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Xie X, Li S, Chen J, Ding J, He J, Liu Z, Wang JT, Liu Y. Tunable Valley Pseudospin and Electron-Phonon Coupling in WSe 2/1T-VSe 2 Heterostructures. ACS APPLIED MATERIALS & INTERFACES 2024. [PMID: 39298334 DOI: 10.1021/acsami.4c11399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/21/2024]
Abstract
Heterostructure engineering provides versatile platforms for exploring exotic physics and enhancing the device performance through interface coupling. Despite the rich array of physical phenomena presented by heterostructures composed of semiconductor and metal van der Waals materials, significant gaps remain in understanding their optical, thermal, and electronic properties. Here, we demonstrate that the valley pseudospin and electron-phonon coupling in monolayer WSe2 are significantly influenced by interface coupling with 1T-VSe2. The heterointerface alters the relaxation process of valley excitons, leading to a transition in magnetic-field-dependent valley polarization from a linear to a "V" shape. Furthermore, we uncover that enhanced electron-phonon coupling exacerbates variations in exciton and valley exciton behavior with temperature, involving higher phonon energies and a shift from acoustic to optical phonons. These findings highlight a promising pathway to manipulate valley excitons and investigate electron-phonon coupling through van der Waals interface interactions.
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Affiliation(s)
- Xing Xie
- Institute of Quantum Physics, School of Physics, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
- State Key Laboratory of Precision Manufacturing for Extreme Service Performance, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
| | - Shaofei Li
- Institute of Quantum Physics, School of Physics, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
| | - Junying Chen
- Institute of Quantum Physics, School of Physics, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
- State Key Laboratory of Precision Manufacturing for Extreme Service Performance, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
| | - Junnan Ding
- Institute of Quantum Physics, School of Physics, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
- State Key Laboratory of Precision Manufacturing for Extreme Service Performance, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
| | - Jun He
- Institute of Quantum Physics, School of Physics, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
| | - Zongwen Liu
- School of Chemical and Biomolecular Engineering, the University of Sydney, Sydney, New South Wales 2006, Australia
- The University of Sydney Nano Institute, the University of Sydney, Sydney, New South Wales 2006, Australia
| | - Jian-Tao Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, People's Republic of China
| | - Yanping Liu
- Institute of Quantum Physics, School of Physics, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
- State Key Laboratory of Precision Manufacturing for Extreme Service Performance, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China
- Shenzhen Research Institute of Central South University, Shenzhen 518000, People's Republic of China
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2
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Li J, Chen YQ, Yuan HK, Tian CL. Prediction of the two-dimensional ferromagnetic semiconductor Janus 2H-ZrTeI monolayer with large valley and piezoelectric polarizations. NANOSCALE 2024. [PMID: 39267610 DOI: 10.1039/d4nr01692k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/17/2024]
Abstract
Two-dimensional room-temperature Janus ferrovalley semiconductors with valley polarization and piezoelectric polarization offer new perspectives for designing multifunctional nanodevices. Herein, using first-principles calculations, we predict that the Janus 2H-ZrTeI monolayer is an intrinsic ferromagnetic semiconductor with in-plane magnetic anisotropy and a Curie temperature of 111 K. The Janus ZrTeI monolayer possesses a significant valley polarization of 141 meV due to time-reversal and inversion symmetry breaking. Based on the valley-contrasting Berry curvature, the anomalous valley Hall effect can be observed under an in-plane electric field. Meanwhile, the breaking of the inversion symmetry and mirror symmetry results in large longitudinal and transverse piezoelectric coefficients. By applying biaxial strain, the Janus 2H-ZrTeI monolayer can also be transformed into a Weyl nodal line semimetal. Furthermore, bilayers of ZrTeI with AB and BA stacking configurations allow the coexistence of valley polarization and ferroelectricity, enabling the manipulation of magnetism, ferroelectric polarization, and valley polarization through interlayer sliding. Our work provides a platform for studying valley polarization, piezoelectricity, and multiferroic coupling, which is significant for the application of multifunctional devices.
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Affiliation(s)
- Jie Li
- School of Physical Science and Technology, Southwest University, Chongqing 400715, China.
| | - Ya-Qing Chen
- School of Physical Science and Technology, Southwest University, Chongqing 400715, China.
| | - Hong-Kuan Yuan
- School of Physical Science and Technology, Southwest University, Chongqing 400715, China.
| | - Chun-Ling Tian
- School of Physical Science and Technology, Southwest University, Chongqing 400715, China.
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3
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Liu H, Wu Y, Wu Z, Liu S, Zhang VL, Yu T. Coexisting Phases in Transition Metal Dichalcogenides: Overview, Synthesis, Applications, and Prospects. ACS NANO 2024; 18:2708-2729. [PMID: 38252696 DOI: 10.1021/acsnano.3c10665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Over the past decade, significant advancements have been made in phase engineering of two-dimensional transition metal dichalcogenides (TMDCs), thereby allowing controlled synthesis of various phases of TMDCs and facile conversion between them. Recently, there has been emerging interest in TMDC coexisting phases, which contain multiple phases within one nanostructured TMDC. By taking advantage of the merits from the component phases, the coexisting phases offer enhanced performance in many aspects compared with single-phase TMDCs. Herein, this review article thoroughly expounds the latest progress and ongoing efforts on the syntheses, properties, and applications of TMDC coexisting phases. The introduction section overviews the main phases of TMDCs (2H, 3R, 1T, 1T', 1Td), along with the advantages of phase coexistence. The subsequent section focuses on the synthesis methods for coexisting phases of TMDCs, with particular attention to local patterning and random formations. Furthermore, on the basis of the versatile properties of TMDC coexisting phases, their applications in magnetism, valleytronics, field-effect transistors, memristors, and catalysis are discussed. Lastly, a perspective is presented on the future development, challenges, and potential opportunities of TMDC coexisting phases. This review aims to provide insights into the phase engineering of 2D materials for both scientific and engineering communities and contribute to further advancements in this emerging field.
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Affiliation(s)
- Haiyang Liu
- School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Yaping Wu
- School of Physics and Technology, Xiamen University, Xiamen 361005, China
| | - Zhiming Wu
- School of Physics and Technology, Xiamen University, Xiamen 361005, China
| | - Sheng Liu
- School of Physics and Technology, Wuhan University, Wuhan 430072, China
- Wuhan Institute of Quantum Technology, Wuhan 430206, China
| | - Vanessa Li Zhang
- School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Ting Yu
- School of Physics and Technology, Wuhan University, Wuhan 430072, China
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4
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Wang F, Zhang T, Xie R, Liu A, Dai F, Chen Y, Xu T, Wang H, Wang Z, Liao L, Wang J, Zhou P, Hu W. Next-Generation Photodetectors beyond Van Der Waals Junctions. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2301197. [PMID: 36960667 DOI: 10.1002/adma.202301197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/16/2023] [Indexed: 06/18/2023]
Abstract
With the continuous advancement of nanofabrication techniques, development of novel materials, and discovery of useful manipulation mechanisms in high-performance applications, especially photodetectors, the morphology of junction devices and the way junction devices are used are fundamentally revolutionized. Simultaneously, new types of photodetectors that do not rely on any junction, providing a high signal-to-noise ratio and multidimensional modulation, have also emerged. This review outlines a unique category of material systems supporting novel junction devices for high-performance detection, namely, the van der Waals materials, and systematically discusses new trends in the development of various types of devices beyond junctions. This field is far from mature and there are numerous methods to measure and evaluate photodetectors. Therefore, it is also aimed to provide a solution from the perspective of applications in this review. Finally, based on the insight into the unique properties of the material systems and the underlying microscopic mechanisms, emerging trends in junction devices are discussed, a new morphology of photodetectors is proposed, and some potential innovative directions in the subject area are suggested.
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Affiliation(s)
- Fang Wang
- State Key Laboratory of Infrared Physics, Chinese Academy of Sciences, Shanghai, 200083, China
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Tao Zhang
- State Key Laboratory of Infrared Physics, Chinese Academy of Sciences, Shanghai, 200083, China
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Runzhang Xie
- State Key Laboratory of Infrared Physics, Chinese Academy of Sciences, Shanghai, 200083, China
| | - Anna Liu
- State Key Laboratory of Infrared Physics, Chinese Academy of Sciences, Shanghai, 200083, China
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Fuxing Dai
- State Key Laboratory of Infrared Physics, Chinese Academy of Sciences, Shanghai, 200083, China
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yue Chen
- State Key Laboratory of Infrared Physics, Chinese Academy of Sciences, Shanghai, 200083, China
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Tengfei Xu
- School of Microelectronics, Frontier Institute of Chip and System, Fudan University, Shanghai, 200433, China
| | - Hailu Wang
- State Key Laboratory of Infrared Physics, Chinese Academy of Sciences, Shanghai, 200083, China
| | - Zhen Wang
- State Key Laboratory of Infrared Physics, Chinese Academy of Sciences, Shanghai, 200083, China
| | - Lei Liao
- College of Semiconductors (College of Integrated Circuits), Hunan University, Changsha, 410082, China
| | - Jianlu Wang
- School of Microelectronics, Frontier Institute of Chip and System, Fudan University, Shanghai, 200433, China
| | - Peng Zhou
- School of Microelectronics, Frontier Institute of Chip and System, Fudan University, Shanghai, 200433, China
| | - Weida Hu
- State Key Laboratory of Infrared Physics, Chinese Academy of Sciences, Shanghai, 200083, China
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
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5
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Ma X, Fan Y, Li W, Li Y, Liu X, Zhao X, Zhao M. Valley manipulation by sliding-induced tuning of the magnetic proximity effect in heterostructures. NANOSCALE 2023; 15:18678-18686. [PMID: 37933460 DOI: 10.1039/d3nr03086e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2023]
Abstract
Spontaneous valley polarization, resulting from the magnetic proximity effect, holds tremendous potential for information processing and storage. This effect is highly sensitive to the interfacial electronic properties, encompassing both charge transitions and spin configurations. In this study, we propose the manipulation of valley splitting by leveraging the tunable magnetic proximity effect through sliding an inversion-symmetric antiferromagnetic (AFM-I) monolayer within a TMD/AFM-I/TMD heterostructure. The presence of the antiferromagnetic monolayer enhances the robustness of the magnetic order during interlayer sliding. Notably, we demonstrate that the polarized stacking of the heterostructure enables the generation of intrinsic out-of-plane and in-plane electric polarization. Intriguingly, interlayer sliding not only reverses the out-of-plane and in-plane electric polarization but also alters the layer-resolved valley splitting, thereby contributing to the emergence of the anomalous valley Hall effect and the layer Hall effect. In addition, the manipulation of valleys remains consistent with both the valley optical selection rules and the intra/interlayer emission energy, which are contingent upon the interlayer sliding. The findings of this work hold promise for potential applications in the field of valleytronics.
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Affiliation(s)
- Xikui Ma
- Center for Optics Research and Engineering of Shandong University, Shandong University, Qingdao, 266237, China.
| | - Yingcai Fan
- School of Physics, Shandong University, Jinan, Shandong, 250100, China.
| | - Weifeng Li
- School of Physics, Shandong University, Jinan, Shandong, 250100, China.
| | - Yangyang Li
- School of Physics, Shandong University, Jinan, Shandong, 250100, China.
| | - Xiangdong Liu
- School of Physics, Shandong University, Jinan, Shandong, 250100, China.
| | - Xian Zhao
- Center for Optics Research and Engineering of Shandong University, Shandong University, Qingdao, 266237, China.
| | - Mingwen Zhao
- School of Physics, Shandong University, Jinan, Shandong, 250100, China.
