1
|
Lin Q, Fang H, Kalaboukhov A, Liu Y, Zhang Y, Fischer M, Li J, Hagel J, Brem S, Malic E, Stenger N, Sun Z, Wubs M, Xiao S. Moiré-engineered light-matter interactions in MoS 2/WSe 2 heterobilayers at room temperature. Nat Commun 2024; 15:8762. [PMID: 39384821 PMCID: PMC11464769 DOI: 10.1038/s41467-024-53083-x] [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: 04/10/2024] [Accepted: 09/26/2024] [Indexed: 10/11/2024] Open
Abstract
Moiré superlattices in van der Waals heterostructures represent a highly tunable quantum system, attracting substantial interest in both many-body physics and device applications. However, the influence of the moiré potential on light-matter interactions at room temperature has remained largely unexplored. In our study, we demonstrate that the moiré potential in MoS2/WSe2 heterobilayers facilitates the localization of interlayer exciton (IX) at room temperature. By performing reflection contrast spectroscopy, we demonstrate the importance of atomic reconstruction in modifying intralayer excitons, supported by the atomic force microscopy experiment. When decreasing the twist angle, we observe that the IX lifetime becomes longer and light emission gets enhanced, indicating that non-radiative decay channels such as defects are suppressed by the moiré potential. Moreover, through the integration of moiré superlattices with silicon single-mode cavities, we find that the devices employing moiré-trapped IXs exhibit a significantly lower threshold, one order of magnitude smaller compared to the device utilizing delocalized IXs. These findings not only encourage the exploration of many-body physics in moiré superlattices at elevated temperatures but also pave the way for leveraging these artificial quantum materials in photonic and optoelectronic applications.
Collapse
Affiliation(s)
- Qiaoling Lin
- Department of Electrical and Photonics Engineering, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark
- NanoPhoton - Center for Nanophotonics, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark
- Centre for Nanostructured Graphene, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark
| | - Hanlin Fang
- Department of Electrical and Photonics Engineering, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark.
- NanoPhoton - Center for Nanophotonics, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark.
- Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, 41296, Gothenburg, Sweden.
| | - Alexei Kalaboukhov
- Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, 41296, Gothenburg, Sweden
| | - Yuanda Liu
- Institute of Materials Research and Engineering, Agency for Science Technology and Research (A*STAR), 2 Fusionopolis Way, 138634, Singapore, Singapore
| | - Yi Zhang
- Department of Electronics and Nanoengineering and QTF Centre of Excellence, Aalto University, Espoo, 02150, Finland
| | - Moritz Fischer
- Department of Electrical and Photonics Engineering, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark
- NanoPhoton - Center for Nanophotonics, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark
- Centre for Nanostructured Graphene, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark
| | - Juntao Li
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-Sen University, Guangzhou, 510275, China
| | - Joakim Hagel
- Department of Physics, Chalmers University of Technology, 41296, Gothenburg, Sweden
| | - Samuel Brem
- Department of Physics, Philipps-Universität Marburg, 35037, Marburg, Germany
| | - Ermin Malic
- Department of Physics, Philipps-Universität Marburg, 35037, Marburg, Germany
| | - Nicolas Stenger
- Department of Electrical and Photonics Engineering, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark
- NanoPhoton - Center for Nanophotonics, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark
- Centre for Nanostructured Graphene, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark
| | - Zhipei Sun
- Department of Electronics and Nanoengineering and QTF Centre of Excellence, Aalto University, Espoo, 02150, Finland
| | - Martijn Wubs
- Department of Electrical and Photonics Engineering, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark
- NanoPhoton - Center for Nanophotonics, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark
- Centre for Nanostructured Graphene, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark
| | - Sanshui Xiao
- Department of Electrical and Photonics Engineering, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark.
- NanoPhoton - Center for Nanophotonics, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark.
- Centre for Nanostructured Graphene, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark.
| |
Collapse
|
2
|
Xie M, Hafezi M, Das Sarma S. Long-Lived Topological Flatband Excitons in Semiconductor Moiré Heterostructures: A Bosonic Kane-Mele Model Platform. PHYSICAL REVIEW LETTERS 2024; 133:136403. [PMID: 39392947 DOI: 10.1103/physrevlett.133.136403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Revised: 07/31/2024] [Accepted: 08/24/2024] [Indexed: 10/13/2024]
Abstract
Moiré superlattices based on two-dimensional transition metal dichalcogenides (TMDs) have emerged as a highly versatile and fruitful platform for exploring correlated topological electronic phases. One of the most remarkable examples is the recently discovered fractional quantum anomalous Hall effect (FQAHE) under zero magnetic field. Here, we propose a minimal structure that hosts long-lived excitons-a ubiquitous bosonic excitation in TMD semiconductors-with narrow topological bosonic bands. The nontrivial exciton topology originates from hybridization of moiré interlayer excitons and is tunable by controlling twist angle and electric field. At small twist angle, the lowest exciton bands are isolated from higher energy bands and provide a solid-state realization of the bosonic Kane-Mele model with topological flatbands, which could potentially support the bosonic version of FQAHE.
Collapse
Affiliation(s)
| | | | - Sankar Das Sarma
- Condensed Matter Theory Center, Department of Physics, University of Maryland, College Park, Maryland 20742, USA
- Joint Quantum Institute, Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| |
Collapse
|
3
|
Alexeev EM, Purser CM, Gilardoni CM, Kerfoot J, Chen H, Cadore AR, Rosa BLT, Feuer MSG, Javary E, Hays P, Watanabe K, Taniguchi T, Tongay SA, Kara DM, Atatüre M, Ferrari AC. Nature of Long-Lived Moiré Interlayer Excitons in Electrically Tunable MoS 2/MoSe 2 Heterobilayers. NANO LETTERS 2024; 24:11232-11238. [PMID: 39213644 PMCID: PMC11403766 DOI: 10.1021/acs.nanolett.4c02635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Interlayer excitons in transition-metal dichalcogenide heterobilayers combine high binding energy and valley-contrasting physics with a long optical lifetime and strong dipolar character. Their permanent electric dipole enables electric-field control of the emission energy, lifetime, and location. Device material and geometry impact the nature of the interlayer excitons via their real- and momentum-space configurations. Here, we show that interlayer excitons in MoS2/MoSe2 heterobilayers are formed by charge carriers residing at the Brillouin zone edges, with negligible interlayer hybridization. We find that the moiré superlattice leads to the reversal of the valley-dependent optical selection rules, yielding a positively valued g-factor and cross-polarized photoluminescence. Time-resolved photoluminescence measurements reveal that the interlayer exciton population retains the optically induced valley polarization throughout its microsecond-long lifetime. The combination of a long optical lifetime and valley polarization retention makes MoS2/MoSe2 heterobilayers a promising platform for studying fundamental bosonic interactions and developing excitonic circuits for optical information processing.
Collapse
Affiliation(s)
- Evgeny M Alexeev
- Cambridge Graphene Centre, University of Cambridge, 9 JJ Thomson Avenue, CB3 0FA Cambridge, U.K
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, U.K
| | - Carola M Purser
- Cambridge Graphene Centre, University of Cambridge, 9 JJ Thomson Avenue, CB3 0FA Cambridge, U.K
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, U.K
| | - Carmem M Gilardoni
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, U.K
| | - James Kerfoot
- Cambridge Graphene Centre, University of Cambridge, 9 JJ Thomson Avenue, CB3 0FA Cambridge, U.K
| | - Hao Chen
- Cambridge Graphene Centre, University of Cambridge, 9 JJ Thomson Avenue, CB3 0FA Cambridge, U.K
| | - Alisson R Cadore
- Cambridge Graphene Centre, University of Cambridge, 9 JJ Thomson Avenue, CB3 0FA Cambridge, U.K
- Brazilian Nanotechnology National Laboratory (LNNano), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, 13083-849 Sao Paulo, Brazil
| | - Bárbara L T Rosa
- Cambridge Graphene Centre, University of Cambridge, 9 JJ Thomson Avenue, CB3 0FA Cambridge, U.K
| | - Matthew S G Feuer
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, U.K
| | - Evans Javary
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, U.K
- École Normale Supérieure, PSL, 5 Rue D'ulm, Paris 75005, France
| | - Patrick Hays
- Materials Science and Engineering, School for Engineering of Matter,Transport and Energy, Arizona State University, Tempe, Arizona 85287, United States
| | - Kenji Watanabe
- Research Center for Electronic and Optical Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Seth Ariel Tongay
- Materials Science and Engineering, School for Engineering of Matter,Transport and Energy, Arizona State University, Tempe, Arizona 85287, United States
| | - Dhiren M Kara
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, U.K
| | - Mete Atatüre
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, U.K
| | - Andrea C Ferrari
- Cambridge Graphene Centre, University of Cambridge, 9 JJ Thomson Avenue, CB3 0FA Cambridge, U.K
| |
Collapse
|
4
|
de la Torre A, Kennes DM, Malic E, Kar S. Advanced Characterization of the Spatial Variation of Moiré Heterostructures and Moiré Excitons. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2401474. [PMID: 39248703 DOI: 10.1002/smll.202401474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2024] [Revised: 07/24/2024] [Indexed: 09/10/2024]
Abstract
In this short review, an overview of recent progress in deploying advanced characterization techniques is provided to understand the effects of spatial variation and inhomogeneities in moiré heterostructures over multiple length scales. Particular emphasis is placed on correlating the impact of twist angle misalignment, nano-scale disorder, and atomic relaxation on the moiré potential and its collective excitations, particularly moiré excitons. Finally, future technological applications leveraging moiré excitons are discussed.
Collapse
Affiliation(s)
- Alberto de la Torre
- Department of Physics, Northeastern University, Boston, MA, 02115, USA
- Quantum Materials and Sensing Institute, Northeastern University, Burlington, MA, 01803, USA
| | - Dante M Kennes
- Institute for Theory of Statistical Physics, RWTH Aachen University, and JARA Fundamentals of Future Information Technology, 52062, Aachen, Germany
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science, 22761, Hamburg, Germany
| | - Ermin Malic
- Fachbereich Physik, Philipps-Universität Marburg, 35032, Marburg, Germany
- Department of Physics, Chalmers University of Technology, Gothenburg, 41296, Sweden
| | - Swastik Kar
- Department of Physics, Northeastern University, Boston, MA, 02115, USA
- Quantum Materials and Sensing Institute, Northeastern University, Burlington, MA, 01803, USA
- Department of Chemical Engineering, Northeastern University, Boston, MA, 02115, USA
| |
Collapse
|
5
|
Brotons-Gisbert M, Gerardot BD, Holleitner AW, Wurstbauer U. Interlayer and Moiré excitons in atomically thin double layers: From individual quantum emitters to degenerate ensembles. MRS BULLETIN 2024; 49:914-931. [PMID: 39247683 PMCID: PMC11379794 DOI: 10.1557/s43577-024-00772-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 07/13/2024] [Indexed: 09/10/2024]
Abstract
Abstract Interlayer excitons (IXs), composed of electron and hole states localized in different layers, excel in bilayers composed of atomically thin van der Waals materials such as semiconducting transition-metal dichalcogenides (TMDs) due to drastically enlarged exciton binding energies, exciting spin-valley properties, elongated lifetimes, and large permanent dipoles. The latter allows modification by electric fields and the study of thermalized bosonic quasiparticles, from the single particle level to interacting degenerate dense ensembles. Additionally, the freedom to combine bilayers of different van der Waals materials without lattice or relative twist-angle constraints leads to layer-hybridized and Moiré excitons, which can be widely engineered. This article covers fundamental aspects of IXs, including correlation phenomena as well as the consequence of Moiré superlattices with a strong focus on TMD homo- and heterobilayers. Graphical abstract
Collapse
Affiliation(s)
- Mauro Brotons-Gisbert
- Institute of Photonics and Quantum Sciences, SUPA, Heriot-Watt University, Edinburgh, UK
| | - Brian D Gerardot
- Institute of Photonics and Quantum Sciences, SUPA, Heriot-Watt University, Edinburgh, UK
| | - Alexander W Holleitner
- Walter Schottky Institute and Physics Department, Technical University of Munich, Garching, Germany
| | | |
Collapse
|
6
|
Kumar AM, Yagodkin D, Rosati R, Bock DJ, Schattauer C, Tobisch S, Hagel J, Höfer B, Kirchhof JN, Hernández López P, Burfeindt K, Heeg S, Gahl C, Libisch F, Malic E, Bolotin KI. Strain fingerprinting of exciton valley character in 2D semiconductors. Nat Commun 2024; 15:7546. [PMID: 39214968 PMCID: PMC11364664 DOI: 10.1038/s41467-024-51195-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Accepted: 07/30/2024] [Indexed: 09/04/2024] Open
Abstract
Intervalley excitons with electron and hole wavefunctions residing in different valleys determine the long-range transport and dynamics observed in many semiconductors. However, these excitons with vanishing oscillator strength do not directly couple to light and, hence, remain largely unstudied. Here, we develop a simple nanomechanical technique to control the energy hierarchy of valleys via their contrasting response to mechanical strain. We use our technique to discover previously inaccessible intervalley excitons associated with K, Γ, or Q valleys in prototypical 2D semiconductors WSe2 and WS2. We also demonstrate a new brightening mechanism, rendering an otherwise "dark" intervalley exciton visible via strain-controlled hybridization with an intravalley exciton. Moreover, we classify various localized excitons from their distinct strain response and achieve large tuning of their energy. Overall, our valley engineering approach establishes a new way to identify intervalley excitons and control their interactions in a diverse class of 2D systems.
