1
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Rossi A, Zipfel J, Maity I, Lorenzon M, Dandu M, Barré E, Francaviglia L, Regan EC, Zhang Z, Nie JH, Barnard ES, Watanabe K, Taniguchi T, Rotenberg E, Wang F, Lischner J, Raja A, Weber-Bargioni A. Anomalous Interlayer Exciton Diffusion in WS 2/WSe 2 Moiré Heterostructure. ACS NANO 2024; 18:18202-18210. [PMID: 38950893 PMCID: PMC11256890 DOI: 10.1021/acsnano.4c00015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2024] [Revised: 05/28/2024] [Accepted: 06/05/2024] [Indexed: 07/03/2024]
Abstract
Stacking van der Waals crystals allows for the on-demand creation of a periodic potential landscape to tailor the transport of quasiparticle excitations. We investigate the diffusion of photoexcited electron-hole pairs, or excitons, at the interface of WS2/WSe2 van der Waals heterostructure over a wide range of temperatures. We observe the appearance of distinct interlayer excitons for parallel and antiparallel stacking and track their diffusion through spatially and temporally resolved photoluminescence spectroscopy from 30 to 250 K. While the measured exciton diffusivity decreases with temperature, it surprisingly plateaus below 90 K. Our observations cannot be explained by classical models like hopping in the moiré potential. A combination of ab initio theory and molecular dynamics simulations suggests that low-energy phonons arising from the mismatched lattices of moiré heterostructures, also known as phasons, play a key role in describing and understanding this anomalous behavior of exciton diffusion. Our observations indicate that the moiré potential landscape is dynamic down to very low temperatures and that the phason modes can enable efficient transport of energy in the form of excitons.
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Affiliation(s)
- Antonio Rossi
- The
Molecular Foundry, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
- Advanced
Light Source, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
- Center
for Nanotechnology Innovation @ NEST, Instituto
Italiano di Tecnologia, 56127 Pisa, Italy
| | - Jonas Zipfel
- The
Molecular Foundry, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
| | - Indrajit Maity
- Imperial
College London, South Kensington Campus, London SW7 2AZ, U.K.
| | - Monica Lorenzon
- The
Molecular Foundry, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
| | - Medha Dandu
- The
Molecular Foundry, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
| | - Elyse Barré
- The
Molecular Foundry, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
| | - Luca Francaviglia
- The
Molecular Foundry, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
| | - Emma C. Regan
- Department
of Physics, University of California at
Berkeley, Berkeley, California 94720, United States
| | - Zuocheng Zhang
- Department
of Physics, University of California at
Berkeley, Berkeley, California 94720, United States
| | - Jacob H. Nie
- Department
of Physics, University of California at
Berkeley, Berkeley, California 94720, United States
- Department
of Physics, University of California at
Santa Barbara, Santa
Barbara, California 93106, United States
| | - Edward S. Barnard
- The
Molecular Foundry, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
| | - Kenji Watanabe
- Research
Center for Functional Materials, National
Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0047, Japan
| | - Takashi Taniguchi
- International
Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0047, Japan
| | - Eli Rotenberg
- Advanced
Light Source, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
| | - Feng Wang
- Department
of Physics, University of California at
Berkeley, Berkeley, California 94720, United States
| | - Johannes Lischner
- Imperial
College London, South Kensington Campus, London SW7 2AZ, U.K.
| | - Archana Raja
- The
Molecular Foundry, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
| | - Alexander Weber-Bargioni
- The
Molecular Foundry, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
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2
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Kang M, Kim SJ, Joo H, Koo Y, Lee H, Lee HS, Suh YD, Park KD. Nanoscale Manipulation of Exciton-Trion Interconversion in a MoSe 2 Monolayer via Tip-Enhanced Cavity-Spectroscopy. NANO LETTERS 2024; 24:279-286. [PMID: 38117534 DOI: 10.1021/acs.nanolett.3c03920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2023]
Abstract
Emerging light-matter interactions in metal-semiconductor hybrid platforms have attracted considerable attention due to their potential applications in optoelectronic devices. Here, we demonstrate plasmon-induced near-field manipulation of trionic responses in a MoSe2 monolayer using tip-enhanced cavity-spectroscopy (TECS). The surface plasmon-polariton mode on the Au nanowire can locally manipulate the exciton (X0) and trion (X-) populations of MoSe2. Furthermore, we reveal that surface charges significantly influence the emission and interconversion processes of X0 and X-. In the TECS configuration, the localized plasmon significantly affects the distributions of X0 and X- due to the modified radiative decay rate. Additionally, within the TECS cavity, the electric doping effect and hot electron generation enable dynamic interconversion between X0 and X- at the nanoscale. This work advances our understanding of plasmon-exciton-hot electron interactions in metal-semiconductor-metal hybrid structures, providing a foundation for an optimal trion-based nano-optoelectronic platform.
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Affiliation(s)
- Mingu Kang
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Su Jin Kim
- Department of Physics, Research Institute for Nanoscale Science and Technology, Chungbuk National University, Cheongju 28644, Republic of Korea
| | - Huitae Joo
- 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
| | - Hyeongwoo Lee
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Hyun Seok Lee
- Department of Physics, Research Institute for Nanoscale Science and Technology, Chungbuk National University, Cheongju 28644, Republic of Korea
| | - Yung Doug Suh
- Department of Chemistry and School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919 Republic of Korea
- Center for Multidimensional Carbon Materials (CMCM), Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea
| | - Kyoung-Duck Park
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
- Center for Multidimensional Carbon Materials (CMCM), Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea
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3
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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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4
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Luo W, Lawrie BJ, Puretzky AA, Tan Q, Gao H, Lingerfelt DB, Eichman G, Mcgee E, Swan AK, Liang L, Ling X. Imaging Strain-Localized Single-Photon Emitters in Layered GaSe below the Diffraction Limit. ACS NANO 2023. [PMID: 38044592 DOI: 10.1021/acsnano.3c05250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Nanoscale strain control of exciton funneling is an increasingly critical tool for the scalable production of single photon emitters (SPEs) in two-dimensional materials. However, conventional far-field optical microscopies remain constrained in spatial resolution by the diffraction limit and thus can provide only a limited description of nanoscale strain localization of SPEs. Here, we quantify the effects of nanoscale heterogeneous strain on the energy and brightness of GaSe SPEs on nanopillars with correlative cathodoluminescence, photoluminescence, and atomic force microscopy, supported by density functional theory simulations. We report the strain-localized SPEs have a broad range of emission wavelengths from 620 to 900 nm. We reveal substantial strain-controlled SPE wavelength tunability over a ∼100 nm spectral range and 2 orders of magnitude enhancement in the SPE brightness at the pillar center due to Type-I exciton funneling. In addition, we show that radiative biexciton cascade processes contribute to observed CL photon superbunching. Also, the GaSe SPEs show excellent stability, where their properties remain unchanged after electron beam exposure. We anticipate that this comprehensive study on the nanoscale strain control of two-dimensional SPEs will provide key insights to guide the development of truly deterministic quantum photonics.