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6
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Lubert-Perquel D, Acharya S, Johnson JC. Optically Addressing Exciton Spin and Pseudospin in Nanomaterials for Spintronics Applications. ACS APPLIED OPTICAL MATERIALS 2023; 1:1742-1760. [PMID: 38037653 PMCID: PMC10683369 DOI: 10.1021/acsaom.3c00299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 10/26/2023] [Accepted: 10/26/2023] [Indexed: 12/02/2023]
Abstract
Oriented exciton spins that can be generated and manipulated optically are of interest for a range of applications, including spintronics, quantum information science, and neuromorphic computing architectures. Although materials that host such excitons often lack practical coherence times for use on their own, strategic transduction of the magnetic information across interfaces can combine fast modulation with longer-term storage and readout. Several nanostructure systems have been put forward due to their interesting magneto-optical properties and their possible manipulation using circularly polarized light. These material systems are presented here, namely two-dimensional (2D) systems due to the unique spin-valley coupling properties and quantum dots for their exciton fine structure. 2D magnets are also discussed for their anisotropic spin behavior and extensive 2D magnetic states that are not yet fully understood but could pave the way for emergent techniques of magnetic control. This review also details the experimental and theoretical tools to measure and understand these systems along with a discussion on the progress of optical manipulation of spins and magnetic order transitions.
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Affiliation(s)
- Daphné Lubert-Perquel
- Materials, Chemical, and
Computational Science Directorate, National
Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
| | - Swagata Acharya
- Materials, Chemical, and
Computational Science Directorate, National
Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
| | - Justin C. Johnson
- Materials, Chemical, and
Computational Science Directorate, National
Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
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7
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Lau CS, Das S, Verzhbitskiy IA, Huang D, Zhang Y, Talha-Dean T, Fu W, Venkatakrishnarao D, Johnson Goh KE. Dielectrics for Two-Dimensional Transition-Metal Dichalcogenide Applications. ACS NANO 2023. [PMID: 37257134 DOI: 10.1021/acsnano.3c03455] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Despite over a decade of intense research efforts, the full potential of two-dimensional transition-metal dichalcogenides continues to be limited by major challenges. The lack of compatible and scalable dielectric materials and integration techniques restrict device performances and their commercial applications. Conventional dielectric integration techniques for bulk semiconductors are difficult to adapt for atomically thin two-dimensional materials. This review provides a brief introduction into various common and emerging dielectric synthesis and integration techniques and discusses their applicability for 2D transition metal dichalcogenides. Dielectric integration for various applications is reviewed in subsequent sections including nanoelectronics, optoelectronics, flexible electronics, valleytronics, biosensing, quantum information processing, and quantum sensing. For each application, we introduce basic device working principles, discuss the specific dielectric requirements, review current progress, present key challenges, and offer insights into future prospects and opportunities.
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Affiliation(s)
- Chit Siong Lau
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Republic of Singapore
| | - Sarthak Das
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Republic of Singapore
| | - Ivan A Verzhbitskiy
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Republic of Singapore
| | - Ding Huang
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Republic of Singapore
| | - Yiyu Zhang
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Republic of Singapore
| | - Teymour Talha-Dean
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Republic of Singapore
- Department of Physics and Astronomy, Queen Mary University of London, London E1 4NS, United Kingdom
| | - Wei Fu
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Republic of Singapore
| | - Dasari Venkatakrishnarao
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Republic of Singapore
| | - Kuan Eng Johnson Goh
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Republic of Singapore
- Department of Physics, National University of Singapore, 2 Science Drive 3, 117551, Singapore
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 50 Nanyang Avenue 639798, Singapore
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8
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Babar ZUD, Raza A, Cassinese A, Iannotti V. Two Dimensional Heterostructures for Optoelectronics: Current Status and Future Perspective. Molecules 2023; 28:2275. [PMID: 36903520 PMCID: PMC10005545 DOI: 10.3390/molecules28052275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 02/05/2023] [Accepted: 02/16/2023] [Indexed: 03/05/2023] Open
Abstract
Researchers have found various families of two-dimensional (2D) materials and associated heterostructures through detailed theoretical work and experimental efforts. Such primitive studies provide a framework to investigate novel physical/chemical characteristics and technological aspects from micro to nano and pico scale. Two-dimensional van der Waals (vdW) materials and their heterostructures can be obtained to enable high-frequency broadband through a sophisticated combination of stacking order, orientation, and interlayer interactions. These heterostructures have been the focus of much recent research due to their potential applications in optoelectronics. Growing the layers of one kind of 2D material over the other, controlling absorption spectra via external bias, and external doping proposes an additional degree of freedom to modulate the properties of such materials. This mini review focuses on current state-of-the-art material design, manufacturing techniques, and strategies to design novel heterostructures. In addition to a discussion of fabrication techniques, it includes a comprehensive analysis of the electrical and optical properties of vdW heterostructures (vdWHs), particularly emphasizing the energy-band alignment. In the following sections, we discuss specific optoelectronic devices, such as light-emitting diodes (LEDs), photovoltaics, acoustic cavities, and biomedical photodetectors. Furthermore, this also includes a discussion of four different 2D-based photodetector configurations according to their stacking order. Moreover, we discuss the challenges that remain to be addressed in order to realize the full potential of these materials for optoelectronics applications. Finally, as future perspectives, we present some key directions and express our subjective assessment of upcoming trends in the field.
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Affiliation(s)
- Zaheer Ud Din Babar
- Scuola Superiore Meridionale (SSM), University of Naples Federico II, Largo S. Marcellino 10, 80138 Naples, Italy
- Department of Physics “Ettore Pancini”, University of Naples Federico II, Piazzale Tecchio 80, 80125 Naples, Italy
| | - Ali Raza
- Department of Physics “Ettore Pancini”, University of Naples Federico II, Piazzale Tecchio 80, 80125 Naples, Italy
| | - Antonio Cassinese
- Department of Physics “Ettore Pancini”, University of Naples Federico II, Piazzale Tecchio 80, 80125 Naples, Italy
- CNR–SPIN (Institute for Superconductors, Oxides and Other Innovative Materials and Devices), Piazzale V. Tecchio 80, 80125 Naples, Italy
| | - Vincenzo Iannotti
- Department of Physics “Ettore Pancini”, University of Naples Federico II, Piazzale Tecchio 80, 80125 Naples, Italy
- CNR–SPIN (Institute for Superconductors, Oxides and Other Innovative Materials and Devices), Piazzale V. Tecchio 80, 80125 Naples, Italy
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9
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Han Z, Hao H, Zheng X, Zeng Z. Bipolar spin-filtering and giant magnetoresistance effect in spin-semiconducting zigzag graphene nanoribbons. Phys Chem Chem Phys 2023; 25:6461-6466. [PMID: 36779977 DOI: 10.1039/d2cp05834k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Spintronics is one of the main topics in condensed matter physics, in which half-metallicity and giant magnetoresistance are two important objects to achieve. In this work, we study the spin dependent transport properties of zigzag graphene nanoribbons (ZGNR) with asymmetric edge hydrogenation and different magnetic configurations using the non-equilibrium Green's function method combined with density functional calculations. Our results show that when the magnetic configurations of the electrodes change from parallel to antiparallel, the currents in the tunnel junction change substantially, resulting in a high conductance state and a low conductance state, with the tunnel magnetoresistance (TMR) ratio larger than 1 × 105% achieved. In addition, in the parallel magnetic configurations, an ideal bipolar spin filtering effect is observed, making it flexible to switch the spin polarity of current by reversing the bias direction. All these features originate from the spin semiconducting behavior of the asymmetrically hydrogenated ZGNRs. The findings suggest that asymmetric edge hydrogenation provides an important way to construct multi-functional spintronic devices with ZGNRs.
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Affiliation(s)
- Ziqi Han
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei, 230031, China.,Science Island Branch of Graduate School, University of Science and Technology of China, Hefei, 230026, China.,College of Information Science and Technology, Nanjing Forestry University, Nanjing, 210037, China.
| | - Hua Hao
- School of Physics, Hangzhou Normal University, Hangzhou, 311121, China
| | - Xiaohong Zheng
- Science Island Branch of Graduate School, University of Science and Technology of China, Hefei, 230026, China.,College of Information Science and Technology, Nanjing Forestry University, Nanjing, 210037, China.
| | - Zhi Zeng
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei, 230031, China.,Science Island Branch of Graduate School, University of Science and Technology of China, Hefei, 230026, China
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10
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Peng M, Cheng J, Zheng X, Ma J, Feng Z, Sun X. 2D-materials-integrated optoelectromechanics: recent progress and future perspectives. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2023; 86:026402. [PMID: 36167057 DOI: 10.1088/1361-6633/ac953e] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 09/27/2022] [Indexed: 06/16/2023]
Abstract
The discovery of two-dimensional (2D) materials has gained worldwide attention owing to their extraordinary optical, electrical, and mechanical properties. Due to their atomic layer thicknesses, the emerging 2D materials have great advantages of enhanced interaction strength, broad operating bandwidth, and ultralow power consumption for optoelectromechanical coupling. The van der Waals (vdW) epitaxy or multidimensional integration of 2D material family provides a promising platform for on-chip advanced nano-optoelectromechanical systems (NOEMS). Here, we provide a comprehensive review on the nanomechanical properties of 2D materials and the recent advances of 2D-materials-integrated nano-electromechanical systems and nano-optomechanical systems. By utilizing active nanophotonics and optoelectronics as the interface, 2D active NOEMS and their coupling effects are particularly highlighted at the 2D atomic scale. Finally, we share our viewpoints on the future perspectives and key challenges of scalable 2D-materials-integrated active NOEMS for on-chip miniaturized, lightweight, and multifunctional integration applications.
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Affiliation(s)
- Mingzeng Peng
- Beijing Key Laboratory for Magneto-Photoelectrical Composite and Interface Science, School of Mathematics and Physics, University of Science and Technology Beijing, Beijing 100083,People's Republic of China
- Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong Special Administrative Region of China
| | - Jiadong Cheng
- Beijing Key Laboratory for Magneto-Photoelectrical Composite and Interface Science, School of Mathematics and Physics, University of Science and Technology Beijing, Beijing 100083,People's Republic of China
| | - Xinhe Zheng
- Beijing Key Laboratory for Magneto-Photoelectrical Composite and Interface Science, School of Mathematics and Physics, University of Science and Technology Beijing, Beijing 100083,People's Republic of China
| | - Jingwen Ma
- Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong Special Administrative Region of China
| | - Ziyao Feng
- Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong Special Administrative Region of China
| | - Xiankai Sun
- Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong Special Administrative Region of China
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11
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Wang X, Niu G, Jiang J, Sui L, Zeng X, Liu X, Zhang Y, Wu G, Yuan K, Yang X. Anomalous Dynamics of Defect-Assisted Phonon Recycling in Few-Layer Mo 0.5W 0.5S 2. J Phys Chem Lett 2022; 13:10395-10403. [PMID: 36318176 DOI: 10.1021/acs.jpclett.2c02935] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Alloying has emerged as a new strategy to tune the function of 2D transition metal dichalcogenides (TMDCs). However, the lack of research on the electrical and structural properties of these alloys limits their practical applications. Here, femtosecond transient absorption spectroscopy with pump pulse tunability is performed to elucidate the ultrafast carrier dynamics in the few-layer Mo0.5W0.5S2 prepared by the liquid phase exfoliation method. An anomalous rebleaching of the ground state is observed at high pump fluence by 3.1 eV excitation. We ascribe this rebleaching of the ground state to the mechanism that the carriers trapped in the defect are thermally excited back to the untrapped exciton state due to the phonon recycling, which hinders the dissipation of nonradiative energy, through comparative experiments and global analysis. Our findings demonstrate a novel energy transfer channel assisted by defect in few-layer TMDCs which is critical for their advanced applications.
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Affiliation(s)
- Xiaowei Wang
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- University of the Chinese Academy of Sciences, Beijing 100039, China
| | - Guangming Niu
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- Marine Engineering College, Dalian Maritime University, Dalian 116026, China
| | - Jutao Jiang
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- University of the Chinese Academy of Sciences, Beijing 100039, China
| | - Laizhi Sui
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Xiangyu Zeng
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China
| | - Xin Liu
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- Science College, Dalian Maritime University, Dalian 116026, China
| | - Yutong Zhang
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Guorong Wu
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Kaijun Yuan
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- Department of Chemistry, College of Science, Southern University of Science and Technology, Shenzhen 518055, China
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12
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Shi Y, Jia N, Cai J, Lyu Z, Liu Z. 2D electrene LaH 2monolayer: an ideal ferrovalley direct semiconductor with room-temperature ferromagnetic stability. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:475303. [PMID: 36179704 DOI: 10.1088/1361-648x/ac96bb] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Accepted: 09/30/2022] [Indexed: 06/16/2023]
Abstract
In developing nonvolatile valleytronic devices, ferromagnetic (FM) ferrovalley semiconductors are critically needed due to the existence of spontaneous valley polarization. At present, however, the known real materials have various drawbacks towards practical applications, including the in-plane FM ground state, low Curie temperature (TC), small valley polarization, narrow energy window with clean polarized valley, and indirect bandgap. From first-principles calculations, here we predict anideal ferrovalley semiconductor, honeycomb LaH2monolayer (ML), whose intrinsic properties can overcome all these shortcomings. We demonstrate that LaH2ML, having satisfied structural stability, is a FM half-semiconducting electrene (La3+2H-⋅e-) with its magnetic moments localized at the lattice interstitial sites rather than La atoms. At the same time, LaH2ML holds the following desired attributes: a robust out-of-plane FM ground state with a highTC(334 K), a sizable valley polarization (166 meV), a wide energy window (137 meV) harboring clean single-valley carriers, and a direct bandgap. These results identify a much needed ideal ferrovalley semiconductor candidate, holding the promising application potential in valleytronics and spintronics devices.
