1
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Ağırcan H, Convertino D, Rossi A, Martini L, Pace S, Mishra N, Küster K, Starke U, Kartal Şireli G, Coletti C, Forti S. Determination and investigation of defect domains in multi-shape monolayer tungsten disulfide. NANOSCALE ADVANCES 2024; 6:2850-2859. [PMID: 38817435 PMCID: PMC11134227 DOI: 10.1039/d4na00125g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Accepted: 04/15/2024] [Indexed: 06/01/2024]
Abstract
Single-layer tungsten disulfide (WS2) is among the most widely investigated two-dimensional materials. Synthesizing it over large areas would enable the exploitation of its appealing optical and electronic properties in industrial applications. However, defects of different nature, concentration and distribution profoundly affect the optical as well as the electronic properties of this crystal. Controlling the defect density distribution can be an effective way to tailor the local dielectric environment and therefore the electronic properties of the system. In this work we investigate the defects in single-layer WS2, grown in different shapes by liquid phase chemical vapor deposition, where the concentration of certain defect species can be controlled by the growth conditions. The properties of the material are surveyed by means of optical spectroscopy, photoelectron spectroscopy and Kelvin probe force microscopy. We determine the chemical nature of the defects and study their influence on the optical and electronic properties of WS2. This work contributes to the understanding of the microscopic nature of the intrinsic defects in WS2, helping the development of defect-based technologies which rely on the control and engineering of defects in dielectric 2D crystals.
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Affiliation(s)
- H Ağırcan
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia Piazza San Silvestro 12 I-56127 Pisa Italy
- Department of Metallurgical & Materials Engineering Istanbul Technical University 34469 Maslak Istanbul Turkey
| | - D Convertino
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia Piazza San Silvestro 12 I-56127 Pisa Italy
| | - A Rossi
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia Piazza San Silvestro 12 I-56127 Pisa Italy
- Graphene Labs, Istituto Italiano di Tecnologia Via Morego 30 16163 Genova Italy
| | - L Martini
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia Piazza San Silvestro 12 I-56127 Pisa Italy
| | - S Pace
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia Piazza San Silvestro 12 I-56127 Pisa Italy
- Graphene Labs, Istituto Italiano di Tecnologia Via Morego 30 16163 Genova Italy
| | - N Mishra
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia Piazza San Silvestro 12 I-56127 Pisa Italy
- Graphene Labs, Istituto Italiano di Tecnologia Via Morego 30 16163 Genova Italy
| | - K Küster
- Max-Planck-Institut für Festkörperforschung Heisenbergstr. 1 70569 Stuttgart Germany
| | - U Starke
- Max-Planck-Institut für Festkörperforschung Heisenbergstr. 1 70569 Stuttgart Germany
| | - G Kartal Şireli
- Department of Metallurgical & Materials Engineering Istanbul Technical University 34469 Maslak Istanbul Turkey
| | - C Coletti
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia Piazza San Silvestro 12 I-56127 Pisa Italy
- Graphene Labs, Istituto Italiano di Tecnologia Via Morego 30 16163 Genova Italy
| | - S Forti
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia Piazza San Silvestro 12 I-56127 Pisa Italy
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2
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Li Z, Liu J, Rasmita A, Zhang Z, Gao W, Chia EEM. Room-Temperature Geometrical Circular Photocurrent in Few-Layer MoS 2. NANO LETTERS 2024; 24:5952-5957. [PMID: 38726903 DOI: 10.1021/acs.nanolett.4c00057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2024]
Abstract
Valleytronics, i.e., the manipulation of the valley degree of freedom, offers a promising path for energy-efficient electronics. One of the key milestones in this field is the room-temperature manipulation of the valley information in thick-layered material. Using scanning photocurrent microscopy, we achieve this milestone by observing a geometrically dependent circular photocurrent in a few-layer molybdenum disulfide (MoS2) under normal incidence. Such an observation shows that the system symmetry is lower than that of bulk MoS2 material, preserving the optical chirality-valley correspondence. Moreover, the circular photocurrent polarity can be reversed by applying electrical bias. We propose a model where the observed photocurrent results from the symmetry breaking and the built-in field at the electrode-sample interface. Our results show that the valley information is still retained even in thick-layered MoS2 at room temperature and opens up new opportunities for exploiting the valley index through interface engineering in multilayer valleytronics devices.
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Affiliation(s)
- Ziqi Li
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
| | - Jiayun Liu
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
| | - Abdullah Rasmita
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
| | - Zhaowei Zhang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
- Department of Physics, School of Sciences, Great Bay University, Dongguan 523000, China
- Great Bay Institute for Advanced Study, Dongguan 523000, China
| | - Weibo Gao
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
- The Photonics Institute and Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore 637371, Singapore
- Centre for Quantum Technologies, National University of Singapore, Singapore 117543, Singapore
| | - Elbert E M Chia
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
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3
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Barth I, Deckart M, Conteduca D, Arruda G, Hayran Z, Pasko S, Krotkus S, Heuken M, Monticone F, Krauss TF, Martins ER, Wang Y. Lasing from a Large-Area 2D Material Enabled by a Dual-Resonance Metasurface. ACS NANO 2024; 18:12897-12904. [PMID: 38710615 PMCID: PMC11112975 DOI: 10.1021/acsnano.4c00547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 04/10/2024] [Accepted: 04/24/2024] [Indexed: 05/08/2024]
Abstract
Semiconducting transition metal dichalcogenides (TMDs) have gained significant attention as a gain medium for nanolasers, owing to their unique ability to be easily placed and stacked on virtually any substrate. However, the atomically thin nature of the active material in existing TMD lasers and the limited size due to mechanical exfoliation presents a challenge, as their limited output power makes it difficult to distinguish between true laser operation and other "laser-like" phenomena. Here, we present room temperature lasing from a large-area tungsten disulfide (WS2) monolayer, grown by a wafer-scale chemical vapor deposition (CVD) technique. The monolayer is placed on a dual-resonance dielectric metasurface with a rectangular lattice designed to enhance both absorption and emission, resulting in an ultralow threshold operation (threshold well below 1 W/cm2). We provide a thorough study of the laser performance, paying special attention to directionality, output power, and spatial coherence. Notably, our lasers demonstrated a coherence length of over 30 μm, which is several times greater than what has been reported for 2D material lasers so far. Our realization of a single-mode laser from a CVD-grown monolayer presents exciting opportunities for integration and the development of real-world applications.
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Affiliation(s)
- Isabel Barth
- School
of Physics, Engineering and Technology, University of York, York YO10 5DD, U.K.
| | - Manuel Deckart
- School
of Physics, Engineering and Technology, University of York, York YO10 5DD, U.K.
| | - Donato Conteduca
- School
of Physics, Engineering and Technology, University of York, York YO10 5DD, U.K.
| | - Guilherme
S. Arruda
- São
Carlos School of Engineering, Department of Electrical and Computer
Engineering, University of São Paulo,
São, Carlos-SP 13566-590, Brazil
| | - Zeki Hayran
- School
of Electrical and Computer Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Sergej Pasko
- AIXTRON
SE, Dornkaulstraße.
