spectra obtained by the inelastic scattering of light by crystalline solids contain contributions from first-order vibrational processes (e.g. the emission or absorption of one phonon, a quantum of vibration) as well as higher-order processes with at least two phonons being involved. At second order, coupling with the entire phonon spectrum induces a response that may strongly depend on the excitation energy, and reflects complex processes more difficult to interpret. In particular, excitons (i.e. bound electron-hole pairs) may enhance the absorption and emission of light, and couple strongly with phonons in resonance conditions. We design and implement a first-principles methodology to compute second-order Raman scattering, incorporating dielectric responses and phonon eigenstates obtained from density-functional theory and many-body theory. We demonstrate our approach for the case of silicon, relating frequency-dependent relative Raman intensities, that are in excellent agreement with experiment, to different vibrations and regions of the Brillouin zone. We show that exciton-phonon coupling, computed from first principles, indeed strongly affects the spectrum in resonance conditions. The ability to analyze second-order Raman spectra thus provides direct insight into this interaction.
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Abstract
Resonant Raman scattering is investigated in monolayer WS2 at low temperature with the aid of an unconventional technique, i.e., Raman scattering excitation (RSE) spectroscopy. The RSE spectrum is made up by sweeping the excitation energy, when the detection energy is fixed in resonance with excitonic transitions related to either neutral or charged excitons. We demonstrate that the shape of the RSE spectrum strongly depends on the selected detection energy. The resonance of outgoing light with the neutral exciton leads to an extremely rich RSE spectrum, which displays several Raman scattering features not reported so far, while no clear effect on the associated background photoluminescence is observed. Instead, when the outgoing photons resonate with the negatively charged exciton, a strong enhancement of the related emission occurs. Presented results show that the RSE spectroscopy can be a useful technique to study electron-phonon interactions in thin layers of transition metal dichalcogenides.
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47
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Miranda HPC, Reichardt S, Froehlicher G, Molina-Sánchez A, Berciaud S, Wirtz L. Quantum Interference Effects in Resonant Raman Spectroscopy of Single- and Triple-Layer MoTe 2 from First-Principles. NANO LETTERS 2017; 17:2381-2388. [PMID: 28199122 DOI: 10.1021/acs.nanolett.6b05345] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We present a combined experimental and theoretical study of resonant Raman spectroscopy in single- and triple-layer MoTe2. Raman intensities are computed entirely from first-principles by calculating finite differences of the dielectric susceptibility. In our analysis, we investigate the role of quantum interference effects and the electron-phonon coupling. With this method, we explain the experimentally observed intensity inversion of the A1' vibrational modes in triple-layer MoTe2 with increasing laser photon energy. Finally, we show that a quantitative comparison with experimental data requires the proper inclusion of excitonic effects.