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Affiliation(s)
- Yongting Shi
- School of Physical Science and Technology, Inner Mongolia University, Hohhot 010021, People's Republic of China
| | - Ningning Jia
- School of Physical Science and Technology, Inner Mongolia University, Hohhot 010021, People's Republic of China
| | - Jiangtao Cai
- Department of Physics, Shaanxi University of Science and Technology, Xi'an 710021, People's Republic of China
| | - Zhiheng Lyu
- School of Physical Science and Technology, Inner Mongolia University, Hohhot 010021, People's Republic of China
| | - Zhifeng Liu
- School of Physical Science and Technology, Inner Mongolia University, Hohhot 010021, People's Republic of China
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13
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Li JX, Li WQ, Hung SH, Chen PL, Yang YC, Chang TY, Chiu PW, Jeng HT, Liu CH. Electric control of valley polarization in monolayer WSe 2 using a van der Waals magnet. NATURE NANOTECHNOLOGY 2022; 17:721-728. [PMID: 35501377 DOI: 10.1038/s41565-022-01115-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 03/07/2022] [Indexed: 06/14/2023]
Abstract
Electrical manipulation of the valley degree of freedom in transition metal dichalcogenides is central to developing valleytronics. Towards this end, ferromagnetic contacts, such as Ga(Mn)As and permalloy, have been exploited to inject spin-polarized carriers into transition metal dichalcogenides to realize valley-dependent polarization. However, these materials require either a high external magnetic field or complicated epitaxial growth steps, limiting their practical applications. Here we report van der Waals heterostructures based on a monolayer WSe2 and an Fe3GeTe2/hexagonal boron nitride ferromagnetic tunnelling contact that under a bias voltage can effectively inject spin-polarized holes into WSe2, leading to a population imbalance between ±K valleys, as confirmed by density functional theory calculations and helicity-dependent electroluminescence measurements. Under an external magnetic field, we observe that the helicity of electroluminescence flips its sign and exhibits a hysteresis loop in agreement with the magnetic hysteresis loop obtained from reflective magnetic circular dichroism characterizations on Fe3GeTe2. Our results could address key challenges of valleytronics and prove promising for van der Waals magnets for magneto-optoelectronics applications.
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Affiliation(s)
- Jia-Xin Li
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu, Taiwan
| | - Wei-Qing Li
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu, Taiwan
| | - Sheng-Hsiung Hung
- Department of Physics, National Tsing Hua University, Hsinchu, Taiwan
| | - Po-Liang Chen
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu, Taiwan
| | - Yueh-Chiang Yang
- Department of Electrical Engineering, National Tsing Hua University, Hsinchu, Taiwan
| | - Tian-Yun Chang
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu, Taiwan
| | - Po-Wen Chiu
- Department of Electrical Engineering, National Tsing Hua University, Hsinchu, Taiwan
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan
| | - Horng-Tay Jeng
- Department of Physics, National Tsing Hua University, Hsinchu, Taiwan.
- Institute of Physics, Academia Sinica, Taipei, Taiwan.
- Physics Division, National Center for Theoretical Sciences, Hsinchu, Taiwan.
| | - Chang-Hua Liu
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu, Taiwan.
- Department of Electrical Engineering, National Tsing Hua University, Hsinchu, Taiwan.
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14
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Jalouli A, Kilinc M, Marga A, Bian M, Thomay T, Petrou A, Zeng H. Transition metal dichalcogenide graded alloy monolayers by chemical vapor deposition and comparison to 2D Ising model. J Chem Phys 2022; 156:134704. [PMID: 35395886 DOI: 10.1063/5.0081929] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In this work, a chemical vapor deposition (CVD) method was developed for the synthesis of transition metal dichalcogenide alloy monolayers, with a composition gradient in the radial direction. The composition gradient was achieved by controlling the substrate cooling rate during the CVD growth. The two types of alloys, namely, WS2(1-x)Se2x and MoS2(1-x)Se2x, were found to exhibit an opposite composition gradient. This is attributed to their different cohesive energies. A two-dimensional Ising model is used to explain the growth mechanism, where two ends of the composition were modeled as a magnetically ordered phase and a paramagnetic phase. The composition as a function of substrate temperature is then represented by the thermal magnetization curve.
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Affiliation(s)
- Alireza Jalouli
- Department of Physics, University at Buffalo, The State University of New York, Buffalo, New York 14260, USA
| | - Muhammed Kilinc
- Department of Physics, University at Buffalo, The State University of New York, Buffalo, New York 14260, USA
| | - Austin Marga
- Department of Physics, University at Buffalo, The State University of New York, Buffalo, New York 14260, USA
| | - Mengying Bian
- Department of Physics, University at Buffalo, The State University of New York, Buffalo, New York 14260, USA
| | - Tim Thomay
- Department of Physics, University at Buffalo, The State University of New York, Buffalo, New York 14260, USA
| | - Athos Petrou
- Department of Physics, University at Buffalo, The State University of New York, Buffalo, New York 14260, USA
| | - Hao Zeng
- Department of Physics, University at Buffalo, The State University of New York, Buffalo, New York 14260, USA
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15
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Sheng K, Yuan HK, Wang ZY. Monolayer gadolinium halides, GdX 2 (X = F, Cl, Br): intrinsic ferrovalley materials with spontaneous spin and valley polarizations. Phys Chem Chem Phys 2022; 24:3865-3874. [PMID: 35088778 DOI: 10.1039/d1cp05097d] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two-dimensional (2D) intrinsic ferrovalley semiconductors provide unprecedented opportunities to investigate valley physics as well as providing promising device applications due to their exceptional combination of spontaneous spin and valley polarizations. Here, we have predicted from first-principles calculations and Monte Carlo simulations that monolayers (MLs) GdX2 are such extremely rare excellent materials. Apart from their robust stabilities energetically, dynamically, thermally, and mechanically, these 2D materials are found to be semiconducting intrinsic ferromagnets where the magnetic coupling is ascribed to 5d-electron-mediated 4f-4f exchange interactions. Moreover, MLs GdX2 (X = F, Cl, Br) not only exhibit significant magnetic anisotropy energy of 351, 268, and 30 μeV per Gd, but also have a high Curie temperature of 300, 245, and 225 K, respectively. In particular, spontaneous valley polarization in three systems occurs due to the cooperative interplay between the spin-orbit coupling and magnetic exchange interactions, whose magnitude is as sizable as 55, 38, and 82 meV for MLs GdF2, GdCl2, and GdBr2, respectively. Under the action of an in-plane longitudinal electrical field, the valley-contrasting Berry curvatures arising from the broken space-inversion and time-reversal symmetries in MLs GdX2 could yield opposite transverse velocities of the carriers, giving rise to the occurrence of a spin-polarized anomalous valley Hall effect. Overall, these findings render 2D GdX2 a class of promising candidate materials for experimental studies and practical spintronics and valleytronics applications.
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Affiliation(s)
- Kang Sheng
- School of Physical Science and Technology, Southwest University, Chongqing 400715, China.
| | - Hong-Kuan Yuan
- School of Physical Science and Technology, Southwest University, Chongqing 400715, China.
| | - Zhi-Yong Wang
- School of Physical Science and Technology, Southwest University, Chongqing 400715, China.
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16
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Liu Y, Zhang T, Dou K, Du W, Peng R, Dai Y, Huang B, Ma Y. Valley-Contrasting Physics in Single-Layer CrSi 2N 4 and CrSi 2P 4. J Phys Chem Lett 2021; 12:8341-8346. [PMID: 34431679 DOI: 10.1021/acs.jpclett.1c02069] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The exploration of valley-contrasting physics in two-dimensional materials with strong spin-orbit coupling is of great significance for both fundamental physics and advanced information technology. Here, using first-principles calculations, we report the identification of promising valley-contrasting physics in single-layer CrSi2N4 and CrSi2P4. Single-layer CrSi2N4 and CrSi2P4 are semiconductors with a direct band gap locating at the K/K' point, which forms a pair of degenerate but nonequivalent valleys in both the conduction and valence bands. These valleys display the intriguing valley spin splitting when considering spin-orbit coupling. Particularly for the valence bands, the valley spin splitting can reach up to 0.13/0.17 eV, giving rise to the robust spin-valley coupling and thus the coexistence of spin and valley Hall effects. The underlying physics are uncovered in detail. Moreover, strain is demonstrated to be an effective way for manipulating their coupled spin and valley physics.
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Affiliation(s)
- Yibo Liu
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Shandanan Street 27, Jinan 250100, China
| | - Ting Zhang
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Shandanan Street 27, Jinan 250100, China
| | - Kaiying Dou
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Shandanan Street 27, Jinan 250100, China
| | - Wenhui Du
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Shandanan Street 27, Jinan 250100, China
| | - Rui Peng
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Shandanan Street 27, Jinan 250100, China
| | - Ying Dai
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Shandanan Street 27, Jinan 250100, China
| | - Baibiao Huang
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Shandanan Street 27, Jinan 250100, China
| | - Yandong Ma
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Shandanan Street 27, Jinan 250100, China
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17
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Ou H, Matsuoka H, Tempia J, Yamada T, Takahashi T, Oi K, Takaguchi Y, Endo T, Miyata Y, Chen CH, Li LJ, Pu J, Takenobu T. Spatial Control of Dynamic p-i-n Junctions in Transition Metal Dichalcogenide Light-Emitting Devices. ACS NANO 2021; 15:12911-12921. [PMID: 34309369 DOI: 10.1021/acsnano.1c01242] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Emerging transition metal dichalcogenides (TMDCs) offer an attractive platform for investigating functional light-emitting devices, such as flexible devices, quantum and chiral devices, high-performance optical modulators, and ultralow threshold lasers. In these devices, the key operation is to control the light-emitting position, that is, the spatial position of the recombination zone to generate electroluminescence, which permits precise light guides/passes/confinement to ensure favorable device performance. Although various structures of TMDC light-emitting devices have been demonstrated, including the transistor configuration and heterostructured diodes, it is still difficult to tune the light-emitting position precisely owing to the structural device complexity. In this study, we fabricated two-terminal light-emitting devices with chemically synthesized WSe2, MoSe2, and WS2 monolayers, and performed direct observations of their electroluminescence, from which we discovered a divergence in their light-emitting positions. Subsequently, we propose a method to associate spatial electroluminescence imaging with transport properties among different samples; consequently, a common rule for determining the locations of recombination zones is revealed. Owing to dynamic carrier accumulations and p-i-n junction formations, the light-emitting positions in electrolyte-based devices can be tuned continuously. The proposed method will expand the device applicability for designing functional optoelectronic applications based on TMDCs.