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Affiliation(s)
- Weijun Luo
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Benjamin J Lawrie
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Alexander A Puretzky
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Qishuo Tan
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Hongze Gao
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - David B Lingerfelt
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Gage Eichman
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Edward Mcgee
- Department of Electrical Engineering, Boston University, Boston, Massachusetts 02215, United States
| | - Anna K Swan
- Department of Electrical Engineering, Boston University, Boston, Massachusetts 02215, United States
- The Photonics Center, Boston University, Boston, Massachusetts 02215, United States
| | - Liangbo Liang
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Xi Ling
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
- The Photonics Center, Boston University, Boston, Massachusetts 02215, United States
- Division of Materials Science and Engineering, Boston University, Boston, Massachusetts 02215, United States
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5
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Tenney SM, Tan LA, Tan X, Sonnleitner ML, Coffey B, Williams JA, Ronquillo R, Atallah TL, Ahmed T, Caram JR. Efficient 2D to 0D Energy Transfer in HgTe Nanoplatelet-Quantum Dot Heterostructures through High-Speed Exciton Diffusion. J Phys Chem Lett 2023; 14:9456-9463. [PMID: 37830914 DOI: 10.1021/acs.jpclett.3c02168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2023]
Abstract
Large area absorbers with localized defect emission are of interest for energy concentration via the antenna effect. Transfer between 2D and 0D quantum-confined structures is advantageous as it affords maximal lateral area antennas with continuously tunable emission. We report the quantum efficiency of energy transfer in in situ grown HgTe nanoplatelet (NPL)/quantum dot (QD) heterostructures to be near unity (>85%), while energy transfer in separately synthesized and well separated solutions of HgTe NPLs to QDs only reaches 47 ± 11% at considerably higher QD concentrations. Using Kinetic Monte Carlo simulations, we estimate an exciton diffusion constant of 1-10 cm2/s in HgTe NPLs, the same magnitude as that of 2D semiconductors. We also simulate in-solution energy transfer between NPLs and QDs, recovering an R-4 dependence consistent with 2D-0D near-field energy transfer even in randomly distributed NPL/QD mixtures. This highlights the advantage of NPLs 2D morphology and the efficiency of NPL/QD heterostructures and mixtures for energy harvesting.
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Affiliation(s)
- Stephanie M Tenney
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive, Los Angeles, California 90095-1569, United States
| | - Lauren A Tan
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive, Los Angeles, California 90095-1569, United States
| | - Xuanheng Tan
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive, Los Angeles, California 90095-1569, United States
| | - Mikayla L Sonnleitner
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive, Los Angeles, California 90095-1569, United States
| | - Belle Coffey
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive, Los Angeles, California 90095-1569, United States
| | - Jillian A Williams
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive, Los Angeles, California 90095-1569, United States
| | - Ricky Ronquillo
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive, Los Angeles, California 90095-1569, United States
| | - Timothy L Atallah
- Department of Chemistry and Biochemistry, Denison University, 500 West Loop, Granville, Ohio 43023, United States
| | - Tasnim Ahmed
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive, Los Angeles, California 90095-1569, United States
| | - Justin R Caram
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive, Los Angeles, California 90095-1569, United States
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6
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Zhu G, Zhang L, Li W, Shi X, Zou Z, Guo Q, Li X, Xu W, Jie J, Wang T, Du W, Xiong Q. Room-temperature high-speed electrical modulation of excitonic distribution in a monolayer semiconductor. Nat Commun 2023; 14:6701. [PMID: 37872139 PMCID: PMC10593816 DOI: 10.1038/s41467-023-42568-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Accepted: 10/16/2023] [Indexed: 10/25/2023] Open
Abstract
Excitons in monolayer semiconductors, benefitting from their large binding energies, hold great potential towards excitonic circuits bridging nano-electronics and photonics. However, achieving room-temperature ultrafast on-chip electrical modulation of excitonic distribution and flow in monolayer semiconductors is nontrivial. Here, utilizing lateral bias, we report high-speed electrical modulation of the excitonic distribution in a monolayer semiconductor junction at room temperature. The alternating charge trapping/detrapping at the two monolayer/electrode interfaces induces a non-uniform carrier distribution, leading to controlled in-plane spatial variations of excitonic populations, and mimicking a bias-driven excitonic flow. This modulation increases with the bias amplitude and eventually saturates, relating to the energetic distribution of trap density of states. The switching time of the modulation is down to 5 ns, enabling high-speed excitonic devices. Our findings reveal the trap-assisted exciton engineering in monolayer semiconductors and offer great opportunities for future two-dimensional excitonic devices and circuits.
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Affiliation(s)
- Guangpeng Zhu
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, PR China
| | - Lan Zhang
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, PR China
| | - Wenfei Li
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, PR China
| | - Xiuqi Shi
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, PR China
| | - Zhen Zou
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, PR China
| | - Qianqian Guo
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, PR China
| | - Xiang Li
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, PR China
| | - Weigao Xu
- Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, PR China
| | - Jiansheng Jie
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, PR China
| | - Tao Wang
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, PR China.
| | - Wei Du
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, PR China.
| | - Qihua Xiong
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, 100084, PR China
- Frontier Science Center for Quantum Information, Beijing, 100084, PR China
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, PR China
- Collaborative Innovation Center of Quantum Matter, Beijing, PR China
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7
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Weaver H, Went CM, Wong J, Jasrasaria D, Rabani E, Atwater HA, Ginsberg NS. Detecting, Distinguishing, and Spatiotemporally Tracking Photogenerated Charge and Heat at the Nanoscale. ACS NANO 2023; 17:19011-19021. [PMID: 37721430 PMCID: PMC10569093 DOI: 10.1021/acsnano.3c04607] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 09/13/2023] [Indexed: 09/19/2023]
Abstract
Since dissipative processes are ubiquitous in semiconductors, characterizing how electronic and thermal energy transduce and transport at the nanoscale is vital for understanding and leveraging their fundamental properties. For example, in low-dimensional transition metal dichalcogenides (TMDCs), excess heat generation upon photoexcitation is difficult to avoid since even with modest injected exciton densities exciton-exciton annihilation still occurs. Both heat and photoexcited electronic species imprint transient changes in the optical response of a semiconductor, yet the distinct signatures of each are difficult to disentangle in typical spectra due to overlapping resonances. In response, we employ stroboscopic optical scattering microscopy (stroboSCAT) to simultaneously map both heat and exciton populations in few-layer MoS2 on relevant nanometer and picosecond length- and time scales and with 100-mK temperature sensitivity. We discern excitonic contributions to the signal from heat by combining observations close to and far from exciton resonances, characterizing the photoinduced dynamics for each. Our approach is general and can be applied to any electronic material, including thermoelectrics, where heat and electronic observables spatially interplay, and it will enable direct and quantitative discernment of different types of coexisting energy without recourse to complex models or underlying assumptions.
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Affiliation(s)
- Hannah
L. Weaver
- Department
of Physics, University of California, Berkeley, California 94720, United States
| | - Cora M. Went
- Department
of Physics, California Institute of Technology, Pasadena, California 91125, United States
| | - Joeson Wong
- Department
of Applied Physics and Materials Science, California Institute of Technology, Pasadena, California 91125, United States
| | - Dipti Jasrasaria
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
| | - Eran Rabani
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
- Materials
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
- The
Sackler Center for Computational Molecular and Materials Science, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Harry A. Atwater
- Department
of Applied Physics and Materials Science, California Institute of Technology, Pasadena, California 91125, United States
| | - Naomi S. Ginsberg
- Department
of Physics, University of California, Berkeley, California 94720, United States
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
- Materials
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
- Molecular
Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Kavli
Energy NanoScience Institute, Berkeley, California 94720, United States
- STROBE
NSF Science & Technology Center, Berkeley, California 94720, United States
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8
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Del Águila AG, Wong YR, Wadgaonkar I, Fieramosca A, Liu X, Vaklinova K, Dal Forno S, Do TTH, Wei HY, Watanabe K, Taniguchi T, Novoselov KS, Koperski M, Battiato M, Xiong Q. Ultrafast exciton fluid flow in an atomically thin MoS 2 semiconductor. NATURE NANOTECHNOLOGY 2023; 18:1012-1019. [PMID: 37524907 DOI: 10.1038/s41565-023-01438-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 06/01/2023] [Indexed: 08/02/2023]
Abstract
Excitons (coupled electron-hole pairs) in semiconductors can form collective states that sometimes exhibit spectacular nonlinear properties. Here, we show experimental evidence of a collective state of short-lived excitons in a direct-bandgap, atomically thin MoS2 semiconductor whose propagation resembles that of a classical liquid as suggested by the nearly uniform photoluminescence through the MoS2 monolayer regardless of crystallographic defects and geometric constraints. The exciton fluid flows over ultralong distances (at least 60 μm) at a speed of ~1.8 × 107 m s-1 (~6% the speed of light). The collective phase emerges above a critical laser power, in the absence of free charges and below a critical temperature (usually Tc ≈ 150 K) approaching room temperature in hexagonal-boron-nitride-encapsulated devices. Our theoretical simulations suggest that momentum is conserved and local equilibrium is achieved among excitons; both these features are compatible with a fluid dynamics description of the exciton transport.