2, Herzogenrath 52134, Germany
| | | | - Michael Heuken
- AIXTRON
SE, Dornkaulstraße.
2, Herzogenrath 52134, Germany
| | - Francesco Monticone
- School
of Electrical and Computer Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Thomas F. Krauss
- School
of Physics, Engineering and Technology, University of York, York YO10 5DD, U.K.
| | - Emiliano R. Martins
- São
Carlos School of Engineering, Department of Electrical and Computer
Engineering, University of São Paulo,
São, Carlos-SP 13566-590, Brazil
| | - Yue Wang
- School
of Physics, Engineering and Technology, University of York, York YO10 5DD, U.K.
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4
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Liu A, Zhang X, Liu Z, Li Y, Peng X, Li X, Qin Y, Hu C, Qiu Y, Jiang H, Wang Y, Li Y, Tang J, Liu J, Guo H, Deng T, Peng S, Tian H, Ren TL. The Roadmap of 2D Materials and Devices Toward Chips. NANO-MICRO LETTERS 2024; 16:119. [PMID: 38363512 PMCID: PMC10873265 DOI: 10.1007/s40820-023-01273-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 10/30/2023] [Indexed: 02/17/2024]
Abstract
Due to the constraints imposed by physical effects and performance degradation, silicon-based chip technology is facing certain limitations in sustaining the advancement of Moore's law. Two-dimensional (2D) materials have emerged as highly promising candidates for the post-Moore era, offering significant potential in domains such as integrated circuits and next-generation computing. Here, in this review, the progress of 2D semiconductors in process engineering and various electronic applications are summarized. A careful introduction of material synthesis, transistor engineering focused on device configuration, dielectric engineering, contact engineering, and material integration are given first. Then 2D transistors for certain electronic applications including digital and analog circuits, heterogeneous integration chips, and sensing circuits are discussed. Moreover, several promising applications (artificial intelligence chips and quantum chips) based on specific mechanism devices are introduced. Finally, the challenges for 2D materials encountered in achieving circuit-level or system-level applications are analyzed, and potential development pathways or roadmaps are further speculated and outlooked.
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Affiliation(s)
- Anhan Liu
- School of Integrated Circuits and Beijing National Research Center for Information Science and Technology (BNRist), Tsinghua University, Beijing, 100049, People's Republic of China
| | - Xiaowei Zhang
- School of Integrated Circuits and Beijing National Research Center for Information Science and Technology (BNRist), Tsinghua University, Beijing, 100049, People's Republic of China
| | - Ziyu Liu
- School of Microelectronics, Fudan University, Shanghai, 200433, People's Republic of China
| | - Yuning Li
- School of Electronic and Information Engineering, Beijing Jiaotong University, Beijing, 100044, People's Republic of China
| | - Xueyang Peng
- High-Frequency High-Voltage Device and Integrated Circuits R&D Center, Institute of Microelectronics, Chinese Academy of Sciences, Beijing, 100029, People's Republic of China
- School of Integrated Circuits, University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Xin Li
- State Key Laboratory of Dynamic Measurement Technology, Shanxi Province Key Laboratory of Quantum Sensing and Precision Measurement, North University of China, Taiyuan, 030051, People's Republic of China
| | - Yue Qin
- State Key Laboratory of Dynamic Measurement Technology, Shanxi Province Key Laboratory of Quantum Sensing and Precision Measurement, North University of China, Taiyuan, 030051, People's Republic of China
| | - Chen Hu
- High-Frequency High-Voltage Device and Integrated Circuits R&D Center, Institute of Microelectronics, Chinese Academy of Sciences, Beijing, 100029, People's Republic of China
- School of Integrated Circuits, University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Yanqing Qiu
- High-Frequency High-Voltage Device and Integrated Circuits R&D Center, Institute of Microelectronics, Chinese Academy of Sciences, Beijing, 100029, People's Republic of China
- School of Integrated Circuits, University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Han Jiang
- School of Microelectronics, Fudan University, Shanghai, 200433, People's Republic of China
| | - Yang Wang
- School of Microelectronics, Fudan University, Shanghai, 200433, People's Republic of China
| | - Yifan Li
- School of Integrated Circuits and Beijing National Research Center for Information Science and Technology (BNRist), Tsinghua University, Beijing, 100049, People's Republic of China
| | - Jun Tang
- State Key Laboratory of Dynamic Measurement Technology, Shanxi Province Key Laboratory of Quantum Sensing and Precision Measurement, North University of China, Taiyuan, 030051, People's Republic of China
| | - Jun Liu
- State Key Laboratory of Dynamic Measurement Technology, Shanxi Province Key Laboratory of Quantum Sensing and Precision Measurement, North University of China, Taiyuan, 030051, People's Republic of China
| | - Hao Guo
- State Key Laboratory of Dynamic Measurement Technology, Shanxi Province Key Laboratory of Quantum Sensing and Precision Measurement, North University of China, Taiyuan, 030051, People's Republic of China.
| | - Tao Deng
- School of Electronic and Information Engineering, Beijing Jiaotong University, Beijing, 100044, People's Republic of China.
| | - Songang Peng
- High-Frequency High-Voltage Device and Integrated Circuits R&D Center, Institute of Microelectronics, Chinese Academy of Sciences, Beijing, 100029, People's Republic of China.
- IMECAS-HKUST-Joint Laboratory of Microelectronics, Beijing, 100029, People's Republic of China.
| | - He Tian
- School of Integrated Circuits and Beijing National Research Center for Information Science and Technology (BNRist), Tsinghua University, Beijing, 100049, People's Republic of China.
| | - Tian-Ling Ren
- School of Integrated Circuits and Beijing National Research Center for Information Science and Technology (BNRist), Tsinghua University, Beijing, 100049, People's Republic of China.
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5
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Huang W, De-Eknamkul C, Ren Y, Cubukcu E. Directing valley-polarized emission of 3 L WS 2 by photonic crystal with directional circular dichroism. OPTICS EXPRESS 2024; 32:6076-6084. [PMID: 38439318 PMCID: PMC11018336 DOI: 10.1364/oe.510027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 01/10/2024] [Accepted: 01/19/2024] [Indexed: 03/06/2024]
Abstract
The valley degree of freedom that results from broken inversion symmetry in two-dimensional (2D) transition-metal dichalcogenides (TMDCs) has sparked a lot of interest due to its huge potential in information processing. In this experimental work, to optically address the valley-polarized emission from three-layer (3 L) thick WS2 at room temperature, we employ a SiN photonic crystal slab that has two sets of holes in a square lattice that supports directional circular dichroism engendered by delocalized guided mode resonances. By perturbatively breaking the inversion symmetry of the photonic crystal slab, we can simultaneously manipulate s and p components of the radiating field so that these resonances correspond to circularly polarized emission. The emission of excitons from distinct valleys is coupled into different radiative channels and hence separated in the farfield. This directional exciton emission from selective valleys provides a potential route for valley-polarized light emitters, which lays the groundwork for future valleytronic devices.