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Affiliation(s)
- Hao Ou
- Department of Applied Physics, Nagoya University, Nagoya 464-8603, Japan
| | - Hirofumi Matsuoka
- Department of Applied Physics, Nagoya University, Nagoya 464-8603, Japan
| | - Juliette Tempia
- Department of Applied Physics, Nagoya University, Nagoya 464-8603, Japan
| | - Tomoyuki Yamada
- Department of Applied Physics, Nagoya University, Nagoya 464-8603, Japan
| | - Togo Takahashi
- Department of Applied Physics, Nagoya University, Nagoya 464-8603, Japan
| | - Koshi Oi
- Department of Applied Physics, Nagoya University, Nagoya 464-8603, Japan
| | - Yuhei Takaguchi
- Department of Physics, Tokyo Metropolitan University, Tokyo 192-0397, Japan
| | - Takahiko Endo
- Department of Physics, Tokyo Metropolitan University, Tokyo 192-0397, Japan
| | - Yasumitsu Miyata
- Department of Physics, Tokyo Metropolitan University, Tokyo 192-0397, Japan
| | - Chang-Hsiao Chen
- Department of Electrical Engineering, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Lain-Jong Li
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - Jiang Pu
- Department of Applied Physics, Nagoya University, Nagoya 464-8603, Japan
| | - Taishi Takenobu
- Department of Applied Physics, Nagoya University, Nagoya 464-8603, Japan
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18
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Zhou Z, Marcon P, Devaux X, Pigeat P, Bouché A, Migot S, Jaafar A, Arras R, Vergnat M, Ren L, Tornatzky H, Robert C, Marie X, George JM, Jaffrès HY, Stoffel M, Rinnert H, Wei Z, Renucci P, Calmels L, Lu Y. Large Perpendicular Magnetic Anisotropy in Ta/CoFeB/MgO on Full-Coverage Monolayer MoS 2 and First-Principles Study of Its Electronic Structure. ACS APPLIED MATERIALS & INTERFACES 2021; 13:32579-32589. [PMID: 34196522 DOI: 10.1021/acsami.1c08805] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
A perpendicularly magnetized spin injector with a high Curie temperature is a prerequisite for developing spin optoelectronic devices on two-dimensional (2D) materials working at room temperature (RT) with zero applied magnetic field. Here, we report the growth of Ta/CoFeB/MgO structures with large perpendicular magnetic anisotropy (PMA) on full-coverage monolayer (ML) molybdenum disulfide (MoS2). A large perpendicular interface anisotropy energy of 0.975 mJ/m2 has been obtained at the CoFeB/MgO interface, comparable to that observed in magnetic tunnel junction systems. It is found that the insertion of MgO between the ferromagnetic (FM) metal and the 2D material can effectively prevent the diffusion of the FM atoms into the 2D material. Moreover, the MoS2 ML favors a MgO(001) texture and plays a critical role in establishing the large PMA. First-principles calculations on a similar Fe/MgO/MoS2 structure reveal that the MgO thickness can modify the MoS2 band structure, from a direct band gap with 3ML-MgO to an indirect band gap with 7 ML-MgO. The proximity effect induced by Fe results in splitting of 10 meV in the valence band at the Γ point for the 3ML-MgO structure, while it is negligible for the 7 ML-MgO structure. These results pave the way to develop RT spin optoelectronic devices based on 2D transition-metal dichalcogenide materials.
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Affiliation(s)
- Ziqi Zhou
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences & Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100083, China
- Institut Jean Lamour, Université de Lorraine, CNRS UMR7198, Campus ARTEM, 2 Allée André Guinier, BP 50840, 54011 Nancy, France
| | - Paul Marcon
- CEMES, CNRS, Université de Toulouse, 29 rue Jeanne Marvig, BP 94347, F-31055 Toulouse, France
| | - Xavier Devaux
- Institut Jean Lamour, Université de Lorraine, CNRS UMR7198, Campus ARTEM, 2 Allée André Guinier, BP 50840, 54011 Nancy, France
| | - Philippe Pigeat
- Institut Jean Lamour, Université de Lorraine, CNRS UMR7198, Campus ARTEM, 2 Allée André Guinier, BP 50840, 54011 Nancy, France
| | - Alexandre Bouché
- Institut Jean Lamour, Université de Lorraine, CNRS UMR7198, Campus ARTEM, 2 Allée André Guinier, BP 50840, 54011 Nancy, France
| | - Sylvie Migot
- Institut Jean Lamour, Université de Lorraine, CNRS UMR7198, Campus ARTEM, 2 Allée André Guinier, BP 50840, 54011 Nancy, France
| | - Abdallah Jaafar
- Institut Jean Lamour, Université de Lorraine, CNRS UMR7198, Campus ARTEM, 2 Allée André Guinier, BP 50840, 54011 Nancy, France
| | - Rémi Arras
- CEMES, CNRS, Université de Toulouse, 29 rue Jeanne Marvig, BP 94347, F-31055 Toulouse, France
| | - Michel Vergnat
- Institut Jean Lamour, Université de Lorraine, CNRS UMR7198, Campus ARTEM, 2 Allée André Guinier, BP 50840, 54011 Nancy, France
| | - Lei Ren
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077 Toulouse, France
| | - Hans Tornatzky
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077 Toulouse, France
| | - Cedric Robert
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077 Toulouse, France
| | - Xavier Marie
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077 Toulouse, France
| | - Jean-Marie George
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
| | - Henri-Yves Jaffrès
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
| | - Mathieu Stoffel
- Institut Jean Lamour, Université de Lorraine, CNRS UMR7198, Campus ARTEM, 2 Allée André Guinier, BP 50840, 54011 Nancy, France
| | - Hervé Rinnert
- Institut Jean Lamour, Université de Lorraine, CNRS UMR7198, Campus ARTEM, 2 Allée André Guinier, BP 50840, 54011 Nancy, France
| | - Zhongming Wei
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences & Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100083, China
| | - Pierre Renucci
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077 Toulouse, France
| | - Lionel Calmels
- CEMES, CNRS, Université de Toulouse, 29 rue Jeanne Marvig, BP 94347, F-31055 Toulouse, France
| | - Yuan Lu
- Institut Jean Lamour, Université de Lorraine, CNRS UMR7198, Campus ARTEM, 2 Allée André Guinier, BP 50840, 54011 Nancy, France
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19
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Li W, Lu X, Wu J, Srivastava A. Optical control of the valley Zeeman effect through many-exciton interactions. NATURE NANOTECHNOLOGY 2021; 16:148-152. [PMID: 33257895 DOI: 10.1038/s41565-020-00804-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 10/26/2020] [Indexed: 06/12/2023]
Abstract
Charge carriers in two-dimensional transition metal dichalcogenides (TMDs), such as WSe2, have their spin and valley-pseudospin locked into an optically addressable index that is proposed as a basis for future information processing1,2. The manipulation of this spin-valley index, which carries a magnetic moment3, requires tuning its energy. This is typically achieved through an external magnetic field (B), which is practically cumbersome. However, the valley-contrasting optical Stark effect achieves valley control without B, but requires large incident powers4,5. Thus, other efficient routes to control the spin-valley index are desirable. Here we show that many-body interactions among interlayer excitons (IXs) in a WSe2/MoSe2 heterobilayer (HBL) induce a steady-state valley Zeeman splitting that corresponds to B ≈ 6 T. This anomalous splitting, present at incident powers as low as microwatts, increases with power and is able to enhance, suppress or even flip the sign of a B-induced splitting. Moreover, the g-factor of valley Zeeman splitting can be tuned by ~30% with incident power. In addition to valleytronics, our results could prove helpful to achieve optical non-reciprocity using two-dimensional materials.
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Affiliation(s)
- Weijie Li
- Department of Physics, Emory University, Atlanta, GA, USA
| | - Xin Lu
- Department of Physics, Emory University, Atlanta, GA, USA
| | - Jiatian Wu
- Department of Physics, Emory University, Atlanta, GA, USA
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20
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Zhao S, Li X, Dong B, Wang H, Wang H, Zhang Y, Han Z, Zhang H. Valley manipulation in monolayer transition metal dichalcogenides and their hybrid systems: status and challenges. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2021; 84:026401. [PMID: 33440363 DOI: 10.1088/1361-6633/abdb98] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Recently, the emerging conceptual valley-related devices have attracted much attention due to the progress on generating, controlling, and detecting the valley degree of freedom in the transition metal dichalcogenide (TMD) monolayers. In general, it is known that achieving valley degree of freedom with long valley lifetime is crucial in the implementation of valleytronic devices. Here, we provide a brief introduction of the basic understandings of valley degree of freedom. We as well review the recent experimental advancement in the modulation of valley degree of freedom. The strategies include optical/magnetic/electric field tuning, moiré patterns, plasmonic metasurface, defects and strain engineering. In addition, we summarize the corresponding mechanisms, which can help to obtain large degree of polarization and long valley lifetimes in monolayer TMDs. Based on these methods, two-dimensional valley-optoelectronic systems based on TMD heterostructures can be constructed, providing opportunities for such as the new paradigm in data processing and transmission. Challenges and perspectives on the development of valleytronics are highlighted as well.
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Affiliation(s)
- Siwen Zhao
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education, Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen 518060, People's Republic of China
- College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, People's Republic of China
| | - Xiaoxi Li
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, People's Republic of China
- School of Material Science and Engineering, University of Science and Technology of China, Hefei 230026, People's Republic of China
| | - Baojuan Dong
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006, People's Republic of China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, People's Republic of China
| | - Huide Wang
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education, Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen 518060, People's Republic of China
| | - Hanwen Wang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, People's Republic of China
- School of Material Science and Engineering, University of Science and Technology of China, Hefei 230026, People's Republic of China
| | - Yupeng Zhang
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education, Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen 518060, People's Republic of China
| | - Zheng Han
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006, People's Republic of China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, People's Republic of China
| | - Han Zhang
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education, Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen 518060, People's Republic of China
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21
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Liu DS, Wu J, Xu H, Wang Z. Emerging Light-Emitting Materials for Photonic Integration. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2003733. [PMID: 33306201 DOI: 10.1002/adma.202003733] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 07/26/2020] [Indexed: 06/12/2023]
Abstract
The arrival of the information explosion era is urging the development of large-bandwidth high-data-rate optical interconnection technology. Up to now, the biggest stumbling block in optical interconnections has been the lack of efficient light sources despite significant progress that has been made in germanium-on-silicon (Ge-on-Si) and III-V-on-silicon (III-V-on-Si) lasers. 2D materials and metal halide perovskites have attracted much attention in recent years, and exhibit distinctive advantages in the application of on-chip light emitters. Herein, this Progress Report reviews the recent progress made in light-emitting materials with a focus on new materials, i.e., 2D materials and metal halide perovskites. The report briefly introduces the current status of Ge-on-Si and III-V-on-Si lasers and discusses the advances of 2D and perovskite light-emitting materials for photonic integration, including their optical properties, preparation methods, as well as the light sources based on these materials. Finally, challenges and perspectives of these emerging materials on the way to the efficient light sources are discussed.
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Affiliation(s)
- De-Sheng Liu
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Jiang Wu
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Hongxing Xu
- School of Physics and Technology, Wuhan University, Wuhan, 430072, China
| | - Zhiming Wang
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, 610054, China
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Shen H, Ren J, Li J, Chen Y, Lan S, Wang J, Wang H, Li D. Multistate Memory Enabled by Interface Engineering Based on Multilayer Tungsten Diselenide. ACS APPLIED MATERIALS & INTERFACES 2020; 12:58428-58434. [PMID: 33332079 DOI: 10.1021/acsami.0c19443] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The diversification of data types and the explosive increase of data size in the information era continuously required to miniaturize the memory devices with high data storage capability. Atomically thin two-dimensional (2D) transition metal dichalcogenides (TMDs) are promising candidates for flexible and transparent electronic and optoelectronic devices with high integration density. Multistate memory devices based on TMDs could possess high data storage capability with a large integration density and thus exhibit great potential applications in the field of data storage. Here, we report the multistate data storage based on multilayer tungsten diselenide (WSe2) transistors by interface engineering. The multiple resistance states of the WSe2 transistors are achieved by applying different gate voltage pulses, and the switching ratio of the memory can be as large as 105 with high cycling endurance. The water and oxygen molecules (H2O/O2) trapped at the interface between the SiO2 substrate and WSe2 introduce the trap states and thus the large hysteresis of the transfer curves, which leads to the multistate data storage. In addition, the laminated Au thin film electrodes make the contact interface between the electrodes and WSe2 free of dangling bond and Fermi level pinning, thus giving rise to the excellent performance of memory devices. Importantly, the interface trap states can be easily controlled by a simple oxygen plasma treatment of the SiO2 substrate, and subsequently, the performance of the multistate memory devices can be manipulated. Our findings provide a simple and efficient strategy to engineer the interface states for the multistate data storage applications and would motivate more investigations on the trap state-associated applications.