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Affiliation(s)
- Andrés Granados Del Águila
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore.
| | - Yi Ren Wong
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore
| | - Indrajit Wadgaonkar
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore
| | - Antonio Fieramosca
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore
| | - Xue Liu
- Institutes of Physical Science and Information Technology, Anhui University, Hefei, P.R. China
| | - Kristina Vaklinova
- Institute for Functional Intelligent Materials, National University of Singapore, Singapore, Singapore
| | - Stefano Dal Forno
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore
| | - T Thu Ha Do
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), Singapore, Republic of Singapore
| | - Ho Yi Wei
- Institute for Functional Intelligent Materials, National University of Singapore, Singapore, Singapore
- Department of Physics, National University of Singapore, Singapore, Singapore
| | - K Watanabe
- National Institute for Materials Science, Tsukuba, Japan
| | - T Taniguchi
- National Institute for Materials Science, Tsukuba, Japan
| | - Kostya S Novoselov
- Institute for Functional Intelligent Materials, National University of Singapore, Singapore, Singapore
- Department of Materials Science and Engineering, National University of Singapore, Singapore, Singapore
| | - Maciej Koperski
- Institute for Functional Intelligent Materials, National University of Singapore, Singapore, Singapore
- Department of Materials Science and Engineering, National University of Singapore, Singapore, Singapore
| | - Marco Battiato
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore
| | - Qihua Xiong
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, P.R. China.
- Frontier Science Center for Quantum Information, Beijing, P.R. China.
- Collaborative Innovation Center of Quantum Matter, Beijing, P.R. China.
- Beijing Academy of Quantum Information Sciences, Beijing, P.R. China.
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9
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Wagner K, Iakovlev ZA, Ziegler JD, Cuccu M, Taniguchi T, Watanabe K, Glazov MM, Chernikov A. Diffusion of Excitons in a Two-Dimensional Fermi Sea of Free Charges. NANO LETTERS 2023. [PMID: 37220259 DOI: 10.1021/acs.nanolett.2c03796] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Propagation of light-emitting quasiparticles is of central importance across the fields of condensed matter physics and nanomaterials science. We experimentally demonstrate diffusion of excitons in the presence of a continuously tunable Fermi sea of free charge carriers in a monolayer semiconductor. Light emission from tightly bound exciton states in electrically gated WSe2 monolayer is detected using spatially and temporally resolved microscopy. The measurements reveal a nonmonotonic dependence of the exciton diffusion coefficient on the charge carrier density in both electron and hole doped regimes. Supported by analytical theory describing exciton-carrier interactions in a dissipative system, we identify distinct regimes of elastic scattering and quasiparticle formation determining exciton diffusion. The crossover region exhibits a highly unusual behavior of an increasing diffusion coefficient with increasing carrier densities. Temperature-dependent diffusion measurements further reveal characteristic signatures of freely propagating excitonic complexes dressed by free charges with effective mobilities up to 3 × 103 cm2/(V s).
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Affiliation(s)
- Koloman Wagner
- Institute of Applied Physics and Wüzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany
- Department of Physics, University of Regensburg, 93053 Regensburg, Germany
| | | | - Jonas D Ziegler
- Institute of Applied Physics and Wüzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany
- Department of Physics, University of Regensburg, 93053 Regensburg, Germany
| | - Marzia Cuccu
- Institute of Applied Physics and Wüzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Ibaraki 305-004, Japan
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Ibaraki 305-004, Japan
| | | | - Alexey Chernikov
- Institute of Applied Physics and Wüzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany
- Department of Physics, University of Regensburg, 93053 Regensburg, Germany
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10
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Lee H, Koo Y, Kumar S, Jeong Y, Heo DG, Choi SH, Joo H, Kang M, Siddique RH, Kim KK, Lee HS, An S, Choo H, Park KD. All-optical control of high-purity trions in nanoscale waveguide. Nat Commun 2023; 14:1891. [PMID: 37045823 PMCID: PMC10097695 DOI: 10.1038/s41467-023-37481-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 03/20/2023] [Indexed: 04/14/2023] Open
Abstract
The generation of high-purity localized trions, dynamic exciton-trion interconversion, and their spatial modulation in two-dimensional (2D) semiconductors are building blocks for the realization of trion-based optoelectronic devices. Here, we present a method for the all-optical control of the exciton-to-trion conversion process and its spatial distributions in a MoS2 monolayer. We induce a nanoscale strain gradient in a 2D crystal transferred on a lateral metal-insulator-metal (MIM) waveguide and exploit propagating surface plasmon polaritons (SPPs) to localize hot electrons. These significantly increase the electrons and efficiently funnel excitons in the lateral MIM waveguide, facilitating complete exciton-to-trion conversion even at ambient conditions. Additionally, we modulate the SPP mode using adaptive wavefront shaping, enabling all-optical control of the exciton-to-trion conversion rate and trion distribution in a reversible manner. Our work provides a platform for harnessing excitonic quasiparticles efficiently in the form of trions at ambient conditions, enabling high-efficiency photoconversion.
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Affiliation(s)
- Hyeongwoo Lee
- 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
| | - Shailabh Kumar
- Department of Medical Engineering, California Institute of Technology (Caltech), Pasadena, CA, 91125, USA
- Meta Vision Lab, Samsung Advanced Institute of Technology (SAIT), Pasadena, CA, 91101, USA
| | - Yunjo Jeong
- Institute of Advanced Composite Materials, Korea Institute of Science and Technology, Jeonbuk, 55324, Republic of Korea
| | - Dong Gwon Heo
- Department of Physics, Research Institute of Physics and Chemistry, Jeonbuk National University, Jeonju, 54896, Republic of Korea
| | - Soo Ho Choi
- Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Suwon, 16419, Republic of Korea
| | - Huitae Joo
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Mingu Kang
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Radwanul Hasan Siddique
- Department of Medical Engineering, California Institute of Technology (Caltech), Pasadena, CA, 91125, USA
- Meta Vision Lab, Samsung Advanced Institute of Technology (SAIT), Pasadena, CA, 91101, USA
| | - Ki Kang Kim
- Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Suwon, 16419, Republic of Korea
- Department of Energy Science, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Hong Seok Lee
- Department of Physics, Research Institute of Physics and Chemistry, Jeonbuk National University, Jeonju, 54896, Republic of Korea.
| | - Sangmin An
- Department of Physics, Research Institute of Physics and Chemistry, Jeonbuk National University, Jeonju, 54896, Republic of Korea
| | - Hyuck Choo
- Department of Medical Engineering, California Institute of Technology (Caltech), Pasadena, CA, 91125, USA.