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Affiliation(s)
- Wenzhuo Huang
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093-0407, USA
| | - Chawina De-Eknamkul
- Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093-0448, USA
| | - Yundong Ren
- Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093-0448, USA
| | - Ertugrul Cubukcu
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093-0407, USA
- Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093-0448, USA
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6
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Lee H, Kim YB, Ryu JW, Kim S, Bae J, Koo Y, Jang D, Park KD. Recent progress of exciton transport in two-dimensional semiconductors. NANO CONVERGENCE 2023; 10:57. [PMID: 38102309 PMCID: PMC10724105 DOI: 10.1186/s40580-023-00404-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 11/20/2023] [Indexed: 12/17/2023]
Abstract
Spatial manipulation of excitonic quasiparticles, such as neutral excitons, charged excitons, and interlayer excitons, in two-dimensional semiconductors offers unique capabilities for a broad range of optoelectronic applications, encompassing photovoltaics, exciton-integrated circuits, and quantum light-emitting systems. Nonetheless, their practical implementation is significantly restricted by the absence of electrical controllability for neutral excitons, short lifetime of charged excitons, and low exciton funneling efficiency at room temperature, which remain a challenge in exciton transport. In this comprehensive review, we present the latest advancements in controlling exciton currents by harnessing the advanced techniques and the unique properties of various excitonic quasiparticles. We primarily focus on four distinct control parameters inducing the exciton current: electric fields, strain gradients, surface plasmon polaritons, and photonic cavities. For each approach, the underlying principles are introduced in conjunction with its progression through recent studies, gradually expanding their accessibility, efficiency, and functionality. Finally, we outline the prevailing challenges to fully harness the potential of excitonic quasiparticles and implement practical exciton-based optoelectronic devices.
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Affiliation(s)
- Hyeongwoo Lee
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Yong Bin Kim
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Jae Won Ryu
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Sujeong Kim
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Jinhyuk Bae
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Yeonjeong Koo
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Donghoon Jang
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Kyoung-Duck Park
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea.
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7
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Chen Y, Feng J, Huang Y, Chen W, Su R, Ghosh S, Hou Y, Xiong Q, Qiu CW. Compact spin-valley-locked perovskite emission. NATURE MATERIALS 2023; 22:1065-1070. [PMID: 37081172 DOI: 10.1038/s41563-023-01531-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 03/13/2023] [Indexed: 05/03/2023]
Abstract
Circularly polarized light sources with free-space directional emission play a key role in chiroptics1, spintronics2, valleytronics3 and asymmetric photocatalysis4. However, conventional approaches fail to simultaneously realize pure circular polarization, high directionality and large emission angles in a compact emitter. Metal-halide perovskite semiconductors are promising light emitters5-8, but the absence of an intrinsic spin-locking mechanism results in poor emission chirality. Further, device integration has undermined the efficiency and directionality of perovskite chiral emitters. Here we realize compact spin-valley-locked perovskite emitting metasurfaces where spin-dependent geometric phases are imparted into bound states in the continuum via Brillouin zone folding, and thus, photons with different spins are selectively addressed to opposite valleys. Employing this approach, chiral purity of 0.91 and emission angle of 41.0° are simultaneously achieved, with a beam divergence angle of 1.6°. With this approach, we envisage the realization of chiral light-emitting diodes, as well as the on-chip generation of entangled photon pairs.
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Affiliation(s)
- Yang Chen
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
- Chinese Academy of Sciences Key Laboratory of Mechanical Behavior and Design of Materials, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, People's Republic of China
| | - Jiangang Feng
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore.
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore.
| | - Yuqing Huang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore
- Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping, Sweden
| | - Weijin Chen
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Rui Su
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore
| | - Sanjib Ghosh
- Beijing Academy of Quantum Information Sciences, Beijing, People's Republic of China
| | - Yi Hou
- Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore, Singapore
- Solar Energy Research Institute of Singapore (SERIS), National University of Singapore, Singapore, Singapore
| | - Qihua Xiong
- Beijing Academy of Quantum Information Sciences, Beijing, People's Republic of China.
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, People's Republic of China.
- Frontier Science Center for Quantum Information, Beijing, People's Republic of China.
| | - Cheng-Wei Qiu
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore.
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8
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Li M, Gao M, Zhang Q, Yang Y. Valley-dependent vortex emission from exciton-polariton in non-centrosymmetric transition metal dichalcogenide metasurfaces. OPTICS EXPRESS 2023; 31:19622-19631. [PMID: 37381373 DOI: 10.1364/oe.490067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 05/18/2023] [Indexed: 06/30/2023]
Abstract
Transition metal dichalcogenides (TMDs) have attracted great attention in valleytronics. Owing to the giant valley coherence at room temperature, valley pseudospin of TMDs open a new degree of freedom to encode and process binary information. The valley pseudospin only exists in non-centrosymmetric TMDs (e.g., monolayer or 3R-stacked multilayer), which is prohibited in conventional centrosymmetric 2H-stacked crystals. Here, we propose a general recipe to generate valley-dependent vortex beams by using a mix-dimensional TMD metasurface composed of nanostructured 2H-stacked TMD crystals and monolayer TMDs. Such an ultrathin TMD metasurface involves a momentum-space polarization vortex around bound states in the continuum (BICs), which can simultaneously achieve strong coupling (i.e., form exciton polaritons) and valley-locked vortex emission. Moreover, we report that a full 3R-stacked TMD metasurface can also reveal the strong-coupling regime with an anti-crossing pattern and a Rabi splitting of 95 meV. The Rabi splitting can be precisely controlled by geometrically shaping the TMD metasurface. Our results provide an ultra-compact TMD platform for controlling and structuring valley exciton polariton, in which the valley information is linked with the topological charge of vortex emission, which may advance valleytronic, polaritonic, and optoelectronic applications.