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Affiliation(s)
- Hongzhi Shen
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Junwen Ren
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Junze Li
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yingying Chen
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Shangui Lan
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Jiaqi Wang
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Haizhen Wang
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Dehui Li
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China
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Chen Y, Ma J, Liu Z, Li J, Duan X, Li D. Manipulation of Valley Pseudospin by Selective Spin Injection in Chiral Two-Dimensional Perovskite/Monolayer Transition Metal Dichalcogenide Heterostructures. ACS NANO 2020; 14:15154-15160. [PMID: 33108721 DOI: 10.1021/acsnano.0c05343] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Monolayer two-dimensional (2D) transition metal dichalcogenides (TMDs) have attracted great interest in spintronics and valleytronics due to the spin-valley locking effect. To efficiently control and manipulate the valley pseudospin is of paramount importance for valley-based electronics and optoelectronics. A variety of strategies have been developed to address the valley pseudospin including optical, electrical, and magnetic methods; nonetheless, they involve either below liquid-nitrogen temperature or an external magnetic field, which increases the cost and complexity of the devices. Here, we report a straightforward way to manipulate valley polarization in monolayer TMDs via selective spin injection in chiral 2D perovskite/monolayer TMD (e.g., MoS2 and WSe2) van der Waals heterostructures without requiring an external magnetic field or specially designed device structures. We show the dangling-bond-free vdW interface can allow an impressive average spin injection efficiency of 78% to produce persistent valley polarization in monolayer MoS2 (WSe2) over 10% from liquid-nitrogen temperature to above 200 K. We attribute the valley polarization of monolayer MoS2 (WSe2) to selective spin injection from chiral 2D perovskites, which can effectively introduce population imbalance between valleys in monolayer MoS2 (WSe2). Our findings provide an alternative strategy to manipulate the valley polarization in TMDs without requiring circularly polarized light excitation, below liquid-nitrogen temperature, or external magnetic field, and thus would promote the development of perovskite-based spintronic and valleytronic devices.
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Affiliation(s)
- Yingying Chen
- School of Optical and Electronic Information and Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Jiaqi Ma
- School of Optical and Electronic Information and Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Zeyi Liu
- School of Optical and Electronic Information and Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Junze Li
- School of Optical and Electronic Information and Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Xiangfeng Duan
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Dehui Li
- School of Optical and Electronic Information and Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China
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Li L, Shao L, Liu X, Gao A, Wang H, Zheng B, Hou G, Shehzad K, Yu L, Miao F, Shi Y, Xu Y, Wang X. Room-temperature valleytronic transistor. NATURE NANOTECHNOLOGY 2020; 15:743-749. [PMID: 32690885 DOI: 10.1038/s41565-020-0727-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 06/03/2020] [Indexed: 06/11/2023]
Abstract
Valleytronics, based on the valley degree of freedom rather than charge, is a promising candidate for next-generation information devices beyond complementary metal-oxide-semiconductor (CMOS) technology1-4. Although many intriguing valleytronic properties have been explored based on excitonic injection or the non-local response of transverse current schemes at low temperature4-7, demonstrations of valleytronic building blocks similar to transistors in electronics, especially at room temperature, remain elusive. Here, we report a solid-state device that enables a full sequence of generating, propagating, detecting and manipulating valley information at room temperature. Chiral nanocrescent plasmonic antennae8 are used to selectively generate valley-polarized carriers in MoS2 through hot-electron injection under linearly polarized infrared excitation. These long-lived valley-polarized free carriers can be detected in a valley Hall configuration9-11 even without charge current, and can propagate over 18 μm by means of drift. In addition, electrostatic gating allows us to modulate the magnitude of the valley Hall voltage. The electrical valley Hall output could drive the valley manipulation of a cascaded stage, rendering the device able to serve as a transistor free of charge current with pure valleytronic input/output. Our results demonstrate the possibility of encoding and processing information by valley degree of freedom, and provide a universal strategy to study the Berry curvature dipole in quantum materials.
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Affiliation(s)
- Lingfei Li
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China
- Colleges of ISEE and Microelectronics, ZJU-Hangzhou Global Scientific and Technological Innovation Center, ZJU-UIUC Institute, State Key Labs of Silicon Materials and Modern Optical Instruments, Zhejiang University, Hangzhou, China
| | - Lei Shao
- Beijing Computational Science Research Centre, Beijing, China
| | - Xiaowei Liu
- School of Physics, Nanjing University, Nanjing, China
| | - Anyuan Gao
- School of Physics, Nanjing University, Nanjing, China
| | - Hao Wang
- Beijing Computational Science Research Centre, Beijing, China
| | - Binjie Zheng
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China
| | - Guozhi Hou
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China
| | - Khurram Shehzad
- Colleges of ISEE and Microelectronics, ZJU-Hangzhou Global Scientific and Technological Innovation Center, ZJU-UIUC Institute, State Key Labs of Silicon Materials and Modern Optical Instruments, Zhejiang University, Hangzhou, China
| | - Linwei Yu
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China
| | - Feng Miao
- School of Physics, Nanjing University, Nanjing, China
| | - Yi Shi
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China
| | - Yang Xu
- Colleges of ISEE and Microelectronics, ZJU-Hangzhou Global Scientific and Technological Innovation Center, ZJU-UIUC Institute, State Key Labs of Silicon Materials and Modern Optical Instruments, Zhejiang University, Hangzhou, China.
| | - Xiaomu Wang
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China.
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Zhang J, Cong L, Zhang K, Jin X, Li X, Wei Y, Li Q, Jiang K, Luo Y, Fan S. Mixed-Dimensional Vertical Point p -n Junctions. ACS NANO 2020; 14:3181-3189. [PMID: 32083843 DOI: 10.1021/acsnano.9b08367] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Mixed-dimensional van der Waals (vdW) heterostructures composed of one-dimensional (1D) and two-dimensional (2D) materials have exhibited great potential in nanoelectronics and nano-optoelectronics. In this study, we present a vertical point p-n junction (VPpnJ), in which a vertical stacked molybdenum disulfide/tungsten diselenide p-n junction is sandwiched between two cross-stacked metallic carbon nanotubes (CNTs). The device can be transformed from p-n junction to n-n junction via gate modulation. As a photodetector, the VPpnJ device can work in three different modes by setting the appropriate gating voltages. The photosensitive areas are localized around the top CNT, bottom CNT, and the cross point at VG = -10 V, 10 V, and ∼0 V, respectively. In the p-n regime at the negative gate voltage, the VPpnJ device showed an obvious photovoltaic effect. The external quantum efficiency of the VPpnJ can reach 42.7%. The electrical control of the electronic and optoelectronic characteristics can be mainly attributed to the gate-tunable interfacial built-in electric fields in the heterostructures. The progress also reveals the functional diversity of such 1D/2D mixed-dimensional heterostructures, which will be prospects for future nanoelectronics and nano-optoelectronics.
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Affiliation(s)
- Jin Zhang
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics and Tsinghua-Foxconn Nanotechnology Research Center, Tsinghua University, Beijing 100084, China
- Beijing National Research Center for Information Science and Technology (BNRist), Department of Electronic Engineering, Tsinghua University, Beijing 100084, China
| | - Lin Cong
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics and Tsinghua-Foxconn Nanotechnology Research Center, Tsinghua University, Beijing 100084, China
| | - Ke Zhang
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics and Tsinghua-Foxconn Nanotechnology Research Center, Tsinghua University, Beijing 100084, China
| | - Xiang Jin
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics and Tsinghua-Foxconn Nanotechnology Research Center, Tsinghua University, Beijing 100084, China
| | - Xuanzhang Li
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics and Tsinghua-Foxconn Nanotechnology Research Center, Tsinghua University, Beijing 100084, China
| | - Yang Wei
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics and Tsinghua-Foxconn Nanotechnology Research Center, Tsinghua University, Beijing 100084, China
| | - Qunqing Li
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics and Tsinghua-Foxconn Nanotechnology Research Center, Tsinghua University, Beijing 100084, China
| | - Kaili Jiang
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics and Tsinghua-Foxconn Nanotechnology Research Center, Tsinghua University, Beijing 100084, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
| | - Yi Luo
- Beijing National Research Center for Information Science and Technology (BNRist), Department of Electronic Engineering, Tsinghua University, Beijing 100084, China
| | - Shoushan Fan
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics and Tsinghua-Foxconn Nanotechnology Research Center, Tsinghua University, Beijing 100084, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
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Li Z, Xu B, Liang D, Pan A. Polarization-Dependent Optical Properties and Optoelectronic Devices of 2D Materials. RESEARCH (WASHINGTON, D.C.) 2020; 2020:5464258. [PMID: 33029588 PMCID: PMC7521027 DOI: 10.34133/2020/5464258] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 07/26/2020] [Indexed: 01/12/2023]
Abstract
The development of optoelectronic devices requires breakthroughs in new material systems and novel device mechanisms, and the demand recently changes from the detection of signal intensity and responsivity to the exploration of sensitivity of polarized state information. Two-dimensional (2D) materials are a rich family exhibiting diverse physical and electronic properties for polarization device applications, including anisotropic materials, valleytronic materials, and other hybrid heterostructures. In this review, we first review the polarized-light-dependent physical mechanism in 2D materials, then present detailed descriptions in optical and optoelectronic properties, involving Raman shift, optical absorption, and light emission and functional optoelectronic devices. Finally, a comment is made on future developments and challenges. The plethora of 2D materials and their heterostructures offers the promise of polarization-dependent scientific discovery and optoelectronic device application.
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Affiliation(s)
- Ziwei Li
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, College of Materials and Engineering, Hunan University, Changsha, Hunan 410082, China
| | - Boyi Xu
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, College of Materials and Engineering, Hunan University, Changsha, Hunan 410082, China
| | - Delang Liang
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, College of Materials and Engineering, Hunan University, Changsha, Hunan 410082, China
| | - Anlian Pan
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, College of Materials and Engineering, Hunan University, Changsha, Hunan 410082, China
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27
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Shi WB, He J, Li QX, She XC, Wang D, Jing H, Zhang RL, Zhao JZ, Peng RW, Xu H, Wang M. Asymmetric valley polarization and photoluminescence in MoS 2/MoO 3 heterostructure. OPTICS EXPRESS 2019; 27:38451-38462. [PMID: 31878612 DOI: 10.1364/oe.27.038451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 11/27/2019] [Indexed: 06/10/2023]
Abstract
We investigate circularly polarized photoluminescence (PL) in the MoS2/MoO3 heterostructure, which was fabricated by transferring MoS2 monolayer to cover the MoO3 few layers on the SiO2/Si substrate. It is shown that the PL with the same helicity as the excitation light is dominant due to the inherent chiral optical selectivity, which allows exciting one of the valleys in MoS2 monolayer. The degree of polarization (DP), which characterizes the intensity difference of two chiral components of PL, is unequal for the right-handed and left-handed circularly polarized excitations in the MoS2/MoO3 heterostructure. This effect is different from the one in pristine MoS2. Our Raman spectra results together with ab initio calculations indicate the p-doped features of the MoS2 when it covers the MoO3 layers. Thus the possible explanation of the unequal DP is that the p-doping process generates a built-in voltage and therefore brings the difference of electron-hole overlaps between K and K' valleys. Namely the asymmetric valley polarization may be obtained in the MoS2/MoO3 heterostructure. Consequently, the circularly polarized PL caused by the electron-hole recombination at K and K' valleys manifests unequal DP for the right-handed and left-handed helix excitations. This asymmetric effect is further enhanced by decreasing the temperature in the MoS2/MoO3 heterostructure. Our investigation provides a unique platform for developing novel two-dimensional valleytronic devices.