Collapse
Affiliation(s)
- Abhijeet M Kumar
- Department of Physics, Freie Universität Berlin, Arnimallee 14, Berlin, Germany
| | - Denis Yagodkin
- Department of Physics, Freie Universität Berlin, Arnimallee 14, Berlin, Germany
| | - Roberto Rosati
- Philipps-Universität Marburg, Mainzer Gasse 33, Marburg, Germany
| | - Douglas J Bock
- Department of Physics, Freie Universität Berlin, Arnimallee 14, Berlin, Germany
| | - Christoph Schattauer
- Institute for Theoretical Physics, TU Wien, Wiedner Hauptstraße 8-10, Vienna, Austria
| | - Sarah Tobisch
- Institute for Theoretical Physics, TU Wien, Wiedner Hauptstraße 8-10, Vienna, Austria
| | - Joakim Hagel
- Department of Physics, Chalmers University of Technology, 412 96 Gothenburg, Gothenburg, Sweden
| | - Bianca Höfer
- Department of Physics, Freie Universität Berlin, Arnimallee 14, Berlin, Germany
| | - Jan N Kirchhof
- Department of Physics, Freie Universität Berlin, Arnimallee 14, Berlin, Germany
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, Delft, The Netherlands
| | - Pablo Hernández López
- Institute for Physics and IRIS Adlershof, Humboldt-Universität Berlin, Newtonstraße 15, Berlin, Germany
| | - Kenneth Burfeindt
- Department of Physics, Freie Universität Berlin, Arnimallee 14, Berlin, Germany
| | - Sebastian Heeg
- Institute for Physics and IRIS Adlershof, Humboldt-Universität Berlin, Newtonstraße 15, Berlin, Germany
| | - Cornelius Gahl
- Department of Physics, Freie Universität Berlin, Arnimallee 14, Berlin, Germany
| | - Florian Libisch
- Institute for Theoretical Physics, TU Wien, Wiedner Hauptstraße 8-10, Vienna, Austria
| | - Ermin Malic
- Philipps-Universität Marburg, Mainzer Gasse 33, Marburg, Germany
| | - Kirill I Bolotin
- Department of Physics, Freie Universität Berlin, Arnimallee 14, Berlin, Germany.
| |
Collapse
|
7
|
Borghi MTA, Wilson NR. Cathodoluminescence from interlayer excitons in a 2D semiconductor heterobilayer. NANOTECHNOLOGY 2024; 35:465203. [PMID: 39158548 DOI: 10.1088/1361-6528/ad70b3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2024] [Accepted: 08/14/2024] [Indexed: 08/20/2024]
Abstract
Photoluminescence has widely been used to study excitons in semiconducting transition metal dichalcogenide (MX2) monolayers, demonstrating strong light-matter interactions and locked spin and valley degrees of freedom. In heterobilayers composed of overlapping monolayers of two different MX2, an interlayer exciton can form, with the hole localised in one layer and the electron in the other. These interlayer excitons are long-lived, field-tunable, and can be trapped by moiré patterns formed at small twist angles between the layers. Here we demonstrate that emission from radiative recombination of interlayer excitons can be observed by cathodoluminescence from a WSe2/MoSe2heterobilayer encapsulated in hexagonal boron nitride. The higher spatial resolution of cathodoluminescence, compared to photoluminescence, allows detailed analysis of sample heterogeneity at the 100 s of nm lengthscales over which twist angles tend to vary in dry-transfer fabricated heterostructures.
Collapse
Affiliation(s)
- Matteo T A Borghi
- Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Neil R Wilson
- Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
| |
Collapse
|
8
|
Zerba C, Kuhlenkamp C, Imamoğlu A, Knap M. Realizing Topological Superconductivity in Tunable Bose-Fermi Mixtures with Transition Metal Dichalcogenide Heterostructures. PHYSICAL REVIEW LETTERS 2024; 133:056902. [PMID: 39159121 DOI: 10.1103/physrevlett.133.056902] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 06/21/2024] [Indexed: 08/21/2024]
Abstract
Heterostructures of two-dimensional transition metal dichalcogenides are emerging as a promising platform for investigating exotic correlated states of matter. Here, we propose to engineer Bose-Fermi mixtures in these systems by coupling interlayer excitons to doped charges in a trilayer structure. Their interactions are determined by the interlayer trion, whose spin-selective nature allows excitons to mediate an attractive interaction between charge carriers of only one spin species. Remarkably, we find that this causes the system to become unstable to topological p+ip superconductivity at low temperatures. We then demonstrate a general mechanism to develop and control this unconventional state by tuning the trion binding energy using a solid-state Feshbach resonance.
Collapse
Affiliation(s)
| | - Clemens Kuhlenkamp
- Technical University of Munich, TUM School of Natural Sciences, Physics Department, 85748 Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), Schellingstrasse 4, 80799 München, Germany
- Institute for Quantum Electronics, ETH Zürich, CH-8093 Zürich, Switzerland
| | | | | |
Collapse
|
9
|
Biswas A, Rowberg AJE, Yadav P, Moon K, Blanchard GJ, Kweon KE, Kim S. Ag Intercalation in Layered Cs 3Bi 2Br 9 Perovskite for Enhanced Light Emission with Bound Interlayer Excitons. J Am Chem Soc 2024; 146:19919-19928. [PMID: 38982766 PMCID: PMC11273344 DOI: 10.1021/jacs.4c03191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 06/24/2024] [Accepted: 06/25/2024] [Indexed: 07/11/2024]
Abstract
Cesium bismuth bromide (CBB) has garnered considerable attention as a vacancy-ordered layered perovskite with notable optoelectronic applications. However, its use as a light source has been limited due to its weak photoluminescence (PL). Here, we demonstrate metal intercalation as a novel approach to engineer the room-temperature PL of CBB using experimental and computational methods. Ag, when introduced into CBB, occupies vacant sites in the spacer region, forming octahedral coordination with surrounding Br anions. First-principles density functional theory calculations reveal that intercalated Ag represents the most energetically stable Ag species compared to other potential forms, such as Ag substituting Bi. The intercalated Ag forms a strong polaronic trap state close to the conduction band minimum and quickly captures photoexcited electrons with holes remaining in CBB layers, leading to the formation of a bound interlayer exciton, or BIE. The radiative recombination of this BIE exhibits bright room-temperature PL at 600 nm and a decay time of 38.6 ns, 35 times greater than that of free excitons, originating from the spatial separation of photocarriers by half a unit cell separation distance. The BIE as a new form of interlayer exciton is expected to inspire new research directions for vacancy-ordered perovskites.
Collapse
Affiliation(s)
- Anupam Biswas
- Department
of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Andrew J. E. Rowberg
- Quantum
Simulations Group and Laboratory for Energy Applications for the Future
(LEAF), Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Pushpender Yadav
- Department
of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Kyeongdeuk Moon
- Department
of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Gary J. Blanchard
- Department
of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Kyoung E. Kweon
- Quantum
Simulations Group and Laboratory for Energy Applications for the Future
(LEAF), Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Seokhyoung Kim
- Department
of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| |
Collapse
|
10
|
Wu K, Yang Z, Shi Y, Wang Y, Xiang B, Zhou H, Chen W, Zhang S, Xu H, Xiong Q. Revealing the Optical Transition Properties of Interlayer Excitons in Defective WS 2/WSe 2 Heterobilayers. NANO LETTERS 2024; 24:8671-8678. [PMID: 38975929 DOI: 10.1021/acs.nanolett.4c02025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/09/2024]
Abstract
Manipulation of physical properties in multidimensional tunable moiré superlattice systems is a key focus in nanophotonics, especially for interlayer excitons (IXs) in two-dimensional materials. However, the impact of defects on IXs remains unclear. Here, we thoroughly study the optical properties of WS2/WSe2 heterobilayers with varying defect densities. Low-temperature photoluminescence (PL) characterizations reveal that the low-energy IXs are more susceptible to defects compared to the high-energy IXs. The low-energy IXs also show much faster PL quenching rate with temperature, faster peak width broadening rate with laser power, shorter lifetime, and lower circular polarization compared to the low-energy IXs in the region with fewer defects. These effects are attributed to the combined effects of increased electron scattering, exciton-phonon interactions, and nonradiative channels introduced by the defects. Our findings aid in optimizing moiré superlattice structures.
Collapse
Affiliation(s)
- Ke Wu
- School of Sciences, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Ziyi Yang
- School of Sciences, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Yanwei Shi
- School of Sciences, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Yubin Wang
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China
| | - Baixu Xiang
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China
| | - Hongzhi Zhou
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou 311200, Zhejiang, China
| | - Wen Chen
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, China
| | - Shunping Zhang
- School of Physics and Technology and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Wuhan University, Wuhan 430072, China
- Wuhan Institute of Quantum Technology, Wuhan 430206, China
| | - Hongxing Xu
- School of Physics and Technology and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Wuhan University, Wuhan 430072, China
- Institute of Quantum Materials and Physics, Henan Academy of Sciences, Zhengzhou 450046, China
| | - Qihua Xiong
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China
| |
Collapse
|
11
|
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.
Collapse
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
| |
Collapse
|
12
|
Zhang D, Ge C, Wang Y, Xia Y, Zhao H, Yao C, Chen Y, Ma C, Tong Q, Pan A, Wang X. Enhancing Layer-Engineered Interlayer Exciton Emission and Valley Polarization in van der Waals Heterostructures via Strain. ACS NANO 2024; 18:17672-17680. [PMID: 38920321 DOI: 10.1021/acsnano.4c02377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/27/2024]
Abstract
Layer-engineered interlayer excitons from heterostructures of transition-metal dichalcogenides (TMDCs) exhibit a rich variety of emissive states and intriguing valley spin-selection rules, the effective modulation of which is crucial for excitonic physics and related device applications. Strain or high pressure provides the possibility to tune the energy of the interlayer excitons; however, the reported emission intensity is substantially quenched, which greatly limits their practical application in optoelectronic devices. Here, via applying uniaxial strain based on polyvinyl alcohol (PVA) encapsulation technique, we report enhanced layer-engineered interlayer exciton emission intensity with largely modulated emission energy in WSe2/WS2 heterobilayer and heterotrilayer. Both momentum-direct and momentum-indirect interlayer excitons were observed, and their emission energies show an opposite shift tendency upon applied strain, which agrees with our DFT calculations. We further demonstrate that intralayer and interlayer exciton states with low phonon interactions can be modulated through the mechanical strain applied to the PVA substrate at low temperatures. Due to strain-induced breaking of the 3-fold rotational symmetry, we observe the enhanced valley polarization of interlayer excitons. Our study contributes to the understanding and modulation of the optical properties of interlayer excitons, which could be exploited for optoelectronic device applications.