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9
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Hu W, Liu C, Dai X, Wen S, Xiang Y. Second harmonic generation by matching the phase distributions of topological corner and edge states. OPTICS LETTERS 2023; 48:2341-2344. [PMID: 37126269 DOI: 10.1364/ol.489194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Second harmonic generation (SHG) in topological photonic crystals is chiefly concerned with frequency conversion between the same topological states. However, little attention has been paid to the effect of coupling between different topological states on the SHG. In this study, we propose a method for achieving optimal SHG in a topological cavity by matching the phase distributions of the electric fields of the topological corner state (TCS) and topological edge state (TES). Our results show that the intrinsic efficiency can be improved when the phase distributions of the fundamental wave within the TCS and the second harmonic wave within the TES have the same symmetry. Otherwise, conversion efficiency will be greatly inhibited. With this method, we achieved an optimal intrinsic efficiency of 0.165%. Such a platform may enable the development of integrated nanoscale light sources and on-chip frequency converters.
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10
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Luo W, Whetten BG, Kravtsov V, Singh A, Yang Y, Huang D, Cheng X, Jiang T, Belyanin A, Raschke MB. Ultrafast Nanoimaging of Electronic Coherence of Monolayer WSe 2. NANO LETTERS 2023; 23:1767-1773. [PMID: 36827496 DOI: 10.1021/acs.nanolett.2c04536] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Transition-metal dichalcogenides (TMDs) have demonstrated a wide range of novel photonic, optoelectronic, and correlated electron phenomena for more than a decade. However, the coherent dynamics of their excitons, including possibly long dephasing times and their sensitivity to spatial heterogeneities, are still poorly understood. Here we implement adiabatic plasmonic nanofocused four-wave mixing (FWM) to image the coherent electron dynamics in monolayer WSe2. We observe nanoscale heterogeneities at room temperature with dephasing ranging from T2 ≲ 5 to T2 ≳ 60 fs on length scales of 50-100 nm. We further observe a counterintuitive anticorrelation between FWM intensity and T2, with the weakest FWM emission at locations of longest coherence. We interpret this behavior as a nonlocal nano-optical interplay between spatial coherence of the nonlinear polarization and disorder-induced scattering. The results highlight the challenges associated with heterogeneities in TMDs limiting their photophysical properties, yet also the potential of their novel nonlinear optical phenomena.
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Affiliation(s)
- Wenjin Luo
- MOE Key Laboratory of Advanced Micro-Structured Materials, Shanghai Frontiers Science Center of Digital Optics, Institute of Precision Optical Engineering, and School of Physics Science and Engineering, Tongji University, Shanghai 200092, People's Republic of China
- Department of Physics and JILA, University of Colorado, Boulder, Colorado 80309, United States
| | - Benjamin G Whetten
- Department of Physics and JILA, University of Colorado, Boulder, Colorado 80309, United States
| | - Vasily Kravtsov
- School of Physics and Engineering, ITMO University, Saint Petersburg 197101, Russia
| | - Ashutosh Singh
- Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, United States
| | - Yibo Yang
- Department of Computer Science, University of Colorado, Boulder, Colorado 80309, United States
| | - Di Huang
- MOE Key Laboratory of Advanced Micro-Structured Materials, Shanghai Frontiers Science Center of Digital Optics, Institute of Precision Optical Engineering, and School of Physics Science and Engineering, Tongji University, Shanghai 200092, People's Republic of China
| | - Xinbin Cheng
- MOE Key Laboratory of Advanced Micro-Structured Materials, Shanghai Frontiers Science Center of Digital Optics, Institute of Precision Optical Engineering, and School of Physics Science and Engineering, Tongji University, Shanghai 200092, People's Republic of China
| | - Tao Jiang
- MOE Key Laboratory of Advanced Micro-Structured Materials, Shanghai Frontiers Science Center of Digital Optics, Institute of Precision Optical Engineering, and School of Physics Science and Engineering, Tongji University, Shanghai 200092, People's Republic of China
| | - Alexey Belyanin
- Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, United States
| | - Markus B Raschke
- Department of Physics and JILA, University of Colorado, Boulder, Colorado 80309, United States
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11
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Mushtaq A, Yang X, Gao J. Unveiling room temperature upconversion photoluminescence in monolayer WSe 2. OPTICS EXPRESS 2022; 30:45212-45220. [PMID: 36522928 DOI: 10.1364/oe.471027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 11/15/2022] [Indexed: 06/17/2023]
Abstract
Upconversion photoluminescence (UPL) is a phenomenon describing an anti-Stokes process where the emitted photons have higher energy than the absorbed incident photons. Transition metal dichalcogenides (TMDCs) with strong photon-exciton interactions represent a fascinating platform for studying the anti-Stokes UPL process down to the monolayer thickness limit. Herein, we demonstrate room-temperature UPL emission in monolayer WSe2 with broadband near-infrared excitation. The measured excitation power dependence of UPL intensity at various upconversion energy gains unveils two distinguished upconversion mechanisms, including the one-photon involved multiphonon-assisted UPL process and the two-photon absorption (TPA) induced UPL process. In the phonon-assisted UPL regime, the observed exponential decay of UPL intensity with the increased energy gain is attributed to the decreased phonon population. Furthermore, valley polarization properties of UPL emission with circular polarization excitation is investigated. The demonstrated results will advance future photon upconversion applications based on monolayer TMDCs such as night vision, semiconductor laser cooling, and bioimaging.
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12
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Room-temperature electrical control of polarization and emission angle in a cavity-integrated 2D pulsed LED. Nat Commun 2022; 13:4884. [PMID: 35985999 PMCID: PMC9391484 DOI: 10.1038/s41467-022-32292-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 07/25/2022] [Indexed: 11/08/2022] Open
Abstract
Devices based on two-dimensional (2D) semiconductors hold promise for the realization of compact and versatile on-chip interconnects between electrical and optical signals. Although light emitting diodes (LEDs) are fundamental building blocks for integrated photonics, the fabrication of light sources made of bulk materials on complementary metal-oxide-semiconductor (CMOS) circuits is challenging. While LEDs based on van der Waals heterostructures have been realized, the control of the emission properties necessary for information processing remains limited. Here, we show room-temperature electrical control of the location, directionality and polarization of light emitted from a 2D LED operating at MHz frequencies. We integrate the LED in a planar cavity to couple the polariton emission angle and polarization to the in-plane exciton momentum, controlled by a lateral voltage. These findings demonstrate the potential of TMDCs as fast, compact and tunable light sources, promising for the realization of electrically driven polariton lasers. 2D semiconductors offer a promising platform for the realization of compact and CMOS-compatible optoelectronic components. Here, the authors report the realization of light-emitting diodes based on 2D WSe2 integrated with a planar cavity, showing the electrical control of the emission angle and polarization at room temperature.