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Karni O, Barré E, Lau SC, Gillen R, Ma EY, Kim B, Watanabe K, Taniguchi T, Maultzsch J, Barmak K, Page RH, Heinz TF. Infrared Interlayer Exciton Emission in MoS_{2}/WSe_{2} Heterostructures. PHYSICAL REVIEW LETTERS 2019; 123:247402. [PMID: 31922842 DOI: 10.1103/physrevlett.123.247402] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Indexed: 05/12/2023]
Abstract
We report light emission around 1 eV (1240 nm) from heterostructures of MoS_{2} and WSe_{2} transition metal dichalcogenide monolayers. We identify its origin in an interlayer exciton (ILX) by its wide spectral tunability under an out-of-plane electric field. From the static dipole moment of the state, its temperature and twist-angle dependence, and comparison with electronic structure calculations, we assign this ILX to the fundamental interlayer transition between the K valleys in this system. Our findings gain access to the interlayer physics of the intrinsically incommensurate MoS_{2}/WSe_{2} heterostructure, including moiré and valley pseudospin effects, and its integration with silicon photonics and optical fiber communication systems operating at wavelengths longer than 1150 nm.
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Affiliation(s)
- Ouri Karni
- Department of Applied Physics, Stanford University, Stanford, California, 94305, USA
| | - Elyse Barré
- Department of Electrical Engineering, Stanford University, Stanford, California, 94305, USA
| | - Sze Cheung Lau
- Department of Applied Physics, Stanford University, Stanford, California, 94305, USA
| | - Roland Gillen
- Department Physik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudstrasse 7, 91058 Erlangen, Germany
| | - Eric Yue Ma
- Department of Applied Physics, Stanford University, Stanford, California, 94305, USA
- SLAC National Accelerator Laboratory, Menlo Park, California, 94025, USA
| | - Bumho Kim
- Department of Mechanical Engineering, Columbia University, New York, New York 10027, USA
| | - Kenji Watanabe
- National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Takashi Taniguchi
- National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Janina Maultzsch
- Department Physik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudstrasse 7, 91058 Erlangen, Germany
| | - Katayun Barmak
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, USA
| | - Ralph H Page
- Department of Applied Physics, Stanford University, Stanford, California, 94305, USA
- SLAC National Accelerator Laboratory, Menlo Park, California, 94025, USA
| | - Tony F Heinz
- Department of Applied Physics, Stanford University, Stanford, California, 94305, USA
- SLAC National Accelerator Laboratory, Menlo Park, California, 94025, USA
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29
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Wang J, Lin F, Verzhbitskiy I, Watanabe K, Taniguchi T, Martin J, Eda G. Polarity Tunable Trionic Electroluminescence in Monolayer WSe 2. NANO LETTERS 2019; 19:7470-7475. [PMID: 31517494 DOI: 10.1021/acs.nanolett.9b03215] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Monolayer WSe2 exhibits luminescence arising from various types of exciton complexes due to strong many-body effects. Here, we demonstrate selective electrical excitation of positive and negative trions in van der Waals metal-insulator-semiconductor (MIS) heterostructure consisting of few-layer graphene (FLG), hexagonal boron nitride (hBN), and monolayer WSe2. Intentional unbalanced injection of electrons and holes is achieved via field-emission tunneling and electrostatic accumulation. The device exhibits planar electroluminescence from either positive trion X+ or negative trion X- depending on the bias conditions. We show that hBN serves as a tunneling barrier material allowing selective injection of electron or holes into WSe2 from FLG layer. Our observation offers prospects for hot carrier injection, trion manipulation, and on-chip excitonic devices based on two-dimensional semiconductors.
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Affiliation(s)
- Junyong Wang
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542
- Centre for Advanced 2D Materials , National University of Singapore , 6 Science Drive 2 , Singapore 117546
| | - Fanrong Lin
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542
- Centre for Advanced 2D Materials , National University of Singapore , 6 Science Drive 2 , Singapore 117546
| | - Ivan Verzhbitskiy
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542
- Centre for Advanced 2D Materials , National University of Singapore , 6 Science Drive 2 , Singapore 117546
| | - Kenji Watanabe
- National Institute for Material Science , 1-1 Namiki , Tsukuba 305-0044 , Japan
| | - Takashi Taniguchi
- National Institute for Material Science , 1-1 Namiki , Tsukuba 305-0044 , Japan
| | - Jens Martin
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542
- Centre for Advanced 2D Materials , National University of Singapore , 6 Science Drive 2 , Singapore 117546
| | - Goki Eda
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117542
- Centre for Advanced 2D Materials , National University of Singapore , 6 Science Drive 2 , Singapore 117546
- Department of Chemistry , National University of Singapore , 3 Science Drive 3 , Singapore 117543
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30
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Norden T, Zhao C, Zhang P, Sabirianov R, Petrou A, Zeng H. Giant valley splitting in monolayer WS 2 by magnetic proximity effect. Nat Commun 2019; 10:4163. [PMID: 31519871 PMCID: PMC6744439 DOI: 10.1038/s41467-019-11966-4] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 07/30/2019] [Indexed: 11/17/2022] Open
Abstract
Lifting the valley degeneracy of monolayer transition metal dichalcogenides (TMDs) would allow versatile control of the valley degree of freedom. We report a giant valley exciton splitting of 16 meV/T for monolayer WS2, using the proximity effect from an EuS substrate, which is enhanced by nearly two orders of magnitude from that obtained by an external magnetic field. More interestingly, a sign reversal of the valley splitting is observed as compared to that of WSe2 on EuS. Using first principles calculations, we investigate the complex behavior of exchange interactions between TMDs and EuS. The sign reversal is attributed to competing ferromagnetic (FM) and antiferromagnetic (AFM) exchange interactions for Eu- and S- terminated EuS surface sites. They act differently on the conduction and valence bands of WS2 compared to WSe2. Tuning the sign and magnitude of the valley exciton splitting offers opportunities for control of valley pseudospin for quantum information processing. Valley degree of freedom promises the additional control of electrons in 2D materials but is limited by small valley splitting. Here the authors show heavily enhanced valley splitting in monolayer WS2 on EuS substrate due to competing ferromagnetic and antiferromagnetic exchange interactions for Eu- and S-terminated EuS surface sites.
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Affiliation(s)
- Tenzin Norden
- Department of Physics, University at Buffalo, the State University of New York, Buffalo, NY, 14260, USA
| | - Chuan Zhao
- Department of Physics, University at Buffalo, the State University of New York, Buffalo, NY, 14260, USA
| | - Peiyao Zhang
- Department of Physics, University at Buffalo, the State University of New York, Buffalo, NY, 14260, USA
| | - Renat Sabirianov
- Department of Physics, University of Nebraska-Omaha, Omaha, NE, 68182, USA.
| | - Athos Petrou
- Department of Physics, University at Buffalo, the State University of New York, Buffalo, NY, 14260, USA.
| | - Hao Zeng
- Department of Physics, University at Buffalo, the State University of New York, Buffalo, NY, 14260, USA.
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31
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Xu X, Ma Y, Zhang T, Lei C, Huang B, Dai Y. Nonmetal-Atom-Doping-Induced Valley Polarization in Single-Layer Tl 2O. J Phys Chem Lett 2019; 10:4535-4541. [PMID: 31342751 DOI: 10.1021/acs.jpclett.9b01602] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Valleytronics that relies on the valley degree of freedom is attracting growing interest because it provides a new platform for information storage. One obstacle in this field is to realize valley polarization in an efficient route to manipulate the valley physics. Here we propose a strategy to induce valley polarization by nonmetal atom doping in single-layer Tl2O. Owing to the intrinsic inversion asymmetry and large spin-orbit coupling, there are a two-fold valley degeneracy and an excellent spin-valley independence in single-layer Tl2O. Upon introducing C/N atoms in single-layer Tl2O, the intriguing valley polarization successfully appears, and the obtained polarization strengths are considerable. In particular, for N-doped case, the top valence band locates around the Fermi level, and there are no impurity states in the band gap, which is desirable for practical applications. It is predicted that these valley polarizations can be effectively engineered under the magnetic field and external strain, suggesting that the control of valley physics in single-layer Tl2O is accessible.
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Affiliation(s)
- Xilong Xu
- School of Physics, State Key Laboratory of Crystal Materials , Shandong University , Shandanan Street 27 , Jinan 250100 , China
| | - Yandong Ma
- School of Physics, State Key Laboratory of Crystal Materials , Shandong University , Shandanan Street 27 , Jinan 250100 , China
| | - Ting Zhang
- School of Physics, State Key Laboratory of Crystal Materials , Shandong University , Shandanan Street 27 , Jinan 250100 , China
| | - Chengan Lei
- School of Physics, State Key Laboratory of Crystal Materials , Shandong University , Shandanan Street 27 , Jinan 250100 , China
| | - Baibiao Huang
- School of Physics, State Key Laboratory of Crystal Materials , Shandong University , Shandanan Street 27 , Jinan 250100 , China
| | - Ying Dai
- School of Physics, State Key Laboratory of Crystal Materials , Shandong University , Shandanan Street 27 , Jinan 250100 , China
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Kaviraj B, Sahoo D. Retracted Article: Physics of excitons and their transport in two dimensional transition metal dichalcogenide semiconductors. RSC Adv 2019; 9:25439-25461. [PMID: 35530097 PMCID: PMC9070122 DOI: 10.1039/c9ra03769a] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Accepted: 07/17/2019] [Indexed: 11/21/2022] Open
Abstract
Two-dimensional (2D) group-VI transition metal dichalcogenide (TMD) semiconductors, such as MoS2, MoSe2, WS2 and others manifest strong light matter coupling and exhibit direct band gaps which lie in the visible and infrared spectral regimes. These properties make them potentially interesting candidates for applications in optics and optoelectronics. The excitons found in these materials are tightly bound and dominate the optical response, even at room temperatures. Large binding energies and unique exciton fine structure make these materials an ideal platform to study exciton behaviors in two-dimensional systems. This review article mainly focuses on studies of mechanisms that control dynamics of excitons in 2D systems - an area where there remains a lack of consensus in spite of extensive research. Firstly, we focus on the kinetics of dark and bright excitons based on a rate equation model and discuss on the role of previous 'unsuspected' dark excitons in controlling valley polarization. Intrinsically, dark and bright exciton energy splitting plays a key role in modulating the dynamics. In the second part, we review the excitation energy-dependent possible characteristic relaxation pathways of photoexcited carriers in monolayer and bilayer systems. In the third part, we review the extrinsic factors, in particular the defects that are so prevalent in single layer TMDs, affecting exciton dynamics, transport and non-radiative recombination such as exciton-exciton annihilation. Lastly, the optical response due to pump-induced changes in TMD monolayers have been reviewed using femtosecond pump-probe spectroscopy which facilitates the analysis of underlying physical process just after the excitation.
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Affiliation(s)
- Bhaskar Kaviraj
- Department of Physics, School of Natural Sciences, Shiv Nadar University NH91, Gautam Budh Nagar Greater Noida Uttar Pradesh 201314 India
| | - Dhirendra Sahoo
- Department of Physics, School of Natural Sciences, Shiv Nadar University NH91, Gautam Budh Nagar Greater Noida Uttar Pradesh 201314 India
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He X, Zhao L, Zhou Z, Zhang S, Pan H, Chen J, Xu J. Near unity charge separation efficiency leads to pure ultraviolet emission in few layer graphene nanosheets. NANOTECHNOLOGY 2019; 30:295201. [PMID: 30812023 DOI: 10.1088/1361-6528/ab0afe] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Two-dimensional materials with van der Waals structure attract intense interest due to their high performance in ultrathin optoelectronic devices. In particular, the high efficiency charge separation between the two-dimensional materials can significantly improve the photo-response of a given device. Here we report the discovery of pure ultraviolet (UV) emission from few layer graphene nanosheets (GNS). Near unity charge separation efficiency is key to pure UV emission. The dynamics of an excited electron were analyzed using femtosecond transient absorption techniques. Electron transfer is observed from surface defect states induced by oxygen-containing functional groups to intrinsic sp2 domain states in few layer GNS. Moreover, a solar blind response device based on few layer GNS with a high on-off ratio was successfully fabricated.