Collapse
Affiliation(s)
- Danliang Zhang
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, School of Physics and Electronics, College of Materials Science and Engineering, Hunan University, Changsha 410082, China
| | - Cuihuang Ge
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, School of Physics and Electronics, College of Materials Science and Engineering, Hunan University, Changsha 410082, China
| | - Youwen Wang
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, School of Physics and Electronics, College of Materials Science and Engineering, Hunan University, Changsha 410082, China
| | - Yang Xia
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, School of Physics and Electronics, College of Materials Science and Engineering, Hunan University, Changsha 410082, China
| | - Haipeng Zhao
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, School of Physics and Electronics, College of Materials Science and Engineering, Hunan University, Changsha 410082, China
| | - Chengdong Yao
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, School of Physics and Electronics, College of Materials Science and Engineering, Hunan University, Changsha 410082, China
| | - Ying Chen
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, School of Physics and Electronics, College of Materials Science and Engineering, Hunan University, Changsha 410082, China
| | - Chao Ma
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, School of Physics and Electronics, College of Materials Science and Engineering, Hunan University, Changsha 410082, China
| | - Qingjun Tong
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, School of Physics and Electronics, College of Materials Science and Engineering, Hunan University, Changsha 410082, China
| | - Anlian Pan
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, School of Physics and Electronics, College of Materials Science and Engineering, Hunan University, Changsha 410082, China
| | - Xiao Wang
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, School of Physics and Electronics, College of Materials Science and Engineering, Hunan University, Changsha 410082, China
| |
Collapse
|
13
|
Ou Z, Wang C, Tao ZG, Li Y, Li Z, Zeng Y, Li Y, Shi E, Chu W, Wang T, Xu H. Organic Ligand Engineering for Tailoring Electron-Phonon Coupling in 2D Hybrid Perovskites. NANO LETTERS 2024; 24:5975-5983. [PMID: 38726841 DOI: 10.1021/acs.nanolett.4c00463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2024]
Abstract
In the emerging two-dimensional organic-inorganic hybrid perovskites, the electronic structures and carrier behaviors are strongly impacted by intrinsic electron-phonon interactions, which have received inadequate attention. In this study, we report an intriguing phenomenon of negative carrier diffusion induced by electron-phonon coupling in (2T)2PbI4. Theoretical calculations reveal that the electron-phonon coupling drives the band alignment in (2T)2PbI4 to alternate between type I and type II heterostructures. As a consequence, photoexcited holes undergo transitions between the organic ligands and inorganic layers, resulting in abnormal carrier transport behavior compared to other two-dimensional hybrid perovskites. These findings provide valuable insights into the role of electron-phonon coupling in shaping the band alignments and carrier behaviors in two-dimensional hybrid perovskites. They also open up exciting avenues for designing and fabricating functional semiconductor heterostructures with tailored properties.
Collapse
Affiliation(s)
- Zhenwei Ou
- School of Physics and Technology, Center for Nanoscience and Nanotechnology, and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Wuhan University, Wuhan 430072, China
| | - Cheng Wang
- Key Laboratory of Computational Physical Sciences (Ministry of Education), Institute of Computational Physical Sciences, Fudan University, Shanghai 200433, China
| | - Zhi-Guo Tao
- Key Laboratory of Computational Physical Sciences (Ministry of Education), Institute of Computational Physical Sciences, Fudan University, Shanghai 200433, China
| | - Yahui Li
- Research Center for Industries of the Future and School of Engineering, Westlake University, Hangzhou 310030, China
| | - Zhe Li
- School of Physics and Technology, Center for Nanoscience and Nanotechnology, and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Wuhan University, Wuhan 430072, China
| | - Yan Zeng
- School of Physics and Technology, Center for Nanoscience and Nanotechnology, and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Wuhan University, Wuhan 430072, China
| | - Yan Li
- School of Physics and Technology, Center for Nanoscience and Nanotechnology, and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Wuhan University, Wuhan 430072, China
| | - Enzheng Shi
- Research Center for Industries of the Future and School of Engineering, Westlake University, Hangzhou 310030, China
| | - Weibin Chu
- Key Laboratory of Computational Physical Sciences (Ministry of Education), Institute of Computational Physical Sciences, Fudan University, Shanghai 200433, China
| | - Ti Wang
- School of Physics and Technology, Center for Nanoscience and Nanotechnology, and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Wuhan University, Wuhan 430072, China
| | - Hongxing Xu
- School of Physics and Technology, Center for Nanoscience and Nanotechnology, and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Wuhan University, Wuhan 430072, China
- School of Microelectronics, Wuhan University, Wuhan 430072, China
- Wuhan Institute of Quantum Technology, Wuhan 430206, China
| |
Collapse
|
14
|
Catanzaro A, Genco A, Louca C, Ruiz-Tijerina DA, Gillard DJ, Sortino L, Kozikov A, Alexeev EM, Pisoni R, Hague L, Watanabe K, Taniguchi T, Ensslin K, Novoselov KS, Fal'ko V, Tartakovskii AI. Resonant Band Hybridization in Alloyed Transition Metal Dichalcogenide Heterobilayers. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2309644. [PMID: 38279553 DOI: 10.1002/adma.202309644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 12/20/2023] [Indexed: 01/28/2024]
Abstract
Bandstructure engineering using alloying is widely utilized for achieving optimized performance in modern semiconductor devices. While alloying has been studied in monolayer transition metal dichalcogenides, its application in van der Waals heterostructures built from atomically thin layers is largely unexplored. Here, heterobilayers made from monolayers of WSe2 (or MoSe2) and MoxW1 - xSe2 alloy are fabricated and nontrivial tuning of the resultant bandstructure is observed as a function of concentration x. This evolution is monitored by measuring the energy of photoluminescence (PL) of the interlayer exciton (IX) composed of an electron and hole residing in different monolayers. In MoxW1 - xSe2/WSe2, a strong IX energy shift of ≈100 meV is observed for x varied from 1 to 0.6. However, for x < 0.6 this shift saturates and the IX PL energy asymptotically approaches that of the indirect bandgap in bilayer WSe2. This observation is theoretically interpreted as the strong variation of the conduction band K valley for x > 0.6, with IX PL arising from the K - K transition, while for x < 0.6, the bandstructure hybridization becomes prevalent leading to the dominating momentum-indirect K - Q transition. This bandstructure hybridization is accompanied with strong modification of IX PL dynamics and nonlinear exciton properties. This work provides foundation for bandstructure engineering in van der Waals heterostructures highlighting the importance of hybridization effects and opening a way to devices with accurately tailored electronic properties.
Collapse
Affiliation(s)
- Alessandro Catanzaro
- Department of Physics and Astronomy, The University of Sheffield, Sheffield, S3 7RH, UK
| | - Armando Genco
- Department of Physics and Astronomy, The University of Sheffield, Sheffield, S3 7RH, UK
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci, 32, Milano, 20133, Italy
| | - Charalambos Louca
- Department of Physics and Astronomy, The University of Sheffield, Sheffield, S3 7RH, UK
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci, 32, Milano, 20133, Italy
| | - David A Ruiz-Tijerina
- Departamento de Física Química, Instituto de Física, Universidad Nacional Autónoma de México, Ciudad de México, C.P., 04510, Mexico, México
| | - Daniel J Gillard
- Department of Physics and Astronomy, The University of Sheffield, Sheffield, S3 7RH, UK
| | - Luca Sortino
- Department of Physics and Astronomy, The University of Sheffield, Sheffield, S3 7RH, UK
- Chair in Hybrid Nanosystems, Nanoinstitute Munich, Faculty of Physics, Ludwig-Maximilians-Universität München, 80539, Munich, Germany
| | - Aleksey Kozikov
- Department of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, UK
- School of Mathematics, Statistics and Physics, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
| | - Evgeny M Alexeev
- Department of Physics and Astronomy, The University of Sheffield, Sheffield, S3 7RH, UK
- Cambridge Graphene Centre, University of Cambridge, 9 J. J. Thomson Avenue, Cambridge, CB3 0FA, UK
| | - Riccardo Pisoni
- Solid State Physics Laboratory, ETH Zurich, Zurich, CH-8093, Switzerland
| | - Lee Hague
- National Graphene Institute, University of Manchester, Manchester, M13 9PL, UK
| | - Kenji Watanabe
- Research Center for Electronic and Optical Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Takashi Taniguchi
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Klaus Ensslin
- Solid State Physics Laboratory, ETH Zurich, Zurich, CH-8093, Switzerland
| | - Kostya S Novoselov
- Institute for Functional Intelligent Materials, National University of Singapore, Singapore, 117546, Singapore
| | - Vladimir Fal'ko
- Department of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, UK
- Henry Royce Institute for Advanced Materials, University of Manchester, Manchester, M13 9PL, United Kingdom
| | | |
Collapse
|
15
|
Graml M, Zollner K, Hernangómez-Pérez D, Faria Junior PE, Wilhelm J. Low-Scaling GW Algorithm Applied to Twisted Transition-Metal Dichalcogenide Heterobilayers. J Chem Theory Comput 2024; 20:2202-2208. [PMID: 38353944 PMCID: PMC10938508 DOI: 10.1021/acs.jctc.3c01230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 12/30/2023] [Accepted: 01/08/2024] [Indexed: 03/13/2024]
Abstract
The GW method is widely used for calculating the electronic band structure of materials. The high computational cost of GW algorithms prohibits their application to many systems of interest. We present a periodic, low-scaling, and highly efficient GW algorithm that benefits from the locality of the Gaussian basis and the polarizability. The algorithm enables G0W0 calculations on a MoSe2/WS2 bilayer with 984 atoms per unit cell, in 42 h using 1536 cores. This is 4 orders of magnitude faster than a plane-wave G0W0 algorithm, allowing for unprecedented computational studies of electronic excitations at the nanoscale.
Collapse
Affiliation(s)
- Maximilian Graml
- Institute
of Theoretical Physics, University of Regensburg, 93053 Regensburg, Germany
- Regensburg
Center for Ultrafast Nanoscopy (RUN), University
of Regensburg, 93053 Regensburg, Germany
| | - Klaus Zollner
- Institute
of Theoretical Physics, University of Regensburg, 93053 Regensburg, Germany
| | - Daniel Hernangómez-Pérez
- Department
of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Paulo E. Faria Junior
- Institute
of Theoretical Physics, University of Regensburg, 93053 Regensburg, Germany
| | - Jan Wilhelm
- Institute
of Theoretical Physics, University of Regensburg, 93053 Regensburg, Germany
- Regensburg
Center for Ultrafast Nanoscopy (RUN), University
of Regensburg, 93053 Regensburg, Germany
| |
Collapse
|
16
|
Polovnikov B, Scherzer J, Misra S, Huang X, Mohl C, Li Z, Göser J, Förste J, Bilgin I, Watanabe K, Taniguchi T, Högele A, Baimuratov AS. Field-Induced Hybridization of Moiré Excitons in MoSe_{2}/WS_{2} Heterobilayers. PHYSICAL REVIEW LETTERS 2024; 132:076902. [PMID: 38427888 DOI: 10.1103/physrevlett.132.076902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 01/19/2024] [Indexed: 03/03/2024]
Abstract
We study experimentally and theoretically the hybridization among intralayer and interlayer moiré excitons in a MoSe_{2}/WS_{2} heterostructure with antiparallel alignment. Using a dual-gate device and cryogenic white light reflectance and narrow-band laser modulation spectroscopy, we subject the moiré excitons in the MoSe_{2}/WS_{2} heterostack to a perpendicular electric field, monitor the field-induced dispersion and hybridization of intralayer and interlayer moiré exciton states, and induce a crossover from type I to type II band alignment. Moreover, we employ perpendicular magnetic fields to map out the dependence of the corresponding exciton Landé g factors on the electric field. Finally, we develop an effective theoretical model combining resonant and nonresonant contributions to moiré potentials to explain the observed phenomenology, and highlight the relevance of interlayer coupling for structures with close energetic band alignment as in MoSe_{2}/WS_{2}.