- Advanced Sensor Lab, Device Research Center, Samsung Advanced Institute of Technology (SAIT), Suwon, 16678, 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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11
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Nie X, Wu X, Wang Y, Ban S, Lei Z, Yi J, Liu Y, Liu Y. Surface acoustic wave induced phenomena in two-dimensional materials. NANOSCALE HORIZONS 2023; 8:158-175. [PMID: 36448884 DOI: 10.1039/d2nh00458e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Surface acoustic wave (SAW)-matter interaction provides a fascinating key for inducing and manipulating novel phenomena and functionalities in two-dimensional (2D) materials. The dynamic strain field and piezo-electric field associated with propagating SAWs determine the coherent manipulation and transduction between 2D excitons and phonons. Over the past decade, many intriguing acoustic-induced effects, including the acousto-electric effect, acousto-galvanic effect, acoustic Stark effect, acoustic Hall effect and acoustic exciton transport, have been reported experimentally. However, many more phenomena, such as the valley acousto-electric effect, valley acousto-electric Hall effect and acoustic spin Hall effect, were only theoretically proposed, the experimental verification of which are yet to be achieved. In this minireview, we attempt to overview the recent breakthrough of SAW-induced phenomena covering acoustic charge transport, acoustic exciton transport and modulation, and coherent acoustic phonons. Perspectives on the opportunities of the proposed SAW-induced phenomena, as well as open experimental challenges, are also discussed, attempting to offer some guidelines for experimentalists and theorists to explore the desired exotic properties and boost practical applications of 2D materials.
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Affiliation(s)
- Xuchen Nie
- Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control of Mechanical Structures, and Institute for Frontier Science, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China.
| | - Xiaoyue Wu
- Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control of Mechanical Structures, and Institute for Frontier Science, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China.
| | - Yang Wang
- Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control of Mechanical Structures, and Institute for Frontier Science, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China.
| | - Siyuan Ban
- Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control of Mechanical Structures, and Institute for Frontier Science, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China.
| | - Zhihao Lei
- Global Innovative Centre for Advanced Nanomaterials, College of Engineering, Science and Environment, The University of Newcastle, NSW, 2308, Australia
| | - Jiabao Yi
- Global Innovative Centre for Advanced Nanomaterials, College of Engineering, Science and Environment, The University of Newcastle, NSW, 2308, Australia
| | - Ying Liu
- College of Jincheng, Nanjing University of Aeronautics and Astronautics, Nanjing 211156, China.
| | - Yanpeng Liu
- Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control of Mechanical Structures, and Institute for Frontier Science, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China.
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12
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Zhou X, Satyabola D, Liu H, Jiang S, Qi X, Yu L, Lin S, Liu Y, Woodbury NW, Yan H. Two-Dimensional Excitonic Networks Directed by DNA Templates as an Efficient Model Light-Harvesting and Energy Transfer System. Angew Chem Int Ed Engl 2022; 61:e202211200. [PMID: 36288100 DOI: 10.1002/anie.202211200] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Indexed: 11/07/2022]
Abstract
Photosynthetic organisms organize discrete light-harvesting complexes into large-scale networks to facilitate efficient light collection and utilization. Inspired by nature, herein, synthetic DNA templates were used to direct the formation of dye aggregates with a cyanine dye, K21, into discrete branched photonic complexes, and two-dimensional (2D) excitonic networks. The DNA templates ranged from four-arm DNA tiles, ≈10 nm in each arm, to 2D wireframe DNA origami nanostructures with different geometries and varying dimensions up to 100×100 nm. These DNA-templated dye aggregates presented strongly coupled spectral features and delocalized exciton characteristics, enabling efficient photon collection and energy transfer. Compared to the discrete branched photonic systems templated on individual DNA tiles, the interconnected excitonic networks showed approximately a 2-fold increase in energy transfer efficiency. This bottom-up assembly strategy paves the way to create 2D excitonic systems with complex geometries and engineered energy pathways.
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Affiliation(s)
- Xu Zhou
- Center for Molecular Design and Biomimetics at the Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA
| | - Deeksha Satyabola
- Center for Molecular Design and Biomimetics at the Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA.,School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA
| | - Hao Liu
- Center for Molecular Design and Biomimetics at the Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA.,School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA
| | - Shuoxing Jiang
- Center for Molecular Design and Biomimetics at the Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA
| | - Xiaodong Qi
- Center for Molecular Design and Biomimetics at the Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA
| | - Lu Yu
- Center for Molecular Design and Biomimetics at the Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA.,School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA
| | - Su Lin
- Center for Molecular Design and Biomimetics at the Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA.,School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA
| | - Yan Liu
- School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA.,Center for Single Molecule Biophysics at the Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA
| | - Neal W Woodbury
- Center for Molecular Design and Biomimetics at the Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA.,School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA
| | - Hao Yan
- Center for Molecular Design and Biomimetics at the Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA.,School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA
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13
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Schedel C, Strauß F, Kohlschreiber P, Geladari O, Meixner AJ, Scheele M. Substrate effects on the speed limiting factor of WSe 2 photodetectors. Phys Chem Chem Phys 2022; 24:25383-25390. [PMID: 36239305 DOI: 10.1039/d2cp03364j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
We investigate the time-resolved photoelectric response of WSe2 crystals on glass and flexible polyimide substrates to determine the effect of a changed dielectric environment on the speed of the photodetectors. We show that varying the substrate material can alter the speed-limiting mechanism: while the detectors on polyimide are RC limited, those on glass are limited by slower excitonic diffusion processes. We attribute this to a shortening of the depletion layer at the metal electrode/WSe2 interface caused by the higher dielectric screening of glass compared to polyimide. The photodetectors on glass show a tunable bandwidth, which can be increased to 2.6 MHz with increasing the electric field.
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Affiliation(s)
- Christine Schedel
- Institute for Physical and Theoretical Chemistry, University of Tübingen, 72076 Tübingen, Germany
| | - Fabian Strauß
- Institute for Physical and Theoretical Chemistry, University of Tübingen, 72076 Tübingen, Germany
- Center for Light-Matter Interaction, Sensors and Analytics LISA+, University of Tübingen, 72076 Tübingen, Germany.
| | - Pia Kohlschreiber
- Institute for Physical and Theoretical Chemistry, University of Tübingen, 72076 Tübingen, Germany
| | - Olympia Geladari
- Institute for Physical and Theoretical Chemistry, University of Tübingen, 72076 Tübingen, Germany
| | - Alfred J Meixner
- Institute for Physical and Theoretical Chemistry, University of Tübingen, 72076 Tübingen, Germany
- Center for Light-Matter Interaction, Sensors and Analytics LISA+, University of Tübingen, 72076 Tübingen, Germany.
| | - Marcus Scheele
- Institute for Physical and Theoretical Chemistry, University of Tübingen, 72076 Tübingen, Germany
- Center for Light-Matter Interaction, Sensors and Analytics LISA+, University of Tübingen, 72076 Tübingen, Germany.
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14
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Kim JS, Maity N, Kim M, Fu S, Juneja R, Singh A, Akinwande D, Lin JF. Strain-Modulated Interlayer Charge and Energy Transfers in MoS 2/WS 2 Heterobilayer. ACS APPLIED MATERIALS & INTERFACES 2022; 14:46841-46849. [PMID: 36195978 DOI: 10.1021/acsami.2c10982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Excitonic properties in 2D heterobilayers are closely governed by charge transfer (CT) and excitonic energy transfer (ET) at van der Waals interfaces. Various means have been employed to modulate the interlayer CT and ET, including electrical gating and modifying interlayer spacing, but with limited extent in their controllability. Here, we report a novel method to modulate these transfers in the MoS2/WS2 heterobilayer by applying compressive strain under hydrostatic pressure. Raman and photoluminescence measurements, combined with density functional theory calculations, show pressure-enhanced interlayer interaction of the heterobilayer. Heterobilayer-to-monolayer photoluminescence intensity ratio (η) of WS2 decreases by five times up to ≈4 GPa, suggesting enhanced ET, whereas it increases by an order of magnitude at higher pressures and reaches almost unity. Theoretical calculations show that orbital switching and charge transfers in the heterobilayer's hybridized conduction band are responsible for the non-monotonic modulation of the transfers. Our findings provide a compelling approach toward effective mechanical control of CT and ET in 2D excitonic devices.