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13
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Zheng SW, Wang D, Wang HY, Wang H, Chen X, Zhao LY, Wang L, Li XB, Sun HB. Spin-Valley Depolarization in van der Waals Heterostructures. J Phys Chem Lett 2022; 13:5501-5507. [PMID: 35695739 DOI: 10.1021/acs.jpclett.2c01414] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The appearance of van der Waals heterostructures offers a new solution to valleytronics. Here, we observe the spin-valley depolarization process of electrons and holes in type-II MoS2-WSe2 heterostructures simultaneously for the first time by valley-resolved broad-band femtosecond pump-probe experiments. The different depolarization paths between electrons and holes make them have different spin-valley polarization lifetimes. The spin-valley depolarization pathway of holes is mainly dominated by a phonon-assisted intervalley scattering process, while intra- and intervalley coupling can trigger additional depolarization pathways for electrons. The hole polarization lifetime can be further prolonged to more than three times in trilayer heterostructure 2MoS2-WSe2. For MoS2-WS2 that has strong orbital hybridization of Mo and W atoms, both electrons and holes lose the spin-valley polarization extremely soon after charge separation, behaving similarly to intraexcitons in a monolayer. Our work advances the basic understanding of spin-valley depolarization of van der Waals heterostructures and facilitates the effort toward longer lifetime valleytronic devices for information transfer and storage applications.
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Affiliation(s)
- Shu-Wen Zheng
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Dan Wang
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06511, United States
| | - Hai-Yu Wang
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Hai Wang
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Xin Chen
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Le-Yi Zhao
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Lei Wang
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Xian-Bin Li
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Hong-Bo Sun
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Haidian, Beijing 100084, China
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14
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Huang L, Krasnok A, Alú A, Yu Y, Neshev D, Miroshnichenko AE. Enhanced light-matter interaction in two-dimensional transition metal dichalcogenides. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2022; 85:046401. [PMID: 34939940 DOI: 10.1088/1361-6633/ac45f9] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 12/16/2021] [Indexed: 05/27/2023]
Abstract
Two-dimensional (2D) transition metal dichalcogenide (TMDC) materials, such as MoS2, WS2, MoSe2, and WSe2, have received extensive attention in the past decade due to their extraordinary electronic, optical and thermal properties. They evolve from indirect bandgap semiconductors to direct bandgap semiconductors while their layer number is reduced from a few layers to a monolayer limit. Consequently, there is strong photoluminescence in a monolayer (1L) TMDC due to the large quantum yield. Moreover, such monolayer semiconductors have two other exciting properties: large binding energy of excitons and valley polarization. These properties make them become ideal materials for various electronic, photonic and optoelectronic devices. However, their performance is limited by the relatively weak light-matter interactions due to their atomically thin form factor. Resonant nanophotonic structures provide a viable way to address this issue and enhance light-matter interactions in 2D TMDCs. Here, we provide an overview of this research area, showcasing relevant applications, including exotic light emission, absorption and scattering features. We start by overviewing the concept of excitons in 1L-TMDC and the fundamental theory of cavity-enhanced emission, followed by a discussion on the recent progress of enhanced light emission, strong coupling and valleytronics. The atomically thin nature of 1L-TMDC enables a broad range of ways to tune its electric and optical properties. Thus, we continue by reviewing advances in TMDC-based tunable photonic devices. Next, we survey the recent progress in enhanced light absorption over narrow and broad bandwidths using 1L or few-layer TMDCs, and their applications for photovoltaics and photodetectors. We also review recent efforts of engineering light scattering, e.g., inducing Fano resonances, wavefront engineering in 1L or few-layer TMDCs by either integrating resonant structures, such as plasmonic/Mie resonant metasurfaces, or directly patterning monolayer/few layers TMDCs. We then overview the intriguing physical properties of different van der Waals heterostructures, and their applications in optoelectronic and photonic devices. Finally, we draw our opinion on potential opportunities and challenges in this rapidly developing field of research.
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Affiliation(s)
- Lujun Huang
- School of Engineering and Information Technology, University of New South Wales, Canberra, ACT, 2600, Australia
| | - Alex Krasnok
- Department of Electrical and Computer Engineering, Florida International University, Miami, FL 33174, United States of America
| | - Andrea Alú
- Photonics Initiative, Advanced Science Research Center, City University of New York, New York, NY 10031, United States of America
- Physics Program, Graduate Center, City University of New York, New York, NY 10016, United States of America
| | - Yiling Yu
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States of America
| | - Dragomir Neshev
- ARC Centre of Excellence for Transformative Meta-Optical Systems (TMOS), Department of Electronic Materials Engineering, Research School of Physics, The Australian National University, Canberra, ACT 2601, Australia
| | - Andrey E Miroshnichenko
- School of Engineering and Information Technology, University of New South Wales, Canberra, ACT, 2600, Australia
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15
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Tian J, Adamo G, Liu H, Klein M, Han S, Liu H, Soci C. Optical Rashba Effect in a Light-Emitting Perovskite Metasurface. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2109157. [PMID: 35045198 DOI: 10.1002/adma.202109157] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 12/13/2021] [Indexed: 06/14/2023]
Abstract
The Rashba effect, i.e., the splitting of electronic spin-polarized bands in the momentum space of a crystal with broken inversion symmetry, has enabled the realization of spin-orbitronic devices, in which spins are manipulated by spin-orbit coupling. In optics, where the helicity of light polarization represents the spin degree of freedom for spin-momentum coupling, the optical Rashba effect is manifested by the splitting of optical states with opposite chirality in the momentum space. Previous realizations of the optical Rashba effect relied on passive devices determining the surface plasmon or light propagation inside nanostructures, or the directional emission of chiral luminescence when hybridized with light-emitting media. An active device underpinned by the optical Rashba effect is demonstrated here, in which a monolithic halide perovskite metasurface emits highly directional chiral photoluminescence. An all-dielectric metasurface design with broken in-plane inversion symmetry is directly embossed into the high-refractive-index, light-emitting perovskite film, yielding a degree of circular polarization of photoluminescence of 60% at room temperature.
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Affiliation(s)
- Jingyi Tian
- Centre for Disruptive Photonic Technologies, TPI, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
| | - Giorgio Adamo
- Centre for Disruptive Photonic Technologies, TPI, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
| | - Hailong Liu
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Singapore, 138634, Singapore
| | - Maciej Klein
- Centre for Disruptive Photonic Technologies, TPI, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
| | - Song Han
- Centre for Disruptive Photonic Technologies, TPI, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
| | - Hong Liu
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Singapore, 138634, Singapore
| | - Cesare Soci
- Centre for Disruptive Photonic Technologies, TPI, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
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16
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Kim S, Woo BH, An SC, Lim Y, Seo IC, Kim DS, Yoo S, Park QH, Jun YC. Topological Control of 2D Perovskite Emission in the Strong Coupling Regime. NANO LETTERS 2021; 21:10076-10085. [PMID: 34843262 DOI: 10.1021/acs.nanolett.1c03853] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Momentum space topology can be exploited to manipulate radiation in real space. Here we demonstrate topological control of 2D perovskite emission in the strong coupling regime via polaritonic bound states in the continuum (BICs). Topological polarization singularities (polarization vortices and circularly polarized eigenstates) are observed at room temperature by measuring the Stokes parameters of photoluminescence in momentum space. Particularly, in symmetry-broken structures, a very large degree of circular polarization (DCP) of ∼0.835 is achieved in the perovskite emission, which is the largest in perovskite materials to our knowledge. In the strong coupling regime, lower polariton modes shift to the low-loss spectral region, resulting in strong emission enhancement and large DCP. Our reciprocity analysis reveals that DCP is limited by material absorption at the emission wavelength. Polaritonic BICs based on 2D perovskite materials combine unique topological features with exceptional material properties and may become a promising platform for active nanophotonic devices.