Collapse
Affiliation(s)
- Borislav Polovnikov
- Fakultät für Physik, Munich Quantum Center, and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Geschwister-Scholl-Platz 1, 80539 München, Germany
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Straße 1, 85748 Garching bei München, Germany
| | - Johannes Scherzer
- Fakultät für Physik, Munich Quantum Center, and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Geschwister-Scholl-Platz 1, 80539 München, Germany
| | - Subhradeep Misra
- Fakultät für Physik, Munich Quantum Center, and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Geschwister-Scholl-Platz 1, 80539 München, Germany
| | - Xin Huang
- Fakultät für Physik, Munich Quantum Center, and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Geschwister-Scholl-Platz 1, 80539 München, Germany
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, CAS Key Laboratory of Vacuum Physics, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Christian Mohl
- Fakultät für Physik, Munich Quantum Center, and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Geschwister-Scholl-Platz 1, 80539 München, Germany
| | - Zhijie Li
- Fakultät für Physik, Munich Quantum Center, and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Geschwister-Scholl-Platz 1, 80539 München, Germany
| | - Jonas Göser
- Fakultät für Physik, Munich Quantum Center, and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Geschwister-Scholl-Platz 1, 80539 München, Germany
| | - Jonathan Förste
- Fakultät für Physik, Munich Quantum Center, and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Geschwister-Scholl-Platz 1, 80539 München, Germany
| | - Ismail Bilgin
- Fakultät für Physik, Munich Quantum Center, and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Geschwister-Scholl-Platz 1, 80539 München, Germany
| | - Kenji Watanabe
- Research Center for Electronic and Optical Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Alexander Högele
- Fakultät für Physik, Munich Quantum Center, and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Geschwister-Scholl-Platz 1, 80539 München, Germany
- Munich Center for Quantum Science and Technology (MCQST), Schellingstraße 4, 80799 München, Germany
| | - Anvar S Baimuratov
- Fakultät für Physik, Munich Quantum Center, and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Geschwister-Scholl-Platz 1, 80539 München, Germany
| |
Collapse
|
17
|
Blundo E, Tuzi F, Cianci S, Cuccu M, Olkowska-Pucko K, Kipczak Ł, Contestabile G, Miriametro A, Felici M, Pettinari G, Taniguchi T, Watanabe K, Babiński A, Molas MR, Polimeni A. Localisation-to-delocalisation transition of moiré excitons in WSe 2/MoSe 2 heterostructures. Nat Commun 2024; 15:1057. [PMID: 38316753 PMCID: PMC10844653 DOI: 10.1038/s41467-024-44739-9] [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: 04/24/2023] [Accepted: 01/02/2024] [Indexed: 02/07/2024] Open
Abstract
Moiré excitons (MXs) are electron-hole pairs localised by the periodic (moiré) potential forming in two-dimensional heterostructures (HSs). MXs can be exploited, e.g., for creating nanoscale-ordered quantum emitters and achieving or probing strongly correlated electronic phases at relatively high temperatures. Here, we studied the exciton properties of WSe2/MoSe2 HSs from T = 6 K to room temperature using time-resolved and continuous-wave micro-photoluminescence also under a magnetic field. The exciton dynamics and emission lineshape evolution with temperature show clear signatures that MXs de-trap from the moiré potential and turn into free interlayer excitons (IXs) for temperatures above 100 K. The MX-to-IX transition is also apparent from the exciton magnetic moment reversing its sign when the moiré potential is not capable of localising excitons at elevated temperatures. Concomitantly, the exciton formation and decay times reduce drastically. Thus, our findings establish the conditions for a truly confined nature of the exciton states in a moiré superlattice with increasing temperature and photo-generated carrier density.
Collapse
Affiliation(s)
- Elena Blundo
- Physics Department, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy.
| | - Federico Tuzi
- Physics Department, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy
| | - Salvatore Cianci
- Physics Department, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy
| | - Marzia Cuccu
- Physics Department, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy
| | - Katarzyna Olkowska-Pucko
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093, Warsaw, Poland
| | - Łucja Kipczak
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093, Warsaw, Poland
| | - Giorgio Contestabile
- Physics Department, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy
| | - Antonio Miriametro
- Physics Department, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy
| | - Marco Felici
- Physics Department, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy
| | - Giorgio Pettinari
- Institute for Photonics and Nanotechnologies, National Research Council, 00133, Rome, Italy
| | - 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
| | - Adam Babiński
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093, Warsaw, Poland
| | - Maciej R Molas
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093, Warsaw, Poland
| | - Antonio Polimeni
- Physics Department, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy.
| |
Collapse
|
18
|
Lin KQ, Faria Junior PE, Hübner R, Ziegler JD, Bauer JM, Buchner F, Florian M, Hofmann F, Watanabe K, Taniguchi T, Fabian J, Steinhoff A, Chernikov A, Bange S, Lupton JM. Ultraviolet interlayer excitons in bilayer WSe 2. NATURE NANOTECHNOLOGY 2024; 19:196-201. [PMID: 38049597 DOI: 10.1038/s41565-023-01544-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 10/15/2023] [Indexed: 12/06/2023]
Abstract
Interlayer excitons in van der Waals heterostructures are fascinating for applications like exciton condensation, excitonic devices and moiré-induced quantum emitters. The study of these charge-transfer states has almost exclusively focused on band edges, limiting the spectral region to the near-infrared regime. Here we explore the above-gap analogues of interlayer excitons in bilayer WSe2 and identify both neutral and charged species emitting in the ultraviolet. Even though the transitions occur far above the band edge, the states remain metastable, exhibiting linewidths as narrow as 1.8 meV. These interlayer high-lying excitations have switchable dipole orientations and hence show prominent Stark splitting. The positive and negative interlayer high-lying trions exhibit significant binding energies of 20-30 meV, allowing for a broad tunability of transitions via electric fields and electrostatic doping. The Stark splitting of these trions serves as a highly accurate, built-in sensor for measuring interlayer electric field strengths, which are exceedingly difficult to quantify otherwise. Such excitonic complexes are further sensitive to the interlayer twist angle and offer opportunities to explore emergent moiré physics under electrical control. Our findings more than double the accessible energy range for applications based on interlayer excitons.
Collapse
Affiliation(s)
- Kai-Qiang Lin
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China.
- Department of Physics, University of Regensburg, Regensburg, Germany.
| | | | - Ruven Hübner
- Institute for Theoretical Physics and Bremen Center for Computational Materials Science, University of Bremen, Bremen, Germany
| | - Jonas D Ziegler
- Institute of Applied Physics and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, Dresden, Germany
| | - Jonas M Bauer
- Department of Physics, University of Regensburg, Regensburg, Germany
| | - Fabian Buchner
- Department of Physics, University of Regensburg, Regensburg, Germany
| | - Matthias Florian
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, USA
| | - Felix Hofmann
- Department of Physics, University of Regensburg, Regensburg, Germany
| | - Kenji Watanabe
- Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
| | - Jaroslav Fabian
- Department of Physics, University of Regensburg, Regensburg, Germany
| | - Alexander Steinhoff
- Institute for Theoretical Physics and Bremen Center for Computational Materials Science, University of Bremen, Bremen, Germany
| | - Alexey Chernikov
- Institute of Applied Physics and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, Dresden, Germany
| | - Sebastian Bange
- Department of Physics, University of Regensburg, Regensburg, Germany
| | - John M Lupton
- Department of Physics, University of Regensburg, Regensburg, Germany
| |
Collapse
|
19
|
Song J, Sun M. Modulating Thermoelectric Properties of the MoSe 2/WSe 2 Superlattice Heterostructure by Twist Angles. ACS APPLIED MATERIALS & INTERFACES 2024; 16:3325-3333. [PMID: 38190725 DOI: 10.1021/acsami.3c15160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2024]
Abstract
In the current era of limited resources, the matter of energy conversion holds significant importance. Thermoelectric materials possess the ability to transform thermal energy into electric power. Achieving an impressive thermoelectric figure of merit (ZT) necessitates the presence of a high power factor alongside low thermal conductivity. Stimulated by recent experimental reports on the in-plane lateral MoSe2/WSe2 heterostructure in the application thermoelectric device [Zhang Y. et al., Simultaneous electrical and thermal rectification in a monolayer lateral heterojunction. Science 2022, 378, 169], in this study, the method of twisting angle is used to modulate the energy bands of van der Waals MoSe2/WSe2 superlattice heterostructures to optimize the carrier concentration, band gap, electric conductance, thermal conductivity, and ZT of the heterostructure. The 21.79° twisted heterostructures among different twisting-angle heterostructures benefit from both the high power factor and low thermal conductivity, ultimately leading to significantly improved ZT compared to the untwisted counterpart.
Collapse
Affiliation(s)
- Jizhe Song
- School of Mathematics and Physics, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Mengtao Sun
- School of Mathematics and Physics, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
| |
Collapse
|
20
|
Tran TT, Lee Y, Roy S, Tran TU, Kim Y, Taniguchi T, Watanabe K, Milošević MV, Lim SC, Chaves A, Jang JI, Kim J. Synergetic Enhancement of Quantum Yield and Exciton Lifetime of Monolayer WS 2 by Proximal Metal Plate and Negative Electric Bias. ACS NANO 2024; 18:220-228. [PMID: 38127273 DOI: 10.1021/acsnano.3c05667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
The efficiency of light emission is a critical performance factor for monolayer transition metal dichalcogenides (1L-TMDs) for photonic applications. While various methods have been studied to compensate for lattice defects to improve the quantum yield (QY) of 1L-TMDs, exciton-exciton annihilation (EEA) is still a major nonradiative decay channel for excitons at high exciton densities. Here, we demonstrate that the combined use of a proximal Au plate and a negative electric gate bias (NEGB) for 1L-WS2 provides a dramatic enhancement of the exciton lifetime at high exciton densities with the corresponding QY enhanced by 30 times and the EEA rate constant decreased by 80 times. The suppression of EEA by NEGB is attributed to the reduction of the defect-assisted EEA process, which we also explain with our theoretical model. Our results provide a synergetic solution to cope with EEA to realize high-intensity 2D light emitters using TMDs.
Collapse
Affiliation(s)
- Trang Thu Tran
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Yongjun Lee
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Shrawan Roy
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Thi Uyen Tran
- Department of Smart Fab. Technology, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Youngbum Kim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Takashi Taniguchi
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Kenji Watanabe
- Research Center for Electronic and Optical Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Milorad V Milošević
- Department of Physics, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium
- Instituto de Física, Universidade Federal de Mato Grosso, Cuiabá, Mato Grosso 78060-900, Brazil
| | - Seong Chu Lim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
- Department of Smart Fab. Technology, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Andrey Chaves
- Department of Physics, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium
- Departamento de Física, Universidade Federal do Ceará, Campus do Pici, C.P. 6030, 60455-900 Fortaleza, Ceará, Brazil
| | - Joon I Jang
- Department of Physics, Sogang University, Seoul 04107, Republic of Korea
| | - Jeongyong Kim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| |
Collapse
|
21
|
Wietek E, Florian M, Göser J, Taniguchi T, Watanabe K, Högele A, Glazov MM, Steinhoff A, Chernikov A. Nonlinear and Negative Effective Diffusivity of Interlayer Excitons in Moiré-Free Heterobilayers. PHYSICAL REVIEW LETTERS 2024; 132:016202. [PMID: 38242648 DOI: 10.1103/physrevlett.132.016202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 11/10/2023] [Indexed: 01/21/2024]
Abstract
Interlayer exciton diffusion is studied in atomically reconstructed MoSe_{2}/WSe_{2} heterobilayers with suppressed disorder. Local atomic registry is confirmed by characteristic optical absorption, circularly polarized photoluminescence, and g-factor measurements. Using transient microscopy we observe propagation properties of interlayer excitons that are independent from trapping at moiré- or disorder-induced local potentials. Confirmed by characteristic temperature dependence for free particles, linear diffusion coefficients of interlayer excitons at liquid helium temperature and low excitation densities are almost 1000 times higher than in previous observations. We further show that exciton-exciton repulsion and annihilation contribute nearly equally to nonlinear propagation by disentangling the two processes in the experiment and simulations. Finally, we demonstrate effective shrinking of the light emission area over time across several hundreds of picoseconds at the transition from exciton- to the plasma-dominated regimes. Supported by microscopic calculations for band gap renormalization to identify the Mott threshold, this indicates transient crossing between rapidly expanding, short-lived electron-hole plasma and slower, long-lived exciton populations.