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Affiliation(s)
- Joon-Seok Kim
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois60208, United States
- Microelectronics Research Center, The University of Texas at Austin, Austin, Texas78758, United States
| | - Nikhilesh Maity
- Materials Research Centre, Indian Institute of Science, Bangalore560012, India
| | - Myungsoo Kim
- Microelectronics Research Center, The University of Texas at Austin, Austin, Texas78758, United States
| | - Suyu Fu
- Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, AustinTexas78712, United States
| | - Rinkle Juneja
- Materials Research Centre, Indian Institute of Science, Bangalore560012, India
| | - Abhishek Singh
- Materials Research Centre, Indian Institute of Science, Bangalore560012, India
| | - Deji Akinwande
- Microelectronics Research Center, The University of Texas at Austin, Austin, Texas78758, United States
| | - Jung-Fu Lin
- Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, AustinTexas78712, United States
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15
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Shi J, Wu X, Wu K, Zhang S, Sui X, Du W, Yue S, Liang Y, Jiang C, Wang Z, Wang W, Liu L, Wu B, Zhang Q, Huang Y, Qiu CW, Liu X. Giant Enhancement and Directional Second Harmonic Emission from Monolayer WS 2 on Silicon Substrate via Fabry-Pérot Micro-Cavity. ACS NANO 2022; 16:13933-13941. [PMID: 35984986 DOI: 10.1021/acsnano.2c03033] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Two-dimensional transition metal dichalcogenides (TMDs) possess large second-order optical nonlinearity, making them ideal candidates for miniaturized on-chip frequency conversion devices, all-optical interconnection, and optoelectronic integration components. However, limited by subnanometer thickness, the monolayer TMD exhibits low second harmonic generation (SHG) conversion efficiency (<0.1%) and poor directionality, which hinders their practical applications. Herein, we proposed a Fabry-Pérot (F-P) cavity formed by coupling an atomically thin WS2 film with a silicon hole matrix to enhance the SH emission. A maximum enhancement (∼1580 times) is achieved by tuning the excitation wavelength to be resonant with the microcavity modes. The giant enhancement is attributed to the strong electric field enhancement in the F-P cavity and the oscillator strength enhancement of excitons from suspended WS2. Moreover, directional SH emission (divergence angle ∼5°) is obtained benefiting from the resonance of the F-P microcavity. Our research results can provide a practical sketch to develop both high-efficiency and directional nonlinear optical devices for silicon-based on-chip integration optics.
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Affiliation(s)
- Jianwei Shi
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Xianxin Wu
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Keming Wu
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
| | - Shuai Zhang
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Xinyu Sui
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Wenna Du
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Shuai Yue
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Yin Liang
- School of Materials Science and Engineering, Peking University, Beijing 100871, People's Republic of China
| | - Chuanxiu Jiang
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Zhuo Wang
- SZU-NUS Collaborative Innovation Center for Optoelectronic Science and Technology, 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
| | - Wenxiang Wang
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
| | - Luqi Liu
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
| | - Bo Wu
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology and Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, People's Republic of China
| | - Qing Zhang
- School of Materials Science and Engineering, Peking University, Beijing 100871, People's Republic of China
| | - Yuan Huang
- Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing, 100081, People's Republic of China
| | - Cheng-Wei Qiu
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583, Singapore
| | - Xinfeng Liu
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
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16
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Qian C, Villafañe V, Soubelet P, Hötger A, Taniguchi T, Watanabe K, Wilson NP, Stier AV, Holleitner AW, Finley JJ. Nonlocal Exciton-Photon Interactions in Hybrid High-Q Beam Nanocavities with Encapsulated MoS_{2} Monolayers. PHYSICAL REVIEW LETTERS 2022; 128:237403. [PMID: 35749182 DOI: 10.1103/physrevlett.128.237403] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 02/11/2022] [Accepted: 05/24/2022] [Indexed: 06/15/2023]
Abstract
Atomically thin semiconductors can be readily integrated into a wide range of nanophotonic architectures for applications in quantum photonics and novel optoelectronic devices. We report the observation of nonlocal interactions of "free" trions in pristine hBN/MoS_{2}/hBN heterostructures coupled to single mode (Q>10^{4}) quasi 0D nanocavities. The high excitonic and photonic quality of the interaction system stems from our integrated nanofabrication approach simultaneously with the hBN encapsulation and the maximized local cavity field amplitude within the MoS_{2} monolayer. We observe a nonmonotonic temperature dependence of the cavity-trion interaction strength, consistent with the nonlocal light-matter interactions in which the extent of the center-of-mass (c.m.) wave function is comparable to the cavity mode volume in space. Our approach can be generalized to other optically active 2D materials, opening the way toward harnessing novel light-matter interaction regimes for applications in quantum photonics.
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Affiliation(s)
- Chenjiang Qian
- Walter Schottky Institut and Physik Department, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany
| | - Viviana Villafañe
- Walter Schottky Institut and Physik Department, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany
| | - Pedro Soubelet
- Walter Schottky Institut and Physik Department, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany
| | - Alexander Hötger
- Walter Schottky Institut and Physik Department, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Nathan P Wilson
- Walter Schottky Institut and Physik Department, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany
| | - Andreas V Stier
- Walter Schottky Institut and Physik Department, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany
| | - Alexander W Holleitner
- Walter Schottky Institut and Physik Department, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany
| | - Jonathan J Finley
- Walter Schottky Institut and Physik Department, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany
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17
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Hight-Huf N, Pagaduan JN, Katsumata R, Emrick T, Barnes MD. Stabilization of Three-Particle Excitations in Monolayer MoS 2 by Fluorinated Methacrylate Polymers. J Phys Chem Lett 2022; 13:4794-4799. [PMID: 35613709 DOI: 10.1021/acs.jpclett.2c01150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
While extrinsic factors, such as substrates and chemical doping, are known to strongly influence visible photoemission from monolayer MoS2, key fundamental knowledge for p-type polymeric dopants is lacking. We investigated perturbations to the electronic environment of 2D MoS2 using fluorinated polymer coatings and specifically studied stabilization of three-particle states by monitoring changes in intensities and emission maxima of three-particle and two-particle emissions. We calculated changes in carrier density and trion binding energy, the latter having an additional contribution from MoS2 polarization by the polymer. Polarization is further suggested by Kelvin probe force microscopy (KPFM) measurements of large Fermi level shifts. Changes similar in magnitude, but opposite in sign, were observed in 2D MoS2 coated with an analogous nonfluorinated polymer. These findings highlight the important interplay between electron exchange and electrostatic interactions at the interface between polymers and transition metal dichalcogenides (TMDCs), which govern fundamental electronic properties relevant to next-generation devices.