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Affiliation(s)
- Seongheon Kim
- Department of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Byung Hoon Woo
- Department of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Soo-Chan An
- Department of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Yeonsoo Lim
- Department of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - In Cheol Seo
- Department of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Dai-Sik Kim
- Department of Physics, UNIST, Ulsan 44919, Republic of Korea
| | - SeokJae Yoo
- Department of Physics, Inha University, Incheon 22212, Republic of Korea
| | - Q-Han Park
- Department of Physics, Korea University, Seoul 02841, Republic of Korea
| | - Young Chul Jun
- Department of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
- Graduate School of Semiconductor Materials and Devices Engineering, UNIST, Ulsan 44919, Republic of Korea
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17
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Chen PG, Li Z, Qi Y, Lo TW, Wang S, Jin W, Wong KY, Fan S, Zayats AV, Lei D. Long-Range Directional Routing and Spatial Selection of High-Spin-Purity Valley Trion Emission in Monolayer WS 2. ACS NANO 2021; 15:18163-18171. [PMID: 34730338 DOI: 10.1021/acsnano.1c06955] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Valley-dependent excitation and emission in transition metal dichalcogenides (TMDCs) have recently emerged as a new avenue for optical data manipulation, quantum optical technologies, and chiral photonics. The valley-polarized electronic states can be optically addressed through photonic spin-orbit interaction of excitonic emission, typically with plasmonic nanostructures, but their performance is limited by the low quantum yield of neutral excitons in TMDC multilayers and the large Ohmic loss of plasmonic systems. Here, we demonstrate a valleytronic system based on the trion emission in high-quantum-yield WS2 monolayers chirally coupled to a low-loss microfiber. The integrated system uses the spin properties of the waveguided modes to achieve long-range directional routing of valley excitations and also provides an approach to selectively address valley-dependent emission from different spatial locations around the microfiber. This valleytronic interface can be integrated with fiber communication devices, allowing for merging valley polarization and chiral photonics as an alternative mechanism for optical information transport and manipulation in classical and quantum regimes.
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Affiliation(s)
- Pei-Gang Chen
- Department of Materials Science and Engineering, The City University of Hong Kong, Hong Kong 999077, China
| | - Zhiyong Li
- State Key Laboratory of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong 999077, China
| | - Yun Qi
- Department of Electrical Engineering, The Hong Kong Polytechnic University, Hong Kong 999077, China
| | - Tsz Wing Lo
- Department of Materials Science and Engineering, The City University of Hong Kong, Hong Kong 999077, China
| | - Shubo Wang
- Department of Physics, City University of Hong Kong, Hong Kong 999077, China
| | - Wei Jin
- Department of Electrical Engineering, The Hong Kong Polytechnic University, Hong Kong 999077, China
| | - Kwok-Yin Wong
- State Key Laboratory of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong 999077, China
| | - Shanhui Fan
- Department of Electrical Engineering and Ginzton Laboratory, Stanford University, Stanford, California 94305-4088, United States
| | - Anatoly V Zayats
- Department of Physics and London Centre for Nanotechnology, King's College London, Strand, London WC2R 2LS, U.K
| | - Dangyuan Lei
- Department of Materials Science and Engineering, The City University of Hong Kong, Hong Kong 999077, China
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18
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Zeng Y, Hu G, Liu K, Tang Z, Qiu CW. Dynamics of Topological Polarization Singularity in Momentum Space. PHYSICAL REVIEW LETTERS 2021; 127:176101. [PMID: 34739271 DOI: 10.1103/physrevlett.127.176101] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 09/21/2021] [Indexed: 06/13/2023]
Abstract
The polarization singularity in momentum space has recently been discovered as a new class of topological signatures of Bloch modes in photonic crystal slabs concerning the far-field radiations, beyond its near-field description with widely explored topological band theory. Bound states in the continuum (BICs) in photonic crystal slabs are demonstrated as vortex eigenpolarization singularities in momentum space and the circular polarization points (C points) are also obtained based on BICs, opening up more possibilities for exotic light scattering and various topological phenomena of singular optics. Here, focusing on the nondegenerate bands, we report the generation to annihilation of two pairs of C points in momentum space in the photonic crystal slabs with inversion symmetry but broken up-down mirror symmetry. Interestingly, as the C points evolve with the structure parameter, we find two merging processes of C points, where an accidental at-Γ BIC and unidirectional radiative resonances with leaky channels of drastically different radiative lifetime emerge. The whole evolution is governed by the global charge conservation and the sum of topological charges equals to zero. Our findings suggest a novel recipe for dynamic generation and manipulation of various polarization singularities in momentum space and might shed new light to control the resonant and topological properties of light-matter interactions.
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Affiliation(s)
- Yixuan Zeng
- College of Computer Science and Electronic Engineering, Hunan University, Changsha 410082, China
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583, Singapore
| | - Guangwei Hu
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583, Singapore
| | - Kaipeng Liu
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583, Singapore
| | - Zhixiang Tang
- College of Computer Science and Electronic Engineering, Hunan University, Changsha 410082, China
| | - Cheng-Wei Qiu
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583, Singapore
- National University of Singapore Suzhou Research Institute, Suzhou 215125, China
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19
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Zheng SW, Wang HY, Wang L, Luo Y, Gao BR, Sun HB. Observation of robust charge transfer under strain engineering in two-dimensional MoS 2-WSe 2 heterostructures. NANOSCALE 2021; 13:14081-14088. [PMID: 34477689 DOI: 10.1039/d1nr02014e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Strain is one of the effective ways to modulate the band structure of monolayer transition metal dichalcogenides (TMDCs), which has been reported in theoretical and steady-state spectroscopic studies. However, the strain effects on the charge transfer processes in TMDC heterostructures have not been experimentally addressed thus far. Here, we systematically investigate the strain-mediated transient spectral evolutions corresponding to excitons at band-edge and higher energy states for monolayer MoS2 and monolayer WSe2. It is demonstrated that Γ and K valleys in monolayer WSe2 and monolayer MoS2 present different strain responses, according to the broadband femtosecond pump-probe experimental results. It is further observed that the resulting band offset changes tuned by applied tensile strains in MoS2-WSe2 heterostructures would not affect the band-edge electron transfer profiles, where only monolayer WSe2 is excited. From a flexible optoelectronic applications perspective, the robust charge transfer under strain engineering in TMDC heterostructures is very advantageous.