Collapse
Affiliation(s)
- Edith Wietek
- Institute of Applied Physics and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany
| | - Matthias Florian
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Jonas Göser
- Fakultät für Physik, Munich Quantum Center, and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, 80539 München, Germany
| | - Takashi Taniguchi
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Kenji Watanabe
- Research Center for Electronic and Optical Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Alexander Högele
- Fakultät für Physik, Munich Quantum Center, and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, 80539 München, Germany
- Munich Center for Quantum Science and Technology (MCQST), 80799 München, Germany
| | | | - Alexander Steinhoff
- Institut für Theoretische Physik, Universität Bremen, 28334 Bremen, Germany
- Bremen Center for Computational Materials Science, Universität Bremen, 28334 Bremen, Germany
| | - Alexey Chernikov
- Institute of Applied Physics and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany
| |
Collapse
|
22
|
Kang H, Ma J, Li J, Zhang X, Liu X. Exciton Polaritons in Emergent Two-Dimensional Semiconductors. ACS NANO 2023; 17:24449-24467. [PMID: 38051774 DOI: 10.1021/acsnano.3c07993] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
The "marriage" of light (i.e., photon) and matter (i.e., exciton) in semiconductors leads to the formation of hybrid quasiparticles called exciton polaritons with fascinating quantum phenomena such as Bose-Einstein condensation (BEC) and photon blockade. The research of exciton polaritons has been evolving into an era with emergent two-dimensional (2D) semiconductors and photonic structures for their tremendous potential to break the current limitations of quantum fundamental study and photonic applications. In this Perspective, the basic concepts of 2D excitons, optical resonators, and the strong coupling regime are introduced. The research progress of exciton polaritons is reviewed, and important discoveries (especially the recent ones of 2D exciton polaritons) are highlighted. Subsequently, the emergent 2D exciton polaritons are discussed in detail, ranging from the realization of the strong coupling regime in various photonic systems to the discoveries of attractive phenomena with interesting physics and extensive applications. Moreover, emerging 2D semiconductors, such as 2D perovskites (2DPK) and 2D antiferromagnetic (AFM) semiconductors, are surveyed for the manipulation of exciton polaritons with distinct control degrees of freedom (DOFs). Finally, the outlook on the 2D exciton polaritons and their nonlinear interactions is presented with our initial numerical simulations. This Perspective not only aims to provide an in-depth overview of the latest fundamental findings in 2D exciton polaritons but also attempts to serve as a valuable resource to prospect explorations of quantum optics and topological photonic applications.
Collapse
Affiliation(s)
- Haifeng Kang
- Key Laboratory of Artificial Micro/Nano Structure of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan, 430072, P. R. China
| | - Jingwen Ma
- Faculty of Science and Engineering, The University of Hong Kong, Hong Kong, SAR, P. R. China
| | - Junyu Li
- Key Laboratory of Artificial Micro/Nano Structure of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan, 430072, P. R. China
| | - Xiang Zhang
- Faculty of Science and Engineering, The University of Hong Kong, Hong Kong, SAR, P. R. China
- Department of Physics, The University of Hong Kong, Hong Kong, SAR, P. R. China
| | - Xiaoze Liu
- Key Laboratory of Artificial Micro/Nano Structure of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan, 430072, P. R. China
- Wuhan Institute of Quantum Technology, Wuhan, 430206, P. R. China
- Wuhan University Shenzhen Research Institute, Shenzhen, 518057, P. R. China
| |
Collapse
|
23
|
Li Z, Qin F, Ong CS, Huang J, Xu Z, Chen P, Qiu C, Zhang X, Zhang C, Zhang X, Eriksson O, Rubio A, Tang P, Yuan H. Robustness of Trion State in Gated Monolayer MoSe 2 under Pressure. NANO LETTERS 2023; 23:10282-10289. [PMID: 37906179 DOI: 10.1021/acs.nanolett.3c02812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Quasiparticles consisting of correlated electron(s) and hole(s), such as excitons and trions, play important roles in the optical phenomena of van der Waals semiconductors and serve as unique platforms for studies of many-body physics. Herein, we report a gate-tunable exciton-to-trion transition in pressurized monolayer MoSe2, in which the electronic band structures are modulated continuously within a diamond anvil cell. The emission energies of both the exciton and trion undergo large blueshifts over 90 meV with increasing pressure. Surprisingly, the trion binding energy remains constant at 30 meV, regardless of the applied pressure. Combining ab initio density functional theory calculations and quantum Monte Carlo simulations, we find that the remarkable robustness of the trion binding energy originates from the spatially diffused nature of the trion wave function and the weak correlation between its constituent electron-hole pairs. Our findings shed light on the optical properties of correlated excitonic quasiparticles in low-dimensional materials.
Collapse
Affiliation(s)
- Zeya Li
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
- College of Engineering and Applied Sciences, Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210023, China
| | - Feng Qin
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
- College of Engineering and Applied Sciences, Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210023, China
| | - Chin Shen Ong
- Department of Physics and Astronomy, Uppsala University, Uppsala 75120, Sweden
| | - Junwei Huang
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
- College of Engineering and Applied Sciences, Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210023, China
| | - Zian Xu
- School of Materials Science and Engineering, Beihang University, Beijing 100191, China
| | - Peng Chen
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
- College of Engineering and Applied Sciences, Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210023, China
| | - Caiyu Qiu
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
- College of Engineering and Applied Sciences, Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210023, China
| | - Xi Zhang
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
- School of Physics, Nanjing University, Nanjing 210000, China
| | - Caorong Zhang
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
- School of Physics, Nanjing University, Nanjing 210000, China
| | - Xiuxiu Zhang
- School of Materials Science and Engineering, Beihang University, Beijing 100191, China
| | - Olle Eriksson
- Department of Physics and Astronomy, Uppsala University, Uppsala 75120, Sweden
- School of Science and Technology, Örebro University, Örebro 70182, Sweden
| | - Angel Rubio
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free-Electron Laser Science, Hamburg 22761, Germany
- Center for Computational Quantum Physics, Simons Foundation Flatiron Institute, New York 10010, United States
- Nano-Bio Spectroscopy Group, University of the Basque Country (UPV/EHU), San Sebastián 20018, Spain
| | - Peizhe Tang
- School of Materials Science and Engineering, Beihang University, Beijing 100191, China
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free-Electron Laser Science, Hamburg 22761, Germany
| | - Hongtao Yuan
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
- College of Engineering and Applied Sciences, Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210023, China
| |
Collapse
|
24
|
Moradifar P, Liu Y, Shi J, Siukola Thurston ML, Utzat H, van Driel TB, Lindenberg AM, Dionne JA. Accelerating Quantum Materials Development with Advances in Transmission Electron Microscopy. Chem Rev 2023. [PMID: 37979189 DOI: 10.1021/acs.chemrev.2c00917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2023]
Abstract
Quantum materials are driving a technology revolution in sensing, communication, and computing, while simultaneously testing many core theories of the past century. Materials such as topological insulators, complex oxides, superconductors, quantum dots, color center-hosting semiconductors, and other types of strongly correlated materials can exhibit exotic properties such as edge conductivity, multiferroicity, magnetoresistance, superconductivity, single photon emission, and optical-spin locking. These emergent properties arise and depend strongly on the material's detailed atomic-scale structure, including atomic defects, dopants, and lattice stacking. In this review, we describe how progress in the field of electron microscopy (EM), including in situ and in operando EM, can accelerate advances in quantum materials and quantum excitations. We begin by describing fundamental EM principles and operation modes. We then discuss various EM methods such as (i) EM spectroscopies, including electron energy loss spectroscopy (EELS), cathodoluminescence (CL), and electron energy gain spectroscopy (EEGS); (ii) four-dimensional scanning transmission electron microscopy (4D-STEM); (iii) dynamic and ultrafast EM (UEM); (iv) complementary ultrafast spectroscopies (UED, XFEL); and (v) atomic electron tomography (AET). We describe how these methods could inform structure-function relations in quantum materials down to the picometer scale and femtosecond time resolution, and how they enable precision positioning of atomic defects and high-resolution manipulation of quantum materials. For each method, we also describe existing limitations to solve open quantum mechanical questions, and how they might be addressed to accelerate progress. Among numerous notable results, our review highlights how EM is enabling identification of the 3D structure of quantum defects; measuring reversible and metastable dynamics of quantum excitations; mapping exciton states and single photon emission; measuring nanoscale thermal transport and coupled excitation dynamics; and measuring the internal electric field and charge density distribution of quantum heterointerfaces- all at the quantum materials' intrinsic atomic and near atomic-length scale. We conclude by describing open challenges for the future, including achieving stable sample holders for ultralow temperature (below 10K) atomic-scale spatial resolution, stable spectrometers that enable meV energy resolution, and high-resolution, dynamic mapping of magnetic and spin fields. With atomic manipulation and ultrafast characterization enabled by EM, quantum materials will be poised to integrate into many of the sustainable and energy-efficient technologies needed for the 21st century.
Collapse
Affiliation(s)
- Parivash Moradifar
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
| | - Yin Liu
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Jiaojian Shi
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road MS69, Menlo Park, California 94025, United States
| | | | - Hendrik Utzat
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
- Department of Chemistry, University of California Berkeley, Berkeley, California 94720, United States
| | - Tim B van Driel
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, United States
| | - Aaron M Lindenberg
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road MS69, Menlo Park, California 94025, United States
| | - Jennifer A Dionne
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
- Department of Radiology, Stanford University, Stanford, California 94305, United States
| |
Collapse
|
25
|
Policht VR, Mittenzwey H, Dogadov O, Katzer M, Villa A, Li Q, Kaiser B, Ross AM, Scotognella F, Zhu X, Knorr A, Selig M, Cerullo G, Dal Conte S. Time-domain observation of interlayer exciton formation and thermalization in a MoSe 2/WSe 2 heterostructure. Nat Commun 2023; 14:7273. [PMID: 37949848 PMCID: PMC10638375 DOI: 10.1038/s41467-023-42915-x] [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: 04/17/2023] [Accepted: 10/26/2023] [Indexed: 11/12/2023] Open
Abstract
Vertical heterostructures of transition metal dichalcogenides (TMDs) host interlayer excitons with electrons and holes residing in different layers. With respect to their intralayer counterparts, interlayer excitons feature longer lifetimes and diffusion lengths, paving the way for room temperature excitonic optoelectronic devices. The interlayer exciton formation process and its underlying physical mechanisms are largely unexplored. Here we use ultrafast transient absorption spectroscopy with a broadband white-light probe to simultaneously resolve interlayer charge transfer and interlayer exciton formation dynamics in a MoSe2/WSe2 heterostructure. We observe an interlayer exciton formation timescale nearly an order of magnitude (~1 ps) longer than the interlayer charge transfer time (~100 fs). Microscopic calculations attribute this relative delay to an interplay of a phonon-assisted interlayer exciton cascade and thermalization, and excitonic wave-function overlap. Our results may explain the efficient photocurrent generation observed in optoelectronic devices based on TMD heterostructures, as the interlayer excitons are able to dissociate during thermalization.
Collapse
Affiliation(s)
- Veronica R Policht
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, Milano, 20133, Italy.