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18
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Uddin SZ, Higashitarumizu N, Kim H, Yi J, Zhang X, Chrzan D, Javey A. Enhanced Neutral Exciton Diffusion in Monolayer WS 2 by Exciton-Exciton Annihilation. ACS NANO 2022; 16:8005-8011. [PMID: 35467828 DOI: 10.1021/acsnano.2c00956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Dominant recombination pathways in monolayer transition metal dichalcogenides (TMDCs) depend primarily on background carrier concentration, generation rate, and applied strain. Charged excitons formed in the presence of background carriers mainly recombine nonradiatively. Neutral excitons recombine completely radiatively at low generation rates, but experience nonradiative exciton-exciton annihilation (EEA) at high generation rates. Strain can suppress EEA, resulting in near-unity photoluminescence quantum yield (PL QY) at all exciton densities. Although exciton diffusion is the primary channel of energy transport in excitonic materials and a critical optoelectronic design consideration, the combined effects of these factors on exciton diffusion are not clearly understood. In this work, we decouple the diffusion of neutral and charged excitons with chemical counterdoping and explore the effect of strain and generation rate on exciton diffusion. According to the standard semiconductor paradigm, a shorter carrier recombination lifetime should lead to a smaller diffusion length. Surprisingly, we find that increasing generation rate shortens the exciton lifetime but increases the diffusion length in unstrained monolayers of TMDCs. When we suppress EEA by strain, both lifetime and diffusion length become independent of generation rate. During EEA one exciton nonradiatively recombines and kinetically energizes another exciton, which then diffuses fast. Our results probe concentration-dependent diffusion of pure neutral excitons by counterdoping and elucidate how strain controls exciton transport and many-body interactions in TMDC monolayers.
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Affiliation(s)
- Shiekh Zia Uddin
- Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Naoki Higashitarumizu
- Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Hyungjin Kim
- Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Jun Yi
- NSF Nanoscale Science and Engineering Center, University of California, Berkeley, California 94720, United States
| | - Xiang Zhang
- NSF Nanoscale Science and Engineering Center, University of California, Berkeley, California 94720, United States
- Faculties of Sciences and Engineering, The University of Hong Kong, Hong Kong, China
| | - Daryl Chrzan
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Materials Science and Engineering, University of California, Berkeley, Berkeley, California 94720, United States
| | - Ali Javey
- Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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19
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Chou HC, Zhang XQ, Shiau SY, Chien CH, Tang PW, Sung CT, Chang YC, Lee YH, Chen C. Near-field spectroscopic imaging of exciton quenching at atomically sharp MoS 2/WS 2 lateral heterojunctions. NANOSCALE 2022; 14:6323-6330. [PMID: 35297443 DOI: 10.1039/d2nr00216g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Heterojunctions made by laterally stitching two different transition metal dichalcogenide monolayers create a unique one-dimensional boundary with intriguing local optical properties that can only be characterized by nanoscale-spatial-resolution spectral tools. Here, we use near-field photoluminescence (NF-PL) to reveal the narrowest region (105 nm) ever reported of photoluminescence quenching at the junction of a laterally stitched WS2/MoS2 monolayer. We attribute this quenching to the atomically sharp band offset that generates a strong electric force at the junction to easily dissociate excitons. Besides the sharp heterojunction, a model considering various widths of the alloying interfacial region under low or high optical pumping is presented. With a spatial resolution six times better than that of confocal microscopy, NF-PL provides an unprecedented spectral tool for non-scalable 1D lateral heterojunctions.
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Affiliation(s)
- He-Chun Chou
- Research Center for Applied Sciences, Academia Sinica, Taipei, 115, Taiwan.
| | - Xin-Quan Zhang
- Department of Materials Science and Engineering, National Tsing-Hua University, Hsinchu, 300, Taiwan.
| | - Shiue-Yuan Shiau
- Physics Division, National Center for Theoretical Sciences, Taipei, 106, Taiwan
| | - Ching-Hang Chien
- Research Center for Applied Sciences, Academia Sinica, Taipei, 115, Taiwan.
| | - Po-Wen Tang
- Research Center for Applied Sciences, Academia Sinica, Taipei, 115, Taiwan.
| | - Chun-Te Sung
- Research Center for Applied Sciences, Academia Sinica, Taipei, 115, Taiwan.
- Department of Materials Science and Engineering, National Tsing-Hua University, Hsinchu, 300, Taiwan.
| | - Yia-Chung Chang
- Research Center for Applied Sciences, Academia Sinica, Taipei, 115, Taiwan.
| | - Yi-Hsien Lee
- Department of Materials Science and Engineering, National Tsing-Hua University, Hsinchu, 300, Taiwan.
| | - Chi Chen
- Research Center for Applied Sciences, Academia Sinica, Taipei, 115, Taiwan.
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20
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Liu Q, Wei K, Tang Y, Xu Z, Cheng X, Jiang T. Visualizing Hot-Carrier Expansion and Cascaded Transport in WS 2 by Ultrafast Transient Absorption Microscopy. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2105746. [PMID: 35104054 PMCID: PMC8981895 DOI: 10.1002/advs.202105746] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Revised: 01/04/2022] [Indexed: 06/14/2023]
Abstract
The competition between different spatiotemporal carrier relaxation determines the carrier harvesting in optoelectronic semiconductors, which can be greatly optimized by utilizing the ultrafast spatial expansion of highly energetic carriers before their energy dissipation via carrier-phonon interactions. Here, the excited-state dynamics in layered tungsten disulfide (WS2 ) are primarily imaged in the temporal, spatial, and spectral domains by transient absorption microscopy. Ultrafast hot carrier expansion is captured in the first 1.4 ps immediately after photoexcitation, with a mean diffusivity up to 980 cm2 s-1 . This carrier diffusivity then rapidly weakens, reaching a conventional linear spread of 10.5 cm2 s-1 after 2 ps after the hot carriers cool down to the band edge and form bound excitons. The novel carrier diffusion can be well characterized by a cascaded transport model including 3D thermal transport and thermo-optical conversion, in which the carrier temperature gradient and lattice thermal transport govern the initial hot carrier expansion and long-term exciton diffusion rates, respectively. The ultrafast hot carrier expansion breaks the limit of slow exciton diffusion in 2D transition metal dichalcogenides, providing potential guidance for high-performance applications and thermal management of optoelectronic technology.
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Affiliation(s)
- Qirui Liu
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha, 410073, P. R. China
| | - Ke Wei
- State Key Laboratory of High Performance Computing, College of Computer, National University of Defense Technology, Changsha, 410073, P. R. China
- Beijing Institute for Advanced Study, National University of Defense Technology, Beijing, 100000, P. R. China
| | - Yuxiang Tang
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha, 410073, P. R. China
| | - Zhongjie Xu
- 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
- Beijing Institute for Advanced Study, National University of Defense Technology, Beijing, 100000, P. R. China
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21
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Abstract
AbstractExcitons are elementary optical excitation in semiconductors. The ability to manipulate and transport these quasiparticles would enable excitonic circuits and devices for quantum photonic technologies. Recently, interlayer excitons in 2D semiconductors have emerged as a promising candidate for engineering excitonic devices due to their long lifetime, large exciton binding energy, and gate tunability. However, the charge-neutral nature of the excitons leads to weak response to the in-plane electric field and thus inhibits transport beyond the diffusion length. Here, we demonstrate the directional transport of interlayer excitons in bilayer WSe2 driven by the propagating potential traps induced by surface acoustic waves (SAW). We show that at 100 K, the SAW-driven excitonic transport is activated above a threshold acoustic power and reaches 20 μm, a distance at least ten times longer than the diffusion length and only limited by the device size. Temperature-dependent measurement reveals the transition from the diffusion-limited regime at low temperature to the acoustic field-driven regime at elevated temperature. Our work shows that acoustic waves are an effective, contact-free means to control exciton dynamics and transport, promising for realizing 2D materials-based excitonic devices such as exciton transistors, switches, and transducers up to room temperature.