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Affiliation(s)
- Shu-Wen Zheng
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China.
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20
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Yao Q, Bie YQ, Chen J, Li J, Li F, Cao Z. Anapole enhanced on-chip routing of spin-valley photons in 2D materials for silicon integrated optical communication. OPTICS LETTERS 2021; 46:4080-4083. [PMID: 34469944 DOI: 10.1364/ol.433457] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 07/16/2021] [Indexed: 06/13/2023]
Abstract
Controlling the propagation direction of polarized light is crucial for optical communications and functional optical components. However, all-dielectric on-chip technology exploiting valley photon emission in transition metal dichalcogenides with enhanced emission has yet to be fully explored. Here, we report a design for enhancing valley emission and manipulating valley photon propagation based on degenerate non-radiating anapole states. By placing circularly polarized dipoles on top of a C4 symmetric cross-slotted silicon disk, the rotating anapole state is excited with a Purcell factor up to two orders. In addition, the photon coupled to the preferred direction of the waveguide are about 2 times larger than that to the opposite direction. Our design could pave the way for realizing on-chip valley-dependent optical communication.
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21
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Giant Photoluminescence Enhancement and Carrier Dynamics in MoS 2 Bilayers with Anomalous Interlayer Coupling. NANOMATERIALS 2021; 11:nano11081994. [PMID: 34443826 PMCID: PMC8398585 DOI: 10.3390/nano11081994] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 07/31/2021] [Accepted: 08/02/2021] [Indexed: 11/23/2022]
Abstract
Fundamental researches and explorations based on transition metal dichalcogenides (TMDCs) mainly focus on their monolayer counterparts, where optical densities are limited owing to the atomic monolayer thickness. Photoluminescence (PL) yield in bilayer TMDCs is much suppressed owing to indirect-bandgap properties. Here, optical properties are explored in artificially twisted bilayers of molybdenum disulfide (MoS2). Anomalous interlayer coupling and resultant giant PL enhancement are firstly observed in MoS2 bilayers, related to the suspension of the top layer material and independent of twisted angle. Moreover, carrier dynamics in MoS2 bilayers with anomalous interlayer coupling are revealed with pump-probe measurements, and the secondary rising behavior in pump-probe signal of B-exciton resonance, originating from valley depolarization of A-exciton, is firstly reported and discussed in this work. These results lay the groundwork for future advancement and applications beyond TMDCs monolayers.
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22
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Li T, Chen A, Fan L, Zheng M, Wang J, Lu G, Zhao M, Cheng X, Li W, Liu X, Yin H, Shi L, Zi J. Photonic-dispersion neural networks for inverse scattering problems. LIGHT, SCIENCE & APPLICATIONS 2021; 10:154. [PMID: 34315850 PMCID: PMC8316458 DOI: 10.1038/s41377-021-00600-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 07/10/2021] [Accepted: 07/13/2021] [Indexed: 06/13/2023]
Abstract
Inferring the properties of a scattering objective by analyzing the optical far-field responses within the framework of inverse problems is of great practical significance. However, it still faces major challenges when the parameter range is growing and involves inevitable experimental noises. Here, we propose a solving strategy containing robust neural-networks-based algorithms and informative photonic dispersions to overcome such challenges for a sort of inverse scattering problem-reconstructing grating profiles. Using two typical neural networks, forward-mapping type and inverse-mapping type, we reconstruct grating profiles whose geometric features span hundreds of nanometers with nanometric sensitivity and several seconds of time consumption. A forward-mapping neural network with a parameters-to-point architecture especially stands out in generating analytical photonic dispersions accurately, featured by sharp Fano-shaped spectra. Meanwhile, to implement the strategy experimentally, a Fourier-optics-based angle-resolved imaging spectroscopy with an all-fixed light path is developed to measure the dispersions by a single shot, acquiring adequate information. Our forward-mapping algorithm can enable real-time comparisons between robust predictions and experimental data with actual noises, showing an excellent linear correlation (R2 > 0.982) with the measurements of atomic force microscopy. Our work provides a new strategy for reconstructing grating profiles in inverse scattering problems.
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Affiliation(s)
- Tongyu Li
- State Key Laboratory of Surface Physics, Key Laboratory of Micro- and Nano-Photonics Structures (Ministry of Education) and Department of Physics, Fudan University, Shanghai 200433, China
- Shanghai Engineering Research Center of Optical Metrology for Nano-fabrication (SERCOM), Shanghai 200433, China
| | - Ang Chen
- Shanghai Engineering Research Center of Optical Metrology for Nano-fabrication (SERCOM), Shanghai 200433, China
| | - Lingjie Fan
- State Key Laboratory of Surface Physics, Key Laboratory of Micro- and Nano-Photonics Structures (Ministry of Education) and Department of Physics, Fudan University, Shanghai 200433, China
- Shanghai Engineering Research Center of Optical Metrology for Nano-fabrication (SERCOM), Shanghai 200433, China
| | - Minjia Zheng
- State Key Laboratory of Surface Physics, Key Laboratory of Micro- and Nano-Photonics Structures (Ministry of Education) and Department of Physics, Fudan University, Shanghai 200433, China
- Shanghai Engineering Research Center of Optical Metrology for Nano-fabrication (SERCOM), Shanghai 200433, China
| | - Jiajun Wang
- State Key Laboratory of Surface Physics, Key Laboratory of Micro- and Nano-Photonics Structures (Ministry of Education) and Department of Physics, Fudan University, Shanghai 200433, China
- Shanghai Engineering Research Center of Optical Metrology for Nano-fabrication (SERCOM), Shanghai 200433, China
| | - Guopeng Lu
- Shanghai Engineering Research Center of Optical Metrology for Nano-fabrication (SERCOM), Shanghai 200433, China
| | - Maoxiong Zhao
- State Key Laboratory of Surface Physics, Key Laboratory of Micro- and Nano-Photonics Structures (Ministry of Education) and Department of Physics, Fudan University, Shanghai 200433, China
- Shanghai Engineering Research Center of Optical Metrology for Nano-fabrication (SERCOM), Shanghai 200433, China
| | - Xinbin Cheng
- Institute of Precision Optical Engineering, School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
| | - Wei Li
- National Institute of Metrology, Beijing 100029, China
| | - Xiaohan Liu
- State Key Laboratory of Surface Physics, Key Laboratory of Micro- and Nano-Photonics Structures (Ministry of Education) and Department of Physics, Fudan University, Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Haiwei Yin
- Shanghai Engineering Research Center of Optical Metrology for Nano-fabrication (SERCOM), Shanghai 200433, China
| | - Lei Shi
- State Key Laboratory of Surface Physics, Key Laboratory of Micro- and Nano-Photonics Structures (Ministry of Education) and Department of Physics, Fudan University, Shanghai 200433, China.