- NRC Postdoc residing at U.S. Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, DC, 20375, USA.
| | - Henry Mittenzwey
- Institut für Theoretische Physik, Nichtlineare Optik und Quantenelektronik, Technische Universität Berlin, Hardenbergstraße 36, 10623, Berlin, Germany.
| | - Oleg Dogadov
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, Milano, 20133, Italy
| | - Manuel Katzer
- Institut für Theoretische Physik, Nichtlineare Optik und Quantenelektronik, Technische Universität Berlin, Hardenbergstraße 36, 10623, Berlin, Germany
| | - Andrea Villa
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, Milano, 20133, Italy
| | - Qiuyang Li
- Department of Chemistry, Columbia University, 3000 Broadway, New York, NY, 10027, USA
| | | | - Aaron M Ross
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, Milano, 20133, Italy
| | - Francesco Scotognella
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, Milano, 20133, Italy
- Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, Torino, 10129, Italy
| | - Xiaoyang Zhu
- Department of Chemistry, Columbia University, 3000 Broadway, New York, NY, 10027, USA
| | - Andreas Knorr
- Institut für Theoretische Physik, Nichtlineare Optik und Quantenelektronik, Technische Universität Berlin, Hardenbergstraße 36, 10623, Berlin, Germany
| | - Malte Selig
- Institut für Theoretische Physik, Nichtlineare Optik und Quantenelektronik, Technische Universität Berlin, Hardenbergstraße 36, 10623, Berlin, Germany
| | - Giulio Cerullo
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, Milano, 20133, Italy
- CNR-IFN, Piazza Leonardo da Vinci 32, Milano, 20133, Italy
| | - Stefano Dal Conte
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, Milano, 20133, Italy.
| |
Collapse
|
26
|
Fang H, Lin Q, Zhang Y, Thompson J, Xiao S, Sun Z, Malic E, Dash SP, Wieczorek W. Localization and interaction of interlayer excitons in MoSe 2/WSe 2 heterobilayers. Nat Commun 2023; 14:6910. [PMID: 37903787 PMCID: PMC10616232 DOI: 10.1038/s41467-023-42710-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 10/19/2023] [Indexed: 11/01/2023] Open
Abstract
Transition metal dichalcogenide (TMD) heterobilayers provide a versatile platform to explore unique excitonic physics via the properties of the constituent TMDs and external stimuli. Interlayer excitons (IXs) can form in TMD heterobilayers as delocalized or localized states. However, the localization of IX in different types of potential traps, the emergence of biexcitons in the high-excitation regime, and the impact of potential traps on biexciton formation have remained elusive. In our work, we observe two types of potential traps in a MoSe2/WSe2 heterobilayer, which result in significantly different emission behavior of IXs at different temperatures. We identify the origin of these traps as localized defect states and the moiré potential of the TMD heterobilayer. Furthermore, with strong excitation intensity, a superlinear emission behavior indicates the emergence of interlayer biexcitons, whose formation peaks at a specific temperature. Our work elucidates the different excitation and temperature regimes required for the formation of both localized and delocalized IX and biexcitons and, thus, contributes to a better understanding and application of the rich exciton physics in TMD heterostructures.
Collapse
Affiliation(s)
- Hanlin Fang
- Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, 41296, Gothenburg, Sweden.
| | - Qiaoling Lin
- Department of Electrical and Photonics Engineering, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark
| | - Yi Zhang
- Department of Electronics and Nanoengineering and QTF Centre of Excellence, Aalto University, Espoo, 02150, Finland
| | - Joshua Thompson
- Department of Physics, Philipps-Universität Marburg, 35037, Marburg, Germany
| | - Sanshui Xiao
- Department of Electrical and Photonics Engineering, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark
| | - Zhipei Sun
- Department of Electronics and Nanoengineering and QTF Centre of Excellence, Aalto University, Espoo, 02150, Finland
| | - Ermin Malic
- Department of Physics, Philipps-Universität Marburg, 35037, Marburg, Germany
| | - Saroj P Dash
- Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, 41296, Gothenburg, Sweden
| | - Witlef Wieczorek
- Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, 41296, Gothenburg, Sweden.
| |
Collapse
|
27
|
Zhang Z, Zhang B, Wang Y, Wang M, Zhang Y, Li H, Zhang J, Song A. Toward High-Peak-to-Valley-Ratio Graphene Resonant Tunneling Diodes. NANO LETTERS 2023; 23:8132-8139. [PMID: 37668256 PMCID: PMC10510586 DOI: 10.1021/acs.nanolett.3c02281] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 08/27/2023] [Indexed: 09/06/2023]
Abstract
The resonant tunneling diode (RTD) is one of the very few room-temperature-operating quantum devices to date that is able to exhibit negative differential resistance. However, the reported key figure of merit, the current peak-to-valley ratio (PVR), of graphene RTDs has been up to only 3.9 at room temperature thus far. This remains very puzzling, given the atomically flat interfaces of the 2D materials. By varying the active area and perimeter of RTDs based on a graphene/hexagonal boron nitride/graphene heterostructure, we discovered that the edge doping can play a dominant role in determining the resonant tunneling, and a large area-to-perimeter ratio is necessary to obtain a high PVR. The understanding enables establishing a novel design rule and results in a PVR of 14.9, which is at least a factor of 3.8 higher than previously reported graphene RTDs. Furthermore, a theory is developed allowing extraction of the edge doping depth for the first time.
Collapse
Affiliation(s)
- Zihao Zhang
- Shandong
Technology Center of Nanodevices and Integration, School of Microelectronics, Shandong University, Jinan 250100, China
| | - Baoqing Zhang
- Shandong
Technology Center of Nanodevices and Integration, School of Microelectronics, Shandong University, Jinan 250100, China
| | - Yiming Wang
- Shandong
Technology Center of Nanodevices and Integration, School of Microelectronics, Shandong University, Jinan 250100, China
| | - Mingyang Wang
- Shandong
Technology Center of Nanodevices and Integration, School of Microelectronics, Shandong University, Jinan 250100, China
| | - Yifei Zhang
- Shandong
Technology Center of Nanodevices and Integration, School of Microelectronics, Shandong University, Jinan 250100, China
| | - Hu Li
- Shandong
Technology Center of Nanodevices and Integration, School of Microelectronics, Shandong University, Jinan 250100, China
| | - Jiawei Zhang
- Shandong
Technology Center of Nanodevices and Integration, School of Microelectronics, Shandong University, Jinan 250100, China
- Suzhou
Research Institute, Shandong University, Suzhou 215123, China
| | - Aimin Song
- Shandong
Technology Center of Nanodevices and Integration, School of Microelectronics, Shandong University, Jinan 250100, China
- Department
of Electrical and Electronic Engineering, University of Manchester, Manchester M13 9PL, United
Kingdom
| |
Collapse
|
28
|
Hsieh YC, Lin ZY, Fung SJ, Lu WS, Ho SC, Hong SP, Ho SZ, Huang CH, Watanabe K, Taniguchi T, Chan YH, Chen YC, Wu CL, Chen TM. Engineering the Strain and Interlayer Excitons of 2D Materials via Lithographically Engraved Hexagonal Boron Nitride. NANO LETTERS 2023; 23:7244-7251. [PMID: 37348137 DOI: 10.1021/acs.nanolett.3c01208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/24/2023]
Abstract
Strain engineering has quickly emerged as a viable option to modify the electronic, optical, and magnetic properties of 2D materials. However, it remains challenging to arbitrarily control the strain. Here we show that, by creating atomically flat surface nanostructures in hexagonal boron nitride, we achieve an arbitrary on-chip control of both the strain distribution and magnitude on high-quality molybdenum disulfide. The phonon and exciton emissions are shown to vary in accordance with our strain field designs, enabling us to write and draw any photoluminescence color image in a single chip. Moreover, our strain engineering offers a powerful means to significantly and controllably alter the strengths and energies of interlayer excitons at room temperature. This method can be easily extended to other material systems and offers promise for functional excitonic devices.
Collapse
Affiliation(s)
- Yu-Chiang Hsieh
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Zhen-You Lin
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Shin-Ji Fung
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Wen-Shin Lu
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
| | - Sheng-Chin Ho
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Siang-Ping Hong
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Sheng-Zhu Ho
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Chiu-Hua Huang
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Namiki 1-1, Tsukuba, 305-0044, Ibaraki, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Namiki 1-1, Tsukuba, 305-0044, Ibaraki, Japan
| | - Yang-Hao Chan
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan
- Physics Division, National Center for Theoretical Sciences, Taipei 106, Taiwan
| | - Yi-Chun Chen
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
- Center for Quantum Frontiers of Research & Technology (QFort), National Cheng Kung University, Tainan 701, Taiwan
| | - Chung-Lin Wu
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
- Center for Quantum Frontiers of Research & Technology (QFort), National Cheng Kung University, Tainan 701, Taiwan
| | - Tse-Ming Chen
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
- Center for Quantum Frontiers of Research & Technology (QFort), National Cheng Kung University, Tainan 701, Taiwan
| |
Collapse
|
29
|
Chen J, Yue X, Shan Y, Wang H, Han J, Wang H, Sheng C, Hu L, Liu R, Yang W, Qiu ZJ, Cong C. Twist-angle-dependent momentum-space direct and indirect interlayer excitons in WSe 2/WS 2 heterostructure. RSC Adv 2023; 13:18099-18107. [PMID: 37323440 PMCID: PMC10267672 DOI: 10.1039/d3ra02952b] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 05/29/2023] [Indexed: 06/17/2023] Open
Abstract
Interlayer excitons (ILEs) in the van der Waals (vdW) heterostructures of type-II band alignment transition metal dichalcogenides (TMDCs) have attracted significant interest owing to their unique exciton properties and potential in quantum information applications. However, the new dimension that emerges with the stacking of structures with a twist angle leads to a more complex fine structure of ILEs, presenting both an opportunity and a challenge for the regulation of the interlayer excitons. In this study, we report the evolution of interlayer excitons with the twist angle in the WSe2/WS2 heterostructure and identify the direct (indirect) interlayer excitons by combining photoluminescence (PL) and density functional theory (DFT) calculations. Two interlayer excitons with opposite circular polarization assigned to the different transition paths of K-K and Q-K were observed. The nature of the direct (indirect) interlayer exciton was confirmed by circular polarization PL measurement, excitation power-dependent PL measurement and DFT calculations. Furthermore, by applying an external electric field to regulate the band structure of the WSe2/WS2 heterostructure and control the transition path of the interlayer excitons, we could successfully realize the regulation of interlayer exciton emission. This study provides more evidence for the twist-angle-based control of heterostructure properties.