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22
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Lee H, Koo Y, Choi J, Kumar S, Lee HT, Ji G, Choi SH, Kang M, Kim KK, Park HR, Choo H, Park KD. Drift-dominant exciton funneling and trion conversion in 2D semiconductors on the nanogap. SCIENCE ADVANCES 2022; 8:eabm5236. [PMID: 35119920 PMCID: PMC8816338 DOI: 10.1126/sciadv.abm5236] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 12/14/2021] [Indexed: 05/26/2023]
Abstract
Understanding and controlling the nanoscale transport of excitonic quasiparticles in atomically thin two-dimensional (2D) semiconductors are crucial to produce highly efficient nano-excitonic devices. Here, we present a nanogap device to selectively confine excitons or trions of 2D transition metal dichalcogenides at the nanoscale, facilitated by the drift-dominant exciton funneling into the strain-induced local spot. We investigate the spatiospectral characteristics of the funneled excitons in a WSe2 monolayer (ML) and converted trions in a MoS2 ML using hyperspectral tip-enhanced photoluminescence imaging with <15-nm spatial resolution. In addition, we dynamically control the exciton funneling and trion conversion rate by the gigapascal-scale tip pressure engineering. Through a drift-diffusion model, we confirm an exciton funneling efficiency of ∼25% with a significantly low strain threshold (∼0.1%), which sufficiently exceeds the efficiency of ∼3% in previous studies. This work provides a previously unexplored strategy to facilitate efficient exciton transport and trion conversion of 2D semiconductor devices.
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Affiliation(s)
- Hyeongwoo Lee
- Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Yeonjeong Koo
- Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Jinseong Choi
- Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Shailabh Kumar
- Department of Medical Engineering, California Institute of Technology (Caltech), Pasadena, CA 91125, USA
| | - Hyoung-Taek Lee
- Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Gangseon Ji
- Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Soo Ho Choi
- Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
| | - Mingu Kang
- Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Ki Kang Kim
- Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
- Department of Energy Science, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Hyeong-Ryeol Park
- Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Hyuck Choo
- Department of Medical Engineering, California Institute of Technology (Caltech), Pasadena, CA 91125, USA
- Imaging Device Lab, Device and System Research Center, Samsung Advanced Institute of Technology (SAIT), Suwon 16678, Republic of Korea
| | - Kyoung-Duck Park
- Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
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23
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Uddin SZ, Higashitarumizu N, Kim H, Rabani E, Javey A. Engineering Exciton Recombination Pathways in Bilayer WSe 2 for Bright Luminescence. ACS NANO 2022; 16:1339-1345. [PMID: 35014783 DOI: 10.1021/acsnano.1c09255] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Exciton-exciton annihilation (EEA) in counterdoped monolayer transition metal dichalcogenides (TMDCs) can be suppressed by favorably changing the band structure with strain. The photoluminescence (PL) quantum yield (QY) monotonically approaches unity with strain at all generation rates. In contrast, here in bilayers (2L) of tungsten diselenide (WSe2) we observe a nonmonotonic change in EEA rate at high generation rates accompanied by a drastic enhancement in their PL QY at low generation rates. EEA is suppressed at both 0% and 1% strain, but activated at intermediate strains. We explain our observation through the indirect to direct transition in 2L WSe2 under uniaxial tensile strain. By strain and electrostatic counterdoping, we attain ∼50% PL QY at all generation rates in 2L WSe2, originally an indirect semiconductor. We demonstrate transient electroluminescence from 2L WSe2 with ∼1.5% internal quantum efficiency for a broad range of carrier densities by applying strain, which is ∼50 times higher than without strain. The present results elucidate the complete optoelectronic photophysics where indirect and direct excitons are simultaneously present and expedite exciton engineering in a TMDC multilayer beyond indirect-direct bandgap transition.
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Affiliation(s)
- Shiekh Zia Uddin
- Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Naoki Higashitarumizu
- Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Hyungjin Kim
- Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Eran Rabani
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
- The Raymond and Beverly Sackler Center of Computational Molecular and Materials Science, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ali Javey
- Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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24
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Lee Y, Chang S, Chen S, Chen S, Chen H. Optical Inspection of 2D Materials: From Mechanical Exfoliation to Wafer-Scale Growth and Beyond. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2102128. [PMID: 34716758 PMCID: PMC8728831 DOI: 10.1002/advs.202102128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 07/13/2021] [Indexed: 05/11/2023]
Abstract
Optical inspection is a rapid and non-destructive method for characterizing the properties of two-dimensional (2D) materials. With the aid of optical inspection, in situ and scalable monitoring of the properties of 2D materials can be implemented industrially to advance the development and progress of 2D material-based devices toward mass production. This review discusses the optical inspection techniques that are available to characterize various 2D materials, including graphene, transition metal dichalcogenides (TMDCs), hexagonal boron nitride (h-BN), group-III monochalcogenides, black phosphorus (BP), and group-IV monochalcogenides. First, the authors provide an introduction to these 2D materials and the processes commonly used for their fabrication. Then they review several of the important structural properties of 2D materials, and discuss how to characterize them using appropriate optical inspection tools. The authors also describe the challenges and opportunities faced when applying optical inspection to recently developed 2D materials, from mechanically exfoliated to wafer-scale-grown 2D materials. Most importantly, the authors summarize the techniques available for largely and precisely enhancing the optical signals from 2D materials. This comprehensive review of the current status and perspective of future trends for optical inspection of the structural properties of 2D materials will facilitate the development of next-generation 2D material-based devices.
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Affiliation(s)
- Yang‐Chun Lee
- Department of Materials Science and EngineeringNational Taiwan UniversityNo. 1, Sec. 4, Roosevelt RoadTaipei10617Taiwan
| | - Sih‐Wei Chang
- Department of Materials Science and EngineeringNational Taiwan UniversityNo. 1, Sec. 4, Roosevelt RoadTaipei10617Taiwan
| | - Shu‐Hsien Chen
- Department of Materials Science and EngineeringNational Taiwan UniversityNo. 1, Sec. 4, Roosevelt RoadTaipei10617Taiwan
| | - Shau‐Liang Chen
- Department of Materials Science and EngineeringNational Taiwan UniversityNo. 1, Sec. 4, Roosevelt RoadTaipei10617Taiwan
| | - Hsuen‐Li Chen
- Department of Materials Science and EngineeringNational Taiwan UniversityNo. 1, Sec. 4, Roosevelt RoadTaipei10617Taiwan
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25
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Rosati R, Wagner K, Brem S, Perea-Causín R, Ziegler JD, Zipfel J, Taniguchi T, Watanabe K, Chernikov A, Malic E. Non-equilibrium diffusion of dark excitons in atomically thin semiconductors. NANOSCALE 2021; 13:19966-19972. [PMID: 34821228 DOI: 10.1039/d1nr06230a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Atomically thin semiconductors provide an excellent platform to study intriguing many-particle physics of tightly-bound excitons. In particular, the properties of tungsten-based transition metal dichalcogenides are determined by a complex manifold of bright and dark exciton states. While dark excitons are known to dominate the relaxation dynamics and low-temperature photoluminescence, their impact on the spatial propagation of excitons has remained elusive. In our joint theory-experiment study, we address this intriguing regime of dark state transport by resolving the spatio-temporal exciton dynamics in hBN-encapsulated WSe2 monolayers after resonant excitation. We find clear evidence of an unconventional, time-dependent diffusion during the first tens of picoseconds, exhibiting strong deviation from the steady-state propagation. Dark exciton states are initially populated by phonon emission from the bright states, resulting in creation of hot (unequilibrated) excitons whose rapid expansion leads to a transient increase of the diffusion coefficient by more than one order of magnitude. These findings are relevant for both fundamental understanding of the spatio-temporal exciton dynamics in atomically thin materials as well as their technological application by enabling rapid diffusion.