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Affiliation(s)
- Xiaoxiao He
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, People's Republic of China
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Wu D, Li W, Rai A, Wu X, Movva HCP, Yogeesh MN, Chu Z, Banerjee SK, Akinwande D, Lai K. Visualization of Local Conductance in MoS 2/WSe 2 Heterostructure Transistors. NANO LETTERS 2019; 19:1976-1981. [PMID: 30779591 DOI: 10.1021/acs.nanolett.8b05159] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The vertical stacking of van der Waals (vdW) materials introduces a new degree of freedom to the research of two-dimensional (2D) systems. The interlayer coupling strongly influences the band structure of the heterostructures, resulting in novel properties that can be utilized for electronic and optoelectronic applications. Based on microwave microscopy studies, we report quantitative electrical imaging on gated molybdenum disulfide (MoS2)/tungsten diselenide (WSe2) heterostructure devices, which exhibit an intriguing antiambipolar effect in their transfer characteristics. Interestingly, in the region with significant source-drain current, electrons in the n-type MoS2 and holes in the p-type WSe2 segments are nearly balanced, whereas the heterostructure area is depleted of mobile charges. The spatial evolution of local conductance can be ascribed to the lateral band bending and formation of depletion regions along the line of MoS2-heterostructure-WSe2. Our work vividly demonstrates the microscopic origin of novel transport behaviors, which is important for the vibrant field of vdW heterojunction research.
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Affiliation(s)
- Di Wu
- Department of Physics , The University of Texas at Austin , Austin , Texas 78712 , United States
| | - Wei Li
- Microelectronics Research Center, Department of Electrical and Computer Engineering , The University of Texas at Austin , Austin , Texas 78758 , United States
| | - Amritesh Rai
- Microelectronics Research Center, Department of Electrical and Computer Engineering , The University of Texas at Austin , Austin , Texas 78758 , United States
| | - Xiaoyu Wu
- Department of Physics , The University of Texas at Austin , Austin , Texas 78712 , United States
| | - Hema C P Movva
- Microelectronics Research Center, Department of Electrical and Computer Engineering , The University of Texas at Austin , Austin , Texas 78758 , United States
| | - Maruthi N Yogeesh
- Microelectronics Research Center, Department of Electrical and Computer Engineering , The University of Texas at Austin , Austin , Texas 78758 , United States
| | - Zhaodong Chu
- Department of Physics , The University of Texas at Austin , Austin , Texas 78712 , United States
| | - Sanjay K Banerjee
- Microelectronics Research Center, Department of Electrical and Computer Engineering , The University of Texas at Austin , Austin , Texas 78758 , United States
| | - Deji Akinwande
- Microelectronics Research Center, Department of Electrical and Computer Engineering , The University of Texas at Austin , Austin , Texas 78758 , United States
| | - Keji Lai
- Department of Physics , The University of Texas at Austin , Austin , Texas 78712 , United States
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Liu Y, Zhang S, He J, Wang ZM, Liu Z. Recent Progress in the Fabrication, Properties, and Devices of Heterostructures Based on 2D Materials. NANO-MICRO LETTERS 2019; 11:13. [PMID: 34137973 PMCID: PMC7770868 DOI: 10.1007/s40820-019-0245-5] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 01/28/2019] [Indexed: 05/03/2023]
Abstract
With a large number of researches being conducted on two-dimensional (2D) materials, their unique properties in optics, electrics, mechanics, and magnetics have attracted increasing attention. Accordingly, the idea of combining distinct functional 2D materials into heterostructures naturally emerged that provides unprecedented platforms for exploring new physics that are not accessible in a single 2D material or 3D heterostructures. Along with the rapid development of controllable, scalable, and programmed synthesis techniques of high-quality 2D heterostructures, various heterostructure devices with extraordinary performance have been designed and fabricated, including tunneling transistors, photodetectors, and spintronic devices. In this review, we present a summary of the latest progresses in fabrications, properties, and applications of different types of 2D heterostructures, followed by the discussions on present challenges and perspectives of further investigations.
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Affiliation(s)
- Yanping Liu
- School of Physics and Electronics, Hunan Key Laboratory for Super-Microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, 410083, Hunan, People's Republic of China.
| | - Siyu Zhang
- School of Physics and Electronics, Hunan Key Laboratory for Super-Microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, 410083, Hunan, People's Republic of China
| | - Jun He
- School of Physics and Electronics, Hunan Key Laboratory for Super-Microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, 410083, Hunan, People's Republic of China
| | - Zhiming M Wang
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, People's Republic of China.
| | - Zongwen Liu
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, NSW, 2006, Australia.
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36
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Bai C, Yang Y, Bai L. Giant magnetoresistance control and nontrivial metallic state manipulation in a transition-metal dichalcogenide spin-valve using a gate voltage. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:495801. [PMID: 30431019 DOI: 10.1088/1361-648x/aaec55] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Here, we have theoretically studied the valley- and spin-resolved transport in a monolayer transition metal dichalcogenides based spin valve device, where both the Rashba spin orbit interaction and a gate voltage coexist in the central lead. In contrast to conventional semiconductor, nontrivial metallic states, such as, normal Rashba metal state (NRMS), anomalous Rashba metal state (ARMS), and Rashba ring metal state (RRMS), can be generated and manipulated by Rashba spin orbit interaction without the magnetic effect. For a nonferromagnetic double junction, it was found that the valley- and spin-resolved tunneling conductance can be effectively tuned by the incident energy, the junction length, the Rashba spin orbit interaction strength, and the gate voltage. Due to the spin texture and the Fermi wavevectors in the central lead, both the tunneling coefficient and the tunneling conductance all exhibit the remarkable characteristic features which enable us to diagnose the special states. For a ferromagnetic spin valve device, the resulting nontrivial metallic groundstates in the central lead also demonstrate directly in the giant magnetoresistance with notable unique features. We have further revealed that a perfect valley and spin giant magnetoresistance stems from the spin splitting and the spin-valley coupling. These valley- and spin-resolved phenomena are interesting for both fundamental research and applications.
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Affiliation(s)
- Chunxu Bai
- College of Physics and Electronic Engineering, Xinyang Normal University, Xinyang 464000, People's Republic of China
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37
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Wang J, Verzhbitskiy I, Eda G. Electroluminescent Devices Based on 2D Semiconducting Transition Metal Dichalcogenides. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1802687. [PMID: 30118543 DOI: 10.1002/adma.201802687] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 06/09/2018] [Indexed: 05/08/2023]
Abstract
Ultrathin layers of van der Waals inorganic semiconductors represent a new class of excitonic materials with attractive light-emitting properties. Recent observation of valley polarization, optically pumped lasing, exciton-polaritons, and single-photon emission highlights the exciting prospects for two-dimensional (2D) semiconductors for applications in novel photonic devices. Development of efficient and reliable light sources based on excitonic electroluminescence in 2D semiconductors is of fundamental importance toward the practical implementation of photonic devices. Achieving electroluminescence in these atomically thin layers requires unconventional device designs and in-depth understanding of the carrier injection and transport mechanisms. Herein, various strategies for electrically generating excitons in 2D semiconducting transition metal dichalcogenides such as monolayer MoS2 are reviewed and challenges and opportunities are outlined. Furthermore, novel device concepts such as tunable chiral emission, electrically driven quantum emission, and high-frequency modulation are highlighted.
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Affiliation(s)
- Junyong Wang
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117542, Singapore
- Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore, 117546, Singapore
| | - Ivan Verzhbitskiy
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117542, Singapore
- Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore, 117546, Singapore
| | - Goki Eda
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117542, Singapore
- Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore, 117546, Singapore
- Department of Chemistry, National University of Singapore, 2 Science Drive 3, Singapore, 117543, Singapore
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38
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Kuklin AV, Shostak SA, Kuzubov AA. Two-Dimensional Lattices of VN: Emergence of Ferromagnetism and Half-Metallicity on Nanoscale. J Phys Chem Lett 2018; 9:1422-1428. [PMID: 29502418 DOI: 10.1021/acs.jpclett.7b03276] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Two-dimensional (2D) ferromagnets with high spin-polarization ratio and high Curie temperature are crucial for developing next-generation spintronic nanodevices. Using first-principles calculations, we predict two polymorphic modifications ( t-VN and h-VN) of 2D VN lattices that have robust intrinsic ferromagnetic properties and high Curie temperatures. Whereas t-VN has 99.9% of spin polarization at the Fermi level, h-VN possesses a half-metallic type of conductivity and keeps it after contact with semiconducting MoS2, which can be used as the substrate for h-VN synthesis and valley polarized contacts. Magnetocrystalline anisotropy energy of 2D VN polymorphs is found to be at least an order larger than those of Fe and Ni bulks. The phonon spectra and ab initio molecular dynamic simulation prove that 2D VN lattices have a high thermodynamic stability. These advantages demonstrate that the VN monolayers should be promising candidates for low-dimensional spintronic devices.
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Affiliation(s)
- Artem V Kuklin
- Siberian Federal University , 79 Svobodny pr ., Krasnoyarsk 660041 , Russia
- Department of Chemistry , Kyungpook National University , 80 Daehakro, Bukgu , Daegu 41566 , Republic of Korea
| | - Svetlana A Shostak
- Department of Chemistry , Kyungpook National University , 80 Daehakro, Bukgu , Daegu 41566 , Republic of Korea
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39
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Cai Z, Liu B, Zou X, Cheng HM. Chemical Vapor Deposition Growth and Applications of Two-Dimensional Materials and Their Heterostructures. Chem Rev 2018; 118:6091-6133. [PMID: 29384374 DOI: 10.1021/acs.chemrev.7b00536] [Citation(s) in RCA: 440] [Impact Index Per Article: 73.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Two-dimensional (2D) materials have attracted increasing research interest because of the abundant choice of materials with diverse and tunable electronic, optical, and chemical properties. Moreover, 2D material based heterostructures combining several individual 2D materials provide unique platforms to create an almost infinite number of materials and show exotic physical phenomena as well as new properties and applications. To achieve these high expectations, methods for the scalable preparation of 2D materials and 2D heterostructures of high quality and low cost must be developed. Chemical vapor deposition (CVD) is a powerful method which may meet the above requirements, and has been extensively used to grow 2D materials and their heterostructures in recent years, despite several challenges remaining. In this review of the challenges in the CVD growth of 2D materials, we highlight recent advances in the controlled growth of single crystal 2D materials, with an emphasis on semiconducting transition metal dichalcogenides. We provide insight into the growth mechanisms of single crystal 2D domains and the key technologies used to realize wafer-scale growth of continuous and homogeneous 2D films which are important for practical applications. Meanwhile, strategies to design and grow various kinds of 2D material based heterostructures are thoroughly discussed. The applications of CVD-grown 2D materials and their heterostructures in electronics, optoelectronics, sensors, flexible devices, and electrocatalysis are also discussed. Finally, we suggest solutions to these challenges and ideas concerning future developments in this emerging field.
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Affiliation(s)
- Zhengyang Cai
- Shenzhen Geim Graphene Center (SGC), Tsinghua-Berkeley Shenzhen Institute (TBSI) , Tsinghua University , Shenzhen , Guangdong 518055 , People's Republic of China
| | - Bilu Liu
- Shenzhen Geim Graphene Center (SGC), Tsinghua-Berkeley Shenzhen Institute (TBSI) , Tsinghua University , Shenzhen , Guangdong 518055 , People's Republic of China
| | - Xiaolong Zou
- Shenzhen Geim Graphene Center (SGC), Tsinghua-Berkeley Shenzhen Institute (TBSI) , Tsinghua University , Shenzhen , Guangdong 518055 , People's Republic of China
| | - Hui-Ming Cheng
- Shenzhen Geim Graphene Center (SGC), Tsinghua-Berkeley Shenzhen Institute (TBSI) , Tsinghua University , Shenzhen , Guangdong 518055 , People's Republic of China.,Shenyang National Laboratory for Materials Sciences, Institute of Metal Research , Chinese Academy of Sciences , Shenyang , Liaoning 110016 , People's Republic of China.,Center of Excellence in Environmental Studies (CEES) , King Abdulaziz University , Jeddah 21589 , Saudi Arabia
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40
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Zhou J, Jena P. Giant Valley Splitting and Valley Polarized Plasmonics in Group V Transition-Metal Dichalcogenide Monolayers. J Phys Chem Lett 2017; 8:5764-5770. [PMID: 29129083 DOI: 10.1021/acs.jpclett.7b02507] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Two-dimensional group VI transition-metal dichalcogenides (TMDs) provide a promising platform to encode and manipulate quantum information in the valleytronics. However, the two valleys are energetically degenerate, protected by time-reversal symmetry (TRS). To lift this degeneracy, one needs to break the TRS by either applying an external magnetic field or using a magnetic rare-earth oxide substrate. Here, we predict a different strategy to achieve this goal. We propose that the ferromagnetic group V TMD monolayer, in which the TRS is intrinsically broken, can produce a larger valley and spin splitting. A polarized ZnS(0001) surface is also used as a substrate, which shifts the valleys to the low-energy regime (near the Fermi level). Moreover, by calculating its collective electronic excitation behaviors, we show that such a system hosts a giant valley polarized terahertz plasmonics. Our results demonstrate a new way to design and use valleytronic devices, which are both fundamentally and technologically significant.