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Affiliation(s)
- Henrique P C Miranda
- Physics and Materials Science Research Unit, University of Luxembourg , 162a avenue de la Faïencerie, L-1511 Luxembourg, Luxembourg , EU
| | - Sven Reichardt
- Physics and Materials Science Research Unit, University of Luxembourg , 162a avenue de la Faïencerie, L-1511 Luxembourg, Luxembourg , EU
- JARA-FIT and 2nd Institute of Physics , Otto-Blumenthal-Straße, 52074 Aachen, Germany , EU
| | - Guillaume Froehlicher
- Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg, CNRS , UMR 7504, F-67000 Strasbourg, France , EU
| | - Alejandro Molina-Sánchez
- Physics and Materials Science Research Unit, University of Luxembourg , 162a avenue de la Faïencerie, L-1511 Luxembourg, Luxembourg , EU
| | - Stéphane Berciaud
- Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg, CNRS , UMR 7504, F-67000 Strasbourg, France , EU
| | - Ludger Wirtz
- Physics and Materials Science Research Unit, University of Luxembourg , 162a avenue de la Faïencerie, L-1511 Luxembourg, Luxembourg , EU
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48
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Tangi M, Mishra P, Tseng CC, Ng TK, Hedhili MN, Anjum DH, Alias MS, Wei N, Li LJ, Ooi BS. Band Alignment at GaN/Single-Layer WSe 2 Interface. ACS APPLIED MATERIALS & INTERFACES 2017; 9:9110-9117. [PMID: 28222259 DOI: 10.1021/acsami.6b15370] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We study the band discontinuity at the GaN/single-layer (SL) WSe2 heterointerface. The GaN thin layer is epitaxially grown by molecular beam epitaxy on chemically vapor deposited SL-WSe2/c-sapphire. We confirm that the WSe2 was formed as an SL from structural and optical analyses using atomic force microscopy, scanning transmission electron microscopy, micro-Raman, absorbance, and microphotoluminescence spectra. The determination of band offset parameters at the GaN/SL-WSe2 heterojunction is obtained by high-resolution X-ray photoelectron spectroscopy, electron affinities, and the electronic bandgap values of SL-WSe2 and GaN. The valence band and conduction band offset values are determined to be 2.25 ± 0.15 and 0.80 ± 0.15 eV, respectively, with type II band alignment. The band alignment parameters determined here provide a route toward the integration of group III nitride semiconducting materials with transition metal dichalcogenides (TMDs) for designing and modeling of their heterojunction-based electronic and optoelectronic devices.
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Affiliation(s)
- Malleswararao Tangi
- Photonics Laboratory, Computer, Electrical, and Mathematical Sciences and Engineering (CEMSE) Division, ‡Physical Science and Engineering (PSE) Division, and §Imaging and Characterization Laboratory, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Pawan Mishra
- Photonics Laboratory, Computer, Electrical, and Mathematical Sciences and Engineering (CEMSE) Division, ‡Physical Science and Engineering (PSE) Division, and §Imaging and Characterization Laboratory, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Chien-Chih Tseng
- Photonics Laboratory, Computer, Electrical, and Mathematical Sciences and Engineering (CEMSE) Division, ‡Physical Science and Engineering (PSE) Division, and §Imaging and Characterization Laboratory, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Tien Khee Ng
- Photonics Laboratory, Computer, Electrical, and Mathematical Sciences and Engineering (CEMSE) Division, ‡Physical Science and Engineering (PSE) Division, and §Imaging and Characterization Laboratory, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Mohamed Nejib Hedhili
- Photonics Laboratory, Computer, Electrical, and Mathematical Sciences and Engineering (CEMSE) Division, ‡Physical Science and Engineering (PSE) Division, and §Imaging and Characterization Laboratory, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Dalaver H Anjum
- Photonics Laboratory, Computer, Electrical, and Mathematical Sciences and Engineering (CEMSE) Division, ‡Physical Science and Engineering (PSE) Division, and §Imaging and Characterization Laboratory, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Mohd Sharizal Alias
- Photonics Laboratory, Computer, Electrical, and Mathematical Sciences and Engineering (CEMSE) Division, ‡Physical Science and Engineering (PSE) Division, and §Imaging and Characterization Laboratory, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Nini Wei
- Photonics Laboratory, Computer, Electrical, and Mathematical Sciences and Engineering (CEMSE) Division, ‡Physical Science and Engineering (PSE) Division, and §Imaging and Characterization Laboratory, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Lain-Jong Li
- Photonics Laboratory, Computer, Electrical, and Mathematical Sciences and Engineering (CEMSE) Division, ‡Physical Science and Engineering (PSE) Division, and §Imaging and Characterization Laboratory, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Boon S Ooi
- Photonics Laboratory, Computer, Electrical, and Mathematical Sciences and Engineering (CEMSE) Division, ‡Physical Science and Engineering (PSE) Division, and §Imaging and Characterization Laboratory, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
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49
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Kim K, Lee JU, Nam D, Cheong H. Davydov Splitting and Excitonic Resonance Effects in Raman Spectra of Few-Layer MoSe2. ACS NANO 2016; 10:8113-8120. [PMID: 27479147 DOI: 10.1021/acsnano.6b04471] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Raman spectra of few-layer MoSe2 were measured with eight excitation energies. New peaks that appear only near resonance with various exciton states are analyzed, and the modes are assigned. The resonance profiles of the Raman peaks reflect the joint density of states for optical transitions, but the symmetry of the exciton wave functions leads to selective enhancement of the A1g mode at the A exciton energy and the shear mode at the C exciton energy. We also find Davydov splitting of intralayer A1g, E1g, and A2u modes due to interlayer interaction for some excitation energies near resonances. Furthermore, by fitting the spectral positions of interlayer shear and breathing modes and Davydov splitting of intralayer modes to a linear chain model, we extract the strength of the interlayer interaction. We find that the second-nearest-neighbor interlayer interaction amounts to about 30% of the nearest-neighbor interaction for both in-plane and out-of-plane vibrations.