Collapse
Affiliation(s)
- Jiajun Chen
- State Key Laboratory of ASIC & System, School of Information Science and Technology, Fudan University Shanghai 200433 China
| | - Xiaofei Yue
- State Key Laboratory of ASIC & System, School of Information Science and Technology, Fudan University Shanghai 200433 China
| | - Yabing Shan
- State Key Laboratory of ASIC & System, School of Information Science and Technology, Fudan University Shanghai 200433 China
| | - Huishan Wang
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences Changning Road 865 Shanghai 200050 China
| | - Jinkun Han
- State Key Laboratory of ASIC & System, School of Information Science and Technology, Fudan University Shanghai 200433 China
| | - Haomin Wang
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences Changning Road 865 Shanghai 200050 China
| | - Chenxu Sheng
- State Key Laboratory of ASIC & System, School of Information Science and Technology, Fudan University Shanghai 200433 China
| | - Laigui Hu
- State Key Laboratory of ASIC & System, School of Information Science and Technology, Fudan University Shanghai 200433 China
| | - Ran Liu
- State Key Laboratory of ASIC & System, School of Information Science and Technology, Fudan University Shanghai 200433 China
| | - Weihuang Yang
- Engineering Research Center of Smart Microsensors and Microsystems, Ministry of Education, College of Electronics and Information, Hangzhou Dianzi University Hangzhou 310018 China
| | - Zhi-Jun Qiu
- State Key Laboratory of ASIC & System, School of Information Science and Technology, Fudan University Shanghai 200433 China
| | - Chunxiao Cong
- State Key Laboratory of ASIC & System, School of Information Science and Technology, Fudan University Shanghai 200433 China
- Yiwu Research Institute of Fudan University Chengbei Road Yiwu City 322000 Zhejiang China
| |
Collapse
|
30
|
Faria Junior PE, Fabian J. Signatures of Electric Field and Layer Separation Effects on the Spin-Valley Physics of MoSe 2/WSe 2 Heterobilayers: From Energy Bands to Dipolar Excitons. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:1187. [PMID: 37049281 PMCID: PMC10096971 DOI: 10.3390/nano13071187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/22/2023] [Accepted: 03/24/2023] [Indexed: 06/19/2023]
Abstract
Multilayered van der Waals heterostructures based on transition metal dichalcogenides are suitable platforms on which to study interlayer (dipolar) excitons, in which electrons and holes are localized in different layers. Interestingly, these excitonic complexes exhibit pronounced valley Zeeman signatures, but how their spin-valley physics can be further altered due to external parameters-such as electric field and interlayer separation-remains largely unexplored. Here, we perform a systematic analysis of the spin-valley physics in MoSe2/WSe2 heterobilayers under the influence of an external electric field and changes of the interlayer separation. In particular, we analyze the spin (Sz) and orbital (Lz) degrees of freedom, and the symmetry properties of the relevant band edges (at K, Q, and Γ points) of high-symmetry stackings at 0° (R-type) and 60° (H-type) angles-the important building blocks present in moiré or atomically reconstructed structures. We reveal distinct hybridization signatures on the spin and the orbital degrees of freedom of low-energy bands, due to the wave function mixing between the layers, which are stacking-dependent, and can be further modified by electric field and interlayer distance variation. We find that H-type stackings favor large changes in the g-factors as a function of the electric field, e.g., from -5 to 3 in the valence bands of the Hhh stacking, because of the opposite orientation of Sz and Lz of the individual monolayers. For the low-energy dipolar excitons (direct and indirect in k-space), we quantify the electric dipole moments and polarizabilities, reflecting the layer delocalization of the constituent bands. Furthermore, our results show that direct dipolar excitons carry a robust valley Zeeman effect nearly independent of the electric field, but tunable by the interlayer distance, which can be rendered experimentally accessible via applied external pressure. For the momentum-indirect dipolar excitons, our symmetry analysis indicates that phonon-mediated optical processes can easily take place. In particular, for the indirect excitons with conduction bands at the Q point for H-type stackings, we find marked variations of the valley Zeeman (∼4) as a function of the electric field, which notably stands out from the other dipolar exciton species. Our analysis suggests that stronger signatures of the coupled spin-valley physics are favored in H-type stackings, which can be experimentally investigated in samples with twist angle close to 60°. In summary, our study provides fundamental microscopic insights into the spin-valley physics of van der Waals heterostructures, which are relevant to understanding the valley Zeeman splitting of dipolar excitonic complexes, and also intralayer excitons.
Collapse
Affiliation(s)
- Paulo E. Faria Junior
- Institute for Theoretical Physics, University of Regensburg, 93040 Regensburg, Germany
| | | |
Collapse
|
31
|
Elbanna A, Jiang H, Fu Q, Zhu JF, Liu Y, Zhao M, Liu D, Lai S, Chua XW, Pan J, Shen ZX, Wu L, Liu Z, Qiu CW, Teng J. 2D Material Infrared Photonics and Plasmonics. ACS NANO 2023; 17:4134-4179. [PMID: 36821785 DOI: 10.1021/acsnano.2c10705] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Two-dimensional (2D) materials including graphene, transition metal dichalcogenides, black phosphorus, MXenes, and semimetals have attracted extensive and widespread interest over the past years for their many intriguing properties and phenomena, underlying physics, and great potential for applications. The vast library of 2D materials and their heterostructures provides a diverse range of electrical, photonic, mechanical, and chemical properties with boundless opportunities for photonics and plasmonic devices. The infrared (IR) regime, with wavelengths across 0.78 μm to 1000 μm, has particular technological significance in industrial, military, commercial, and medical settings while facing challenges especially in the limit of materials. Here, we present a comprehensive review of the varied approaches taken to leverage the properties of the 2D materials for IR applications in photodetection and sensing, light emission and modulation, surface plasmon and phonon polaritons, non-linear optics, and Smith-Purcell radiation, among others. The strategies examined include the growth and processing of 2D materials, the use of various 2D materials like semiconductors, semimetals, Weyl-semimetals and 2D heterostructures or mixed-dimensional hybrid structures, and the engineering of light-matter interactions through nanophotonics, metasurfaces, and 2D polaritons. Finally, we give an outlook on the challenges in realizing high-performance and ambient-stable devices and the prospects for future research and large-scale commercial applications.
Collapse
Affiliation(s)
- Ahmed Elbanna
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Singapore 138634, Singapore
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 50 Nanyang Avenue, Singapore 637371, Singapore
| | - Hao Jiang
- Department of Electrical and Electronic Engineering, National University of Singapore, Singapore 117583, Singapore
| | - Qundong Fu
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
- CINTRA CNRS/NTU/THALES, UMI 3288, Research Techno Plaza, Singapore 637553, Singapore
| | - Juan-Feng Zhu
- Science, Mathematics and Technology (SMT), Singapore University of Technology and Design, 8 Somapah Road, Singapore 487372, Singapore
| | - Yuanda Liu
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Singapore 138634, Singapore
| | - Meng Zhao
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Singapore 138634, Singapore
| | - Dongjue Liu
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Samuel Lai
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Singapore 138634, Singapore
| | - Xian Wei Chua
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Singapore 138634, Singapore
| | - Jisheng Pan
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Singapore 138634, Singapore
| | - Ze Xiang Shen
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 50 Nanyang Avenue, Singapore 637371, Singapore
- Interdisciplinary Graduate Program, Energy Research Institute@NTU, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
- The Photonics Institute and Center for Disruptive Photonic Technologies, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 Singapore
| | - Lin Wu
- Science, Mathematics and Technology (SMT), Singapore University of Technology and Design, 8 Somapah Road, Singapore 487372, Singapore
- Institute of High Performance Computing, Agency for Science Technology and Research (A*STAR), 1 Fusionopolis Way, Singapore 138632, Singapore
| | - Zheng Liu
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
- CINTRA CNRS/NTU/THALES, UMI 3288, Research Techno Plaza, Singapore 637553, Singapore
| | - Cheng-Wei Qiu
- Department of Electrical and Electronic Engineering, National University of Singapore, Singapore 117583, Singapore
| | - Jinghua Teng
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Singapore 138634, Singapore
| |
Collapse
|
32
|
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: 8] [Impact Index Per Article: 8.0] [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.
Collapse
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.
| |
Collapse
|
33
|
Yoon Y, Zhang Z, Qi R, Joe AY, Sailus R, Watanabe K, Taniguchi T, Tongay S, Wang F. Charge Transfer Dynamics in MoSe 2/hBN/WSe 2 Heterostructures. NANO LETTERS 2022; 22:10140-10146. [PMID: 36485010 DOI: 10.1021/acs.nanolett.2c04030] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Ultrafast charge transfer processes provide a facile way to create interlayer excitons in directly contacted transition metal dichalcogenide (TMD) layers. More sophisticated heterostructures composed of TMD/hBN/TMD enable new ways to control interlayer exciton properties and achieve novel exciton phenomena, such as exciton insulators and condensates, where longer lifetimes are desired. In this work, we experimentally study the charge transfer dynamics in a heterostructure composed of a 1 nm thick hBN spacer between MoSe2 and WSe2 monolayers. We observe the hole transfer from MoSe2 to WSe2 through the hBN barrier with a time constant of 500 ps, which is over 3 orders of magnitude slower than that between TMD layers without a spacer. Furthermore, we observe strong competition between the interlayer charge transfer and intralayer exciton-exciton annihilation processes at high excitation densities. Our work opens possibilities to understand charge transfer pathways in TMD/hBN/TMD heterostructures for the efficient generation and control of interlayer excitons.
Collapse
Affiliation(s)
- Yoseob Yoon
- Department of Physics, University of California, Berkeley, California94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California94720, United States
| | - Zuocheng Zhang
- Department of Physics, University of California, Berkeley, California94720, United States
| | - Ruishi Qi
- Department of Physics, University of California, Berkeley, California94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California94720, United States
| | - Andrew Y Joe
- Department of Physics, University of California, Berkeley, California94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California94720, United States
| | - Renee Sailus
- School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona85287, United States
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba305-0044, Japan
| | - Sefaattin Tongay
- School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona85287, United States
| | - Feng Wang
- Department of Physics, University of California, Berkeley, California94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California94720, United States
| |
Collapse
|
34
|
Susarla S, Naik MH, Blach DD, Zipfel J, Taniguchi T, Watanabe K, Huang L, Ramesh R, da Jornada FH, Louie SG, Ercius P, Raja A. Hyperspectral imaging of exciton confinement within a moiré unit cell with a subnanometer electron probe. Science 2022; 378:1235-1239. [PMID: 36520893 DOI: 10.1126/science.add9294] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Electronic and optical excitations in two-dimensional systems are distinctly sensitive to the presence of a moiré superlattice. We used cryogenic transmission electron microscopy and spectroscopy to simultaneously image the structural reconstruction and associated localization of the lowest-energy intralayer exciton in a rotationally aligned WS2-WSe2 moiré superlattice. In conjunction with optical spectroscopy and ab initio calculations, we determined that the exciton center-of-mass wave function is confined to a radius of approximately 2 nanometers around the highest-energy stacking site in the moiré unit cell. Our results provide direct evidence that atomic reconstructions lead to the strongly confining moiré potentials and that engineering strain at the nanoscale will enable new types of excitonic lattices.
Collapse
Affiliation(s)
- Sandhya Susarla
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.,Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Mit H Naik
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.,Department of Physics, University of California, Berkeley, CA 94720, USA
| | - Daria D Blach
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA
| | - Jonas Zipfel
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - 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
| | - Libai Huang
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA
| | - Ramamoorthy Ramesh
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.,Department of Physics, University of California, Berkeley, CA 94720, USA.,Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA
| | - Felipe H da Jornada
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA.,Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Steven G Louie
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.,Department of Physics, University of California, Berkeley, CA 94720, USA
| | - Peter Ercius
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Archana Raja
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| |
Collapse
|
35
|
Zheng W, Xiang L, de Quesada FA, Augustin M, Lu Z, Wilson M, Sood A, Wu F, Shcherbakov D, Memaran S, Baumbach RE, McCandless GT, Chan JY, Liu S, Edgar JH, Lau CN, Lui CH, Santos EJG, Lindenberg A, Smirnov D, Balicas L. Thickness- and Twist-Angle-Dependent Interlayer Excitons in Metal Monochalcogenide Heterostructures. ACS NANO 2022; 16:18695-18707. [PMID: 36257051 DOI: 10.1021/acsnano.2c07394] [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
Interlayer excitons, or bound electron-hole pairs whose constituent quasiparticles are located in distinct stacked semiconducting layers, are being intensively studied in heterobilayers of two-dimensional semiconductors. They owe their existence to an intrinsic type-II band alignment between both layers that convert these into p-n junctions. Here, we unveil a pronounced interlayer exciton (IX) in heterobilayers of metal monochalcogenides, namely, γ-InSe on ε-GaSe, whose pronounced emission is adjustable just by varying their thicknesses given their number of layers dependent direct band gaps. Time-dependent photoluminescense spectroscopy unveils considerably longer interlayer exciton lifetimes with respect to intralayer ones, thus confirming their nature. The linear Stark effect yields a bound electron-hole pair whose separation d is just (3.6 ± 0.1) Å with d being very close to dSe = 3.4 Å which is the calculated interfacial Se separation. The envelope of IX is twist-angle-dependent and describable by superimposed emissions that are nearly equally spaced in energy, as if quantized due to localization induced by the small moiré periodicity. These heterostacks are characterized by extremely flat interfacial valence bands making them prime candidates for the observation of magnetism or other correlated electronic phases upon carrier doping.