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Affiliation(s)
- Jian Zhou
- Physics Department, Virginia Commonwealth University , Richmond, Virginia 23284, United States
| | - Puru Jena
- Physics Department, Virginia Commonwealth University , Richmond, Virginia 23284, United States
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41
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Avsar A, Unuchek D, Liu J, Sanchez OL, Watanabe K, Taniguchi T, Özyilmaz B, Kis A. Optospintronics in Graphene via Proximity Coupling. ACS NANO 2017; 11:11678-11686. [PMID: 29068661 PMCID: PMC5707628 DOI: 10.1021/acsnano.7b06800] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2017] [Accepted: 10/25/2017] [Indexed: 05/30/2023]
Abstract
The observation of micrometer size spin relaxation makes graphene a promising material for applications in spintronics requiring long-distance spin communication. However, spin dependent scatterings at the contact/graphene interfaces affect the spin injection efficiencies and hence prevent the material from achieving its full potential. While this major issue could be eliminated by nondestructive direct optical spin injection schemes, graphene's intrinsically low spin-orbit coupling strength and optical absorption place an obstacle in their realization. We overcome this challenge by creating sharp artificial interfaces between graphene and WSe2 monolayers. Application of circularly polarized light activates the spin-polarized charge carriers in the WSe2 layer due to its spin-coupled valley-selective absorption. These carriers diffuse into the superjacent graphene layer, transport over a 3.5 μm distance, and are finally detected electrically using Co/h-BN contacts in a nonlocal geometry. Polarization-dependent measurements confirm the spin origin of the nonlocal signal. We also demonstrate that such signal is absent if graphene is contacted to bilayer WSe2 where the inversion symmetry is restored.
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Affiliation(s)
- Ahmet Avsar
- Electrical
Engineering Institute and Institute of Materials Science and Engineering, École Polytechnique Fédérale
de Lausanne (EPFL), Lausanne CH 1015, Switzerland
| | - Dmitrii Unuchek
- Electrical
Engineering Institute and Institute of Materials Science and Engineering, École Polytechnique Fédérale
de Lausanne (EPFL), Lausanne CH 1015, Switzerland
| | - Jiawei Liu
- Centre
for Advanced 2D Materials, National University
of Singapore, Singapore 117542, Singapore
| | - Oriol Lopez Sanchez
- Electrical
Engineering Institute and Institute of Materials Science and Engineering, École Polytechnique Fédérale
de Lausanne (EPFL), Lausanne CH 1015, Switzerland
| | - Kenji Watanabe
- National
Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- National
Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Barbaros Özyilmaz
- Centre
for Advanced 2D Materials, National University
of Singapore, Singapore 117542, Singapore
| | - Andras Kis
- Electrical
Engineering Institute and Institute of Materials Science and Engineering, École Polytechnique Fédérale
de Lausanne (EPFL), Lausanne CH 1015, Switzerland
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42
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Zhang ZZ, Song XX, Luo G, Deng GW, Mosallanejad V, Taniguchi T, Watanabe K, Li HO, Cao G, Guo GC, Nori F, Guo GP. Electrotunable artificial molecules based on van der Waals heterostructures. SCIENCE ADVANCES 2017; 3:e1701699. [PMID: 29062893 PMCID: PMC5650488 DOI: 10.1126/sciadv.1701699] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 09/25/2017] [Indexed: 06/02/2023]
Abstract
Quantum confinement has made it possible to detect and manipulate single-electron charge and spin states. The recent focus on two-dimensional (2D) materials has attracted significant interests on possible applications to quantum devices, including detecting and manipulating either single-electron charging behavior or spin and valley degrees of freedom. However, the most popular model systems, consisting of tunable double-quantum-dot molecules, are still extremely difficult to realize in these materials. We show that an artificial molecule can be reversibly formed in atomically thin MoS2 sandwiched in hexagonal boron nitride, with each artificial atom controlled separately by electrostatic gating. The extracted values for coupling energies at different regimes indicate a single-electron transport behavior, with the coupling strength between the quantum dots tuned monotonically. Moreover, in the low-density regime, we observe a decrease of the conductance with magnetic field, suggesting the observation of Coulomb blockade weak anti-localization. Our experiments demonstrate for the first time the realization of an artificial quantum-dot molecule in a gated MoS2 van der Waals heterostructure, which could be used to investigate spin-valley physics. The compatibility with large-scale production, gate controllability, electron-hole bipolarity, and new quantum degrees of freedom in the family of 2D materials opens new possibilities for quantum electronics and its applications.
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Affiliation(s)
- Zhuo-Zhi Zhang
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xiang-Xiang Song
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Gang Luo
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Guang-Wei Deng
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Vahid Mosallanejad
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Takashi Taniguchi
- National Institute for Materials Science, Namiki 1-1, Ibaraki 305-0044, Japan
| | - Kenji Watanabe
- National Institute for Materials Science, Namiki 1-1, Ibaraki 305-0044, Japan
| | - Hai-Ou Li
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Gang Cao
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Guang-Can Guo
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Franco Nori
- CEMS, RIKEN, Wako-shi, Saitama 351-0198, Japan
- Department of Physics, University of Michigan, Ann Arbor, MI 48109–1040, USA
| | - Guo-Ping Guo
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
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43
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Liu P, Xiang B. 2D hetero-structures based on transition metal dichalcogenides: fabrication, properties and applications. Sci Bull (Beijing) 2017; 62:1148-1161. [PMID: 36659346 DOI: 10.1016/j.scib.2017.08.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 08/01/2017] [Accepted: 08/03/2017] [Indexed: 01/21/2023]
Abstract
Recently, two dimensional transition metal dichalcogenides MX2 (M=Mo, W, etc; X=S, Se, Te) have ignited immense interests because of their unique structural and physical properties for the potential applications in the nano-optoelectronics, valley-spintronics etc. In terms of the structural compatibility and van der Waals interaction, two dimensional (2D) MX2 layers can be fabricated into various lateral and vertical hetero-structures. The atomically-thin hetero-structures comprising different layered MX2 provide a new platform for exploring fundamental physics and device technologies with unprecedented phenomenon and extraordinary functionalities. In this review, we report the recent progress about the fabrication, properties and applications of 2D hetero-structures based on transition metal dichalcogenides.
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Affiliation(s)
- Ping Liu
- Department of Materials Science & Engineering, CAS Key Lab of Materials for Energy Conversion, and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Bin Xiang
- Department of Materials Science & Engineering, CAS Key Lab of Materials for Energy Conversion, and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei 230026, China.
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44
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Liu J, Hou WJ, Cheng C, Fu HX, Sun JT, Meng S. Intrinsic valley polarization of magnetic VSe 2 monolayers. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:255501. [PMID: 28516897 DOI: 10.1088/1361-648x/aa6e6e] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Intrinsic valley polarization can be obtained in VSe2 monolayers with broken inversion symmetry and time reversal symmetry. First-principles investigations reveal that the magnitude of the valley splitting in magnetic VSe2 induced by spin-orbit coupling reaches as high as 78.2 meV and can be linearly tuned by biaxial strain. Besides conventional polarized light, hole doping or illumination with light of proper frequency can offer effective routes to realize valley polarization. Moreover, spin-orbit coupling in monolayer VSe2 breaks not only the valley degeneracy but also the three-fold rotational symmetry in band structure. The intrinsic and tunable valley splitting and the breaking of optical isotropy bring additional benefits to valleytronic and optoelectronic applications.
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Affiliation(s)
- Jian Liu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
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Zhong D, Seyler KL, Linpeng X, Cheng R, Sivadas N, Huang B, Schmidgall E, Taniguchi T, Watanabe K, McGuire MA, Yao W, Xiao D, Fu KMC, Xu X. Van der Waals engineering of ferromagnetic semiconductor heterostructures for spin and valleytronics. SCIENCE ADVANCES 2017; 3:e1603113. [PMID: 28580423 PMCID: PMC5451195 DOI: 10.1126/sciadv.1603113] [Citation(s) in RCA: 257] [Impact Index Per Article: 36.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 04/03/2017] [Indexed: 05/22/2023]
Abstract
The integration of magnetic material with semiconductors has been fertile ground for fundamental science as well as of great practical interest toward the seamless integration of information processing and storage. We create van der Waals heterostructures formed by an ultrathin ferromagnetic semiconductor CrI3 and a monolayer of WSe2. We observe unprecedented control of the spin and valley pseudospin in WSe2, where we detect a large magnetic exchange field of nearly 13 T and rapid switching of the WSe2 valley splitting and polarization via flipping of the CrI3 magnetization. The WSe2 photoluminescence intensity strongly depends on the relative alignment between photoexcited spins in WSe2 and the CrI3 magnetization, because of ultrafast spin-dependent charge hopping across the heterostructure interface. The photoluminescence detection of valley pseudospin provides a simple and sensitive method to probe the intriguing domain dynamics in the ultrathin magnet, as well as the rich spin interactions within the heterostructure.
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Affiliation(s)
- Ding Zhong
- Department of Physics, University of Washington, Seattle, WA 98195, USA
| | - Kyle L. Seyler
- Department of Physics, University of Washington, Seattle, WA 98195, USA
| | - Xiayu Linpeng
- Department of Physics, University of Washington, Seattle, WA 98195, USA
| | - Ran Cheng
- Department of Physics, Carnegie Mellon University, Pittsburg, PA 15213, USA
| | - Nikhil Sivadas
- Department of Physics, Carnegie Mellon University, Pittsburg, PA 15213, USA
| | - Bevin Huang
- Department of Physics, University of Washington, Seattle, WA 98195, USA
| | - Emma Schmidgall
- Department of Physics, University of Washington, Seattle, WA 98195, USA
| | - Takashi Taniguchi
- National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Kenji Watanabe
- National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Michael A. McGuire
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Wang Yao
- Department of Physics and Center of Theoretical and Computational Physics, University of Hong Kong, Hong Kong, China
| | - Di Xiao
- Department of Physics, Carnegie Mellon University, Pittsburg, PA 15213, USA
| | - Kai-Mei C. Fu
- Department of Physics, University of Washington, Seattle, WA 98195, USA
- Department of Electrical Engineering, University of Washington, Seattle, WA 98195, USA
| | - Xiaodong Xu
- Department of Physics, University of Washington, Seattle, WA 98195, USA
- Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195, USA
- Corresponding author.
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Electrical spin injection and detection in molybdenum disulfide multilayer channel. Nat Commun 2017; 8:14947. [PMID: 28387252 PMCID: PMC5385572 DOI: 10.1038/ncomms14947] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 02/15/2017] [Indexed: 12/05/2022] Open
Abstract
Molybdenum disulfide has recently emerged as a promising two-dimensional semiconducting material for nano-electronic, opto-electronic and spintronic applications. However, the demonstration of an electron spin transport through a semiconducting MoS2 channel remains challenging. Here we show the evidence of the electrical spin injection and detection in the conduction band of a multilayer MoS2 semiconducting channel using a two-terminal spin-valve configuration geometry. A magnetoresistance around 1% has been observed through a 450 nm long, 6 monolayer thick MoS2 channel with a Co/MgO tunnelling spin injector and detector. It is found that keeping a good balance between the interface resistance and channel resistance is mandatory for the observation of the two-terminal magnetoresistance. Moreover, the electron spin-relaxation is found to be greatly suppressed in the multilayer MoS2 channel with an in-plane spin polarization. The long spin diffusion length (approximately ∼235 nm) could open a new avenue for spintronic applications using multilayer transition metal dichalcogenides. MoS2 is a promising two-dimensional candidate for opto-electronic and spintronic applications. Here, the authors report electrical spin injection and detection in a few-layered MoS2 channel, demonstrating that the spin diffusion length is at least 235 nm in MoS2 conduction band.
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