- Shanghai Engineering Research Center of Optical Metrology for Nano-fabrication (SERCOM), Shanghai 200433, China.
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China.
| | - Jian Zi
- State Key Laboratory of Surface Physics, Key Laboratory of Micro- and Nano-Photonics Structures (Ministry of Education) and Department of Physics, Fudan University, Shanghai 200433, China.
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China.
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Zhuo Z, Chen H, Huang J, Li S, Wang J, Ding K, Ni H, Niu Z, Jiang D, Dou X, Sun B. Self-Induced Dark States in Two-Dimensional Excitons. J Phys Chem Lett 2021; 12:3485-3489. [PMID: 33792330 DOI: 10.1021/acs.jpclett.1c00633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We have obtained an ultralong lifetime exciton emission in InAs/GaAs single quantum dots (QDs) when the QD films are transferred onto the Si substrate covered by Ag nanoparticles. It is found that when the separation distance from the QD layer (also the wetting layer) to the Ag nanoparticles is around 19 nm, the QD emission lifetime changes from approximately 1 to 2000 ns. A classical dipole oscillator model is used to quantitatively calculate the spontaneous radiation decay rate of the excitons in the wetting layer (WL), and the simulated calculation result is in good agreement with the experimental one, revealing that the long lifetime exciton emission is due to the existence of the dark state in the WL. The self-induced dark state stems from the destructive interference between the exciton emission field and the induced dipole field of the Ag nanoparticles.
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Affiliation(s)
- Zhiyao Zhuo
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hao Chen
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Junhui Huang
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shulun Li
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jian Wang
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kun Ding
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Haiqiao Ni
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhichuan Niu
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| | - Desheng Jiang
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Xiuming Dou
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Baoquan Sun
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
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Chen JH, Xiong YF, Xu F, Lu YQ. Silica optical fiber integrated with two-dimensional materials: towards opto-electro-mechanical technology. LIGHT, SCIENCE & APPLICATIONS 2021; 10:78. [PMID: 33854031 PMCID: PMC8046821 DOI: 10.1038/s41377-021-00520-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 03/14/2021] [Accepted: 03/29/2021] [Indexed: 05/27/2023]
Abstract
In recent years, the integration of graphene and related two-dimensional (2D) materials in optical fibers have stimulated significant advances in all-fiber photonics and optoelectronics. The conventional passive silica fiber devices with 2D materials are empowered for enhancing light-matter interactions and are applied for manipulating light beams in respect of their polarization, phase, intensity and frequency, and even realizing the active photo-electric conversion and electro-optic modulation, which paves a new route to the integrated multifunctional all-fiber optoelectronic system. This article reviews the fast-progress field of hybrid 2D-materials-optical-fiber for the opto-electro-mechanical devices. The challenges and opportunities in this field for future development are discussed.
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Affiliation(s)
- Jin-Hui Chen
- Institute of Electromagnetics and Acoustics, Xiamen University, Xiamen, 361005, China
- College of Engineering and Applied Sciences, National Laboratory of Solid State Microstructures and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Yi-Feng Xiong
- College of Engineering and Applied Sciences, National Laboratory of Solid State Microstructures and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Fei Xu
- College of Engineering and Applied Sciences, National Laboratory of Solid State Microstructures and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.
| | - Yan-Qing Lu
- College of Engineering and Applied Sciences, National Laboratory of Solid State Microstructures and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.
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25
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Li S, Wang H, Wang J, Chen H, Shao L. Control of light-valley interactions in 2D transition metal dichalcogenides with nanophotonic structures. NANOSCALE 2021; 13:6357-6372. [PMID: 33885520 DOI: 10.1039/d0nr08000d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Electronic valley in two-dimensional transition-metal dichalcogenides (2D TMDCs) offers a new degree of freedom for information storage and processing. The valley pseudospin can be optically encoded by photons with specific helicity, enabling the construction of electronic information devices with both high performance and low power consumption. Robust detection, manipulation and transport of the valley pseudospins at room temperature are still challenging because of the short lifetime of valley-polarized carriers and excitons. Integrating 2D TMDCs with nanophotonic objects such as plasmonic nanostructures provides a competitive solution to address the challenge. The research in this field is of practical interest and can also present rich physics of light-matter interactions. In this minireview, recent progress on using nanophotonic strategies to enhance the valley polarization degree, especially at room temperature, is highlighted. Open questions, major challenges, and interesting future developments in manipulating the valley information in 2D semiconductors with the help of nanophotonic structures will also be discussed.
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Affiliation(s)
- Shasha Li
- Beijing Computational Science Research Center, Beijing 100193, China.
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Tang Y, Hao H, Kang Y, Liu Q, Sui Y, Wei K, Cheng X, Jiang T. Distinctive Interfacial Charge Behavior and Versatile Photoresponse Performance in Isotropic/Anisotropic WS 2/ReS 2 Heterojunctions. ACS APPLIED MATERIALS & INTERFACES 2020; 12:53475-53483. [PMID: 33180451 DOI: 10.1021/acsami.0c14886] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Van der Waals (vdWs) heterostructures based on in-plane isotropic/anisotropic 2D-layered semiconducting materials have recently received wide attention because of their unique interlayer coupling properties and hold a bright future as building blocks for advanced photodetectors. However, a fundamental understanding of charge behavior inside this kind of heterostructure in the photoexcited state remains elusive. In this work, we carry out a systematic investigation into the photoinduced interfacial charge behavior in type-II WS2/ReS2 vertical heterostructures via polarization-dependent pump-probe microscopy. Benefiting from the distinctive (ultrafast and anisotropic) charge-transfer mechanisms, the photodetector based on the WS2/ReS2 heterojunction displays more superior optoelectronic properties compared to its constituents with diverse functionalities including moderate photoresponsivity, polarization sensitivity, and fast photoresponse speed. Additionally, this device can function as a self-driven photodetector without the external bias. These results of our work tangibly corroborate the intriguing interlayer interaction in in-plane isotropic/anisotropic heterostructures and are expected to shed light on designing balanced-performance multifunctional optoelectrical devices.
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Affiliation(s)
- Yuxiang Tang
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, P. R. China
| | - Hao Hao
- State Key Laboratory of High Performance Computing, College of Computer, National University of Defense Technology, Changsha 410073, P. R. China
| | - Yan Kang
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, P. R. China
| | - Qirui Liu
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, P. R. China
| | - Yizhen Sui
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, P. R. China
| | - Ke Wei
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, P. R. China
| | - Xiang'ai Cheng
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, P. R. China
| | - Tian Jiang
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, P. R. China
- Beijing Institude for Advanced Study, National University of Defense Technology, Beijing 100010, P. R. China
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