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Affiliation(s)
- Roberto Rosati
- Department of Physics, Philipps-Universität Marburg, Renthof 7, D-35032 Marburg, Germany.
| | - Koloman Wagner
- Department of Physics, University of Regensburg, Regensburg D-93053, Germany
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany
| | - Samuel Brem
- Department of Physics, Philipps-Universität Marburg, Renthof 7, D-35032 Marburg, Germany.
| | - Raül Perea-Causín
- Chalmers University of Technology, Department of Physics, 412 96 Gothenburg, Sweden
| | - Jonas D Ziegler
- Department of Physics, University of Regensburg, Regensburg D-93053, Germany
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany
| | - Jonas Zipfel
- Department of Physics, University of Regensburg, Regensburg D-93053, Germany
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Ibaraki 305-004, Japan
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Ibaraki 305-004, Japan
| | - Alexey Chernikov
- Department of Physics, University of Regensburg, Regensburg D-93053, Germany
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany
| | - Ermin Malic
- Department of Physics, Philipps-Universität Marburg, Renthof 7, D-35032 Marburg, Germany.
- Chalmers University of Technology, Department of Physics, 412 96 Gothenburg, Sweden
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26
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Chen P, Atallah TL, Lin Z, Wang P, Lee SJ, Xu J, Huang Z, Duan X, Ping Y, Huang Y, Caram JR, Duan X. Approaching the intrinsic exciton physics limit in two-dimensional semiconductor diodes. Nature 2021; 599:404-410. [PMID: 34789906 DOI: 10.1038/s41586-021-03949-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 08/24/2021] [Indexed: 11/09/2022]
Abstract
Two-dimensional (2D) semiconductors have attracted intense interest for their unique photophysical properties, including large exciton binding energies and strong gate tunability, which arise from their reduced dimensionality1-5. Despite considerable efforts, a disconnect persists between the fundamental photophysics in pristine 2D semiconductors and the practical device performances, which are often plagued by many extrinsic factors, including chemical disorder at the semiconductor-contact interface. Here, by using van der Waals contacts with minimal interfacial disorder, we suppress contact-induced Shockley-Read-Hall recombination and realize nearly intrinsic photophysics-dictated device performance in 2D semiconductor diodes. Using an electrostatic field in a split-gate geometry to independently modulate electron and hole doping in tungsten diselenide diodes, we discover an unusual peak in the short-circuit photocurrent at low charge densities. Time-resolved photoluminescence reveals a substantial decrease of the exciton lifetime from around 800 picoseconds in the charge-neutral regime to around 50 picoseconds at high doping densities owing to increased exciton-charge Auger recombination. Taken together, we show that an exciton-diffusion-limited model well explains the charge-density-dependent short-circuit photocurrent, a result further confirmed by scanning photocurrent microscopy. We thus demonstrate the fundamental role of exciton diffusion and two-body exciton-charge Auger recombination in 2D devices and highlight that the intrinsic photophysics of 2D semiconductors can be used to create more efficient optoelectronic devices.
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Affiliation(s)
- Peng Chen
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA
| | - Timothy L Atallah
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA
| | - Zhaoyang Lin
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA
| | - Peiqi Wang
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA
| | - Sung-Joon Lee
- Department of Materials Science and Engineering, University of California, Los Angeles, Los Angeles, CA, USA
| | - Junqing Xu
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Zhihong Huang
- Department of Materials Science and Engineering, University of California, Los Angeles, Los Angeles, CA, USA
| | - Xidong Duan
- State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, China
| | - Yuan Ping
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Yu Huang
- Department of Materials Science and Engineering, University of California, Los Angeles, Los Angeles, CA, USA.,California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, USA
| | - Justin R Caram
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA. .,California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, USA.
| | - Xiangfeng Duan
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA. .,California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, USA.
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27
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Wagner K, Zipfel J, Rosati R, Wietek E, Ziegler JD, Brem S, Perea-Causín R, Taniguchi T, Watanabe K, Glazov MM, Malic E, Chernikov A. Nonclassical Exciton Diffusion in Monolayer WSe_{2}. PHYSICAL REVIEW LETTERS 2021; 127:076801. [PMID: 34459627 DOI: 10.1103/physrevlett.127.076801] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 06/24/2021] [Indexed: 06/13/2023]
Abstract
We experimentally demonstrate time-resolved exciton propagation in a monolayer semiconductor at cryogenic temperatures. Monitoring phonon-assisted recombination of dark states, we find a highly unusual case of exciton diffusion. While at 5 K the diffusivity is intrinsically limited by acoustic phonon scattering, we observe a pronounced decrease of the diffusion coefficient with increasing temperature, far below the activation threshold of higher-energy phonon modes. This behavior corresponds neither to well-known regimes of semiclassical free-particle transport nor to the thermally activated hopping in systems with strong localization. Its origin is discussed in the framework of both microscopic numerical and semiphenomenological analytical models illustrating the observed characteristics of nonclassical propagation. Challenging the established description of mobile excitons in monolayer semiconductors, these results open up avenues to study quantum transport phenomena for excitonic quasiparticles in atomically thin van der Waals materials and their heterostructures.
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Affiliation(s)
- Koloman Wagner
- Department of Physics, University of Regensburg, Regensburg D-93053, Germany
| | - Jonas Zipfel
- Department of Physics, University of Regensburg, Regensburg D-93053, Germany
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Roberto Rosati
- Department of Physics, Philipps-Universität Marburg, Renthof 7, Marburg D-35032, Germany
| | - Edith Wietek
- Department of Physics, University of Regensburg, Regensburg D-93053, Germany
| | - Jonas D Ziegler
- Department of Physics, University of Regensburg, Regensburg D-93053, Germany
| | - Samuel Brem
- Department of Physics, Philipps-Universität Marburg, Renthof 7, Marburg D-35032, Germany
| | - Raül Perea-Causín
- Department of Physics, Chalmers University of Technology, Fysikgården 1, 41258 Gothenburg, Sweden
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Ibaraki 305-004, Japan
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Ibaraki 305-004, Japan
| | | | - Ermin Malic
- Department of Physics, Philipps-Universität Marburg, Renthof 7, Marburg D-35032, Germany
- Department of Physics, Chalmers University of Technology, Fysikgården 1, 41258 Gothenburg, Sweden
| | - Alexey Chernikov
- Department of Physics, University of Regensburg, Regensburg D-93053, Germany
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany
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28
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Cheng G, Li B, Jin Z, Zhang M, Wang J. Observation of Diffusion and Drift of the Negative Trions in Monolayer WS 2. NANO LETTERS 2021; 21:6314-6320. [PMID: 34250802 DOI: 10.1021/acs.nanolett.1c02351] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Monolayer transition metal dichalcogenides (ML-TMDCs) are a versatile platform to explore the transport dynamics of the tightly bound excitonic states. The diffusion of neutral excitons in various ML-TMDCs has been observed. However, the transport of charged excitons (trions), which can be driven by an in-plane electric field and facilitate the formation of an excitonic current, has yet been well investigated. Here, we report the direct observation of diffusion and drift of the trions in ML-WS2 through spatially and time-resolved photoluminescence. An effective diffusion coefficient of 0.47 cm2/s was extracted from the broadening of spatial profiles of the trion emission. When an in-plane electric field is applied, the spatial shift of the trion emission profiles indicated a drift velocity of 7400 cm/s. Both the diffusion caused broadening and the drift caused shift of the emission profiles saturate because of the Coulomb interactions between trions and the background charges.
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Affiliation(s)
- Guanghui Cheng
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
- Department of Physics and Astronomy, Purdue Quantum Science and Engineering Institute, Purdue University, West Lafayette, Indiana 47907, United States
- WPI Advanced Institute for Materials Research (AIMR), Tohoku University, Sendai 980-8577, Japan
| | - Baikui Li
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, Guangdong 518060, China
| | - Zijing Jin
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Meng Zhang
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, Guangdong 518060, China
| | - Jiannong Wang
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
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