Collapse
Affiliation(s)
- Wenkai Zheng
- National High Magnetic Field Laboratory, Tallahassee, Florida32310, United States
- Department of Physics, Florida State University, Tallahassee, Florida32306, United States
| | - Li Xiang
- National High Magnetic Field Laboratory, Tallahassee, Florida32310, United States
- Department of Physics, Florida State University, Tallahassee, Florida32306, United States
| | - Felipe A de Quesada
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California94025, United States
- Department of Materials Science and Engineering, Stanford University, Stanford, California94305, United States
| | - Mathias Augustin
- Institute for Condensed Matter Physics and Complex Systems, School of Physics and Astronomy, The University of Edinburgh, EdinburghEH9 3FD, United Kingdom
- Higgs Centre for Theoretical Physics, The University of Edinburgh, EdinburghEH9 3FD, United Kingdom
| | - Zhengguang Lu
- National High Magnetic Field Laboratory, Tallahassee, Florida32310, United States
- Department of Physics, Florida State University, Tallahassee, Florida32306, United States
| | - Matthew Wilson
- Department of Physics and Astronomy, University of California, Riverside, California92521, United States
| | - Aditya Sood
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California94025, United States
- Department of Materials Science and Engineering, Stanford University, Stanford, California94305, United States
| | - Fengcheng Wu
- School of Physics and Technology, Wuhan University, Wuhan, 430072China
| | - Dmitry Shcherbakov
- Department of Physics, The Ohio State University, Columbus, Ohio43210, United States
| | - Shahriar Memaran
- National High Magnetic Field Laboratory, Tallahassee, Florida32310, United States
- Department of Physics, Florida State University, Tallahassee, Florida32306, United States
| | - Ryan E Baumbach
- National High Magnetic Field Laboratory, Tallahassee, Florida32310, United States
- Department of Physics, Florida State University, Tallahassee, Florida32306, United States
| | - Gregory T McCandless
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas76798, United States
| | - Julia Y Chan
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas76798, United States
| | - Song Liu
- Tim Taylor Department of Chemical Engineering, Kansas State University, Manhattan, Kansas66506, United States
| | - James H Edgar
- Tim Taylor Department of Chemical Engineering, Kansas State University, Manhattan, Kansas66506, United States
| | - Chun Ning Lau
- Department of Physics, The Ohio State University, Columbus, Ohio43210, United States
| | - Chun Hung Lui
- Department of Physics and Astronomy, University of California, Riverside, California92521, United States
| | - Elton J G Santos
- Institute for Condensed Matter Physics and Complex Systems, School of Physics and Astronomy, The University of Edinburgh, EdinburghEH9 3FD, United Kingdom
- Higgs Centre for Theoretical Physics, The University of Edinburgh, EdinburghEH9 3FD, United Kingdom
- Donostia International Physics Centre, 20018Donostia-San Sebastian, Spain
| | - Aaron Lindenberg
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California94025, United States
- Department of Materials Science and Engineering, Stanford University, Stanford, California94305, United States
| | - Dmitry Smirnov
- National High Magnetic Field Laboratory, Tallahassee, Florida32310, United States
| | - Luis Balicas
- National High Magnetic Field Laboratory, Tallahassee, Florida32310, United States
- Department of Physics, Florida State University, Tallahassee, Florida32306, United States
| |
Collapse
|
36
|
Li S, Zheng H, Wu B, Ding J, He J, Liu Z, Liu Y. Layer-dependent excitonic valley polarization properties in MoS 2-WS 2 heterostructures. OPTICS LETTERS 2022; 47:5861-5864. [PMID: 37219121 DOI: 10.1364/ol.474799] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 10/13/2022] [Indexed: 05/24/2023]
Abstract
In this work, we investigate the polarization of the excitonics valley in MoS2-WS2 heterostructures using circular polarization-resolved photoluminescence. The valley polarization is the largest (≈28.45%) in the 1L-1L MoS2-WS2 heterostructure and the polarizability of AWS2 decreases as the number of WS2 layers increases. We further observed a redshift of exciton XMoS2- in MoS2-WS2 heterostructures with the increase of WS2 layers, which is attributed to the displacement of the MoS2 band edge, indicating the layer-sensitive optical properties of the MoS2-WS2 heterostructure. Our findings shed light on the understanding of exciton behavior in multilayer MoS2-WS2 heterostructures that may promote their potential applications in optoelectronic devices.
Collapse
|
37
|
Sigger F, Amersdorffer I, Hötger A, Nutz M, Kiemle J, Taniguchi T, Watanabe K, Förg M, Noe J, Finley JJ, Högele A, Holleitner AW, Hümmer T, Hunger D, Kastl C. Ultra-Sensitive Extinction Measurements of Optically Active Defects in Monolayer MoS 2. J Phys Chem Lett 2022; 13:10291-10296. [PMID: 36305703 DOI: 10.1021/acs.jpclett.2c02386] [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 utilize cavity-enhanced extinction spectroscopy to directly quantify the optical absorption of defects in MoS2 generated by helium ion bombardment. We achieve hyperspectral imaging of specific defect patterns with a detection limit below 0.01% extinction, corresponding to a detectable defect density below 1 × 1011 cm-2. The corresponding spectra reveal a broad subgap absorption, being consistent with theoretical predictions related to sulfur vacancy-bound excitons in MoS2. Our results highlight cavity-enhanced extinction spectroscopy as efficient means for the detection of optical transitions in nanoscale thin films with weak absorption, applicable to a broad range of materials.
Collapse
Affiliation(s)
- Florian Sigger
- Walter Schottky Institute and Physics Department, Technical University of Munich, Am Coulombwall 4a, 85748Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), Schellingstr. 4, 80799Munich, Germany
| | - Ines Amersdorffer
- Munich Center for Quantum Science and Technology (MCQST), Schellingstr. 4, 80799Munich, Germany
- Qlibri GmbH, Maistr. 67, 80337Munich, Germany
- Faculty of Physics, Ludwig-Maximilians-Universität München, Schellingstraße 4, 80799Munich, Germany
| | - Alexander Hötger
- Walter Schottky Institute and Physics Department, Technical University of Munich, Am Coulombwall 4a, 85748Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), Schellingstr. 4, 80799Munich, Germany
| | - Manuel Nutz
- Munich Center for Quantum Science and Technology (MCQST), Schellingstr. 4, 80799Munich, Germany
- Qlibri GmbH, Maistr. 67, 80337Munich, Germany
- Faculty of Physics, Ludwig-Maximilians-Universität München, Schellingstraße 4, 80799Munich, Germany
| | - Jonas Kiemle
- Walter Schottky Institute and Physics Department, Technical University of Munich, Am Coulombwall 4a, 85748Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), Schellingstr. 4, 80799Munich, Germany
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba 305-0044, Japan
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba305-0044, Japan
| | - Michael Förg
- Munich Center for Quantum Science and Technology (MCQST), Schellingstr. 4, 80799Munich, Germany
- Qlibri GmbH, Maistr. 67, 80337Munich, Germany
- Faculty of Physics, Ludwig-Maximilians-Universität München, Schellingstraße 4, 80799Munich, Germany
| | - Jonathan Noe
- Munich Center for Quantum Science and Technology (MCQST), Schellingstr. 4, 80799Munich, Germany
- Qlibri GmbH, Maistr. 67, 80337Munich, Germany
- Faculty of Physics, Ludwig-Maximilians-Universität München, Schellingstraße 4, 80799Munich, Germany
| | - Jonathan J Finley
- Walter Schottky Institute and Physics Department, Technical University of Munich, Am Coulombwall 4a, 85748Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), Schellingstr. 4, 80799Munich, Germany
| | - Alexander Högele
- Munich Center for Quantum Science and Technology (MCQST), Schellingstr. 4, 80799Munich, Germany
- Faculty of Physics, Ludwig-Maximilians-Universität München, Schellingstraße 4, 80799Munich, Germany
| | - Alexander W Holleitner
- Walter Schottky Institute and Physics Department, Technical University of Munich, Am Coulombwall 4a, 85748Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), Schellingstr. 4, 80799Munich, Germany
| | - Thomas Hümmer
- Munich Center for Quantum Science and Technology (MCQST), Schellingstr. 4, 80799Munich, Germany
- Qlibri GmbH, Maistr. 67, 80337Munich, Germany
- Faculty of Physics, Ludwig-Maximilians-Universität München, Schellingstraße 4, 80799Munich, Germany
| | - David Hunger
- Physikalisches Institut, Karlsruhe Institute of Technology, Wolfgang-Gaede-Str. 1, 76131Karlsruhe, Germany
| | - Christoph Kastl
- Walter Schottky Institute and Physics Department, Technical University of Munich, Am Coulombwall 4a, 85748Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), Schellingstr. 4, 80799Munich, Germany
| |
Collapse
|
38
|
Guo Z, Gu H, Fang M, Ye L, Liu S. Giant in-plane optical and electronic anisotropy of tellurene: a quantitative exploration. NANOSCALE 2022; 14:12238-12246. [PMID: 35929846 DOI: 10.1039/d2nr03226k] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Tellurene's giant in-plane optical anisotropy brings richer physics and an extra degree of freedom to regulate its optical properties for designing novel and unique polarization-sensitive devices. Here, we quantitatively evaluate the in-plane optical anisotropy of tellurene and further reveal its physical origins by combining imaging Mueller matrix spectroscopic ellipsometry (MMSE) and first-principles calculations. The anisotropic complex refractive indices and dielectric functions, as well as the derived giant birefringence (|Δn|max = 0.48) and dichroism (Δk > 0.4), are accurately determined by imaging MMSE to quantitatively evaluate the in-plane optical anisotropy of tellurene. With density functional theory (DFT), tellurene's optical anisotropy is connected to its low-symmetry lattice structure with electrical anisotropy (including the anisotropic effective mass, partial charge density, and carrier mobility), leading to anisotropic electric polarization and ultimately optical anisotropy. This work provides a general and quantitative way to explore the optical anisotropy and also helps to comprehend the connection between the lattice structure and the optical anisotropy of tellurene and even other emerging low-symmetry materials, which will further promote their polarization-sensitive optical applications.
Collapse
Affiliation(s)
- Zhengfeng Guo
- State Key Laboratory of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan 430074, China.
- Innovation Institute, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Honggang Gu
- State Key Laboratory of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan 430074, China.
- Optics Valley Laboratory, Wuhan 430074, China
| | - Mingsheng Fang
- State Key Laboratory of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan 430074, China.
| | - Lei Ye
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Shiyuan Liu
- State Key Laboratory of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan 430074, China.
- Optics Valley Laboratory, Wuhan 430074, China
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China
| |
Collapse
|
39
|
Electrically tunable two-dimensional heterojunctions for miniaturized near-infrared spectrometers. Nat Commun 2022; 13:4627. [PMID: 35941126 PMCID: PMC9360404 DOI: 10.1038/s41467-022-32306-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 07/25/2022] [Indexed: 11/20/2022] Open
Abstract
Miniaturized spectrometers are of considerable interest for their portability. Most designs to date employ a photodetector array with distinct spectral responses or require elaborated integration of micro & nano optic modules, typically with a centimeter-scale footprint. Here, we report a design of a micron-sized near-infrared ultra-miniaturized spectrometer based on two-dimensional van der Waals heterostructure (2D-vdWH). By introducing heavy metal atoms with delocalized electronic orbitals between 2D-vdWHs, we greatly enhance the interlayer coupling and realize electrically tunable infrared photoresponse (1.15 to 1.47 μm). Combining the gate-tunable photoresponse and regression algorithm, we achieve spectral reconstruction and spectral imaging in a device with an active footprint < 10 μm. Considering the ultra-small footprint and simple fabrication process, the 2D-vdWHs with designable bandgap energy and enhanced photoresponse offer an attractive solution for on-chip infrared spectroscopy. Miniaturized infrared spectrometers are required for imaging and remote sensing applications, but they are usually characterized by a cm-scale footprint. Here, the authors report the realization of near-infrared spectrometers based on Au-atom-intercalated ReS2/WSe2 heterostructures with an active footprint < 10 μm and electrically tunable photoresponse.
Collapse
|