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Affiliation(s)
- Kangwon Kim
- Department of Physics, Sogang University , Seoul 04107, Korea
| | - Jae-Ung Lee
- Department of Physics, Sogang University , Seoul 04107, Korea
| | - Dahyun Nam
- Department of Physics, Sogang University , Seoul 04107, Korea
| | - Hyeonsik Cheong
- Department of Physics, Sogang University , Seoul 04107, Korea
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50
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Tran TT, Elbadawi C, Totonjian D, Lobo CJ, Grosso G, Moon H, Englund DR, Ford MJ, Aharonovich I, Toth M. Robust Multicolor Single Photon Emission from Point Defects in Hexagonal Boron Nitride. ACS NANO 2016; 10:7331-8. [PMID: 27399936 DOI: 10.1021/acsnano.6b03602] [Citation(s) in RCA: 160] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Hexagonal boron nitride (hBN) is an emerging two-dimensional material for quantum photonics owing to its large bandgap and hyperbolic properties. Here we report two approaches for engineering quantum emitters in hBN multilayers using either electron beam irradiation or annealing and characterize their photophysical properties. The defects exhibit a broad range of multicolor room-temperature single photon emissions across the visible and the near-infrared spectral ranges, narrow line widths of sub-10 nm at room temperature, and a short excited-state lifetime, and high brightness. We show that the emitters can be categorized into two general groups, but most likely possess similar crystallographic structure. Remarkably, the emitters are extremely robust and withstand aggressive annealing treatments in oxidizing and reducing environments. Our results constitute a step toward deterministic engineering of single emitters in 2D materials and hold great promise for the use of defects in boron nitride as sources for quantum information processing and nanophotonics.
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Affiliation(s)
- Toan Trong Tran
- School of Mathematical and Physical Sciences, University of Technology Sydney , Ultimo, New South Wales 2007, Australia
| | - Christopher Elbadawi
- School of Mathematical and Physical Sciences, University of Technology Sydney , Ultimo, New South Wales 2007, Australia
| | - Daniel Totonjian
- School of Mathematical and Physical Sciences, University of Technology Sydney , Ultimo, New South Wales 2007, Australia
| | - Charlene J Lobo
- School of Mathematical and Physical Sciences, University of Technology Sydney , Ultimo, New South Wales 2007, Australia
| | - Gabriele Grosso
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Hyowon Moon
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Dirk R Englund
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Michael J Ford
- School of Mathematical and Physical Sciences, University of Technology Sydney , Ultimo, New South Wales 2007, Australia
| | - Igor Aharonovich
- School of Mathematical and Physical Sciences, University of Technology Sydney , Ultimo, New South Wales 2007, Australia
| | - Milos Toth
- School of Mathematical and Physical Sciences, University of Technology Sydney , Ultimo, New South Wales 2007, Australia
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