1
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Wang Z, Kalathingal V, Trushin M, Liu J, Wang J, Guo Y, Özyilmaz B, Nijhuis CA, Eda G. Upconversion electroluminescence in 2D semiconductors integrated with plasmonic tunnel junctions. NATURE NANOTECHNOLOGY 2024; 19:993-999. [PMID: 38641642 DOI: 10.1038/s41565-024-01650-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 03/13/2024] [Indexed: 04/21/2024]
Abstract
Plasmonic tunnel junctions are a unique electroluminescent system in which light emission occurs via an interplay between tunnelling electrons and plasmonic fields instead of electron-hole recombination as in conventional light-emitting diodes. It was previously shown that placing luminescent molecules in the tunneling pathway of nanoscopic tunnel junctions results in peculiar upconversion electroluminescence where the energy of emitted photons exceeds that of excitation electrons. Here we report the observation of upconversion electroluminescence in macroscopic van der Waals plasmonic tunnel junctions comprising gold and few-layer graphene electrodes separated by a ~2-nm-thick hexagonal boron nitride tunnel barrier and a monolayer semiconductor. We find that the semiconductor ground exciton emission is triggered at excitation electron energies lower than the semiconductor optical gap. Interestingly, this upconversion is reached in devices operating at a low conductance (<10-6 S) and low power density regime (<102 W cm-2), defying explanation through existing proposed mechanisms. By examining the scaling relationship between plasmonic and excitonic emission intensities, we elucidate the role of inelastic electron tunnelling dipoles that induce optically forbidden transitions in the few-layer graphene electrode and ultrafast hot carrier transfer across the van der Waals interface.
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Affiliation(s)
- Zhe Wang
- Department of Chemistry, National University of Singapore, Singapore, Singapore
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Vijith Kalathingal
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
- Department of Physics, Kannur University, Swami Anandatheertha Campus-Payyanur, Kannur, India
| | - Maxim Trushin
- Institute for Functional Intelligent Materials, National University of Singapore, Singapore, Singapore
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, Singapore
- Department of Material Science and Engineering, National University of Singapore, Singapore, Singapore
| | - Jiawei Liu
- Institute for Functional Intelligent Materials, National University of Singapore, Singapore, Singapore
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, Singapore
- Department of Physics, National University of Singapore, Singapore, Singapore
| | - Junyong Wang
- CAS Key Laboratory of Nano-Bio Interface and Key Laboratory of Nanodevices and Applications, i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, China
| | - Yongxin Guo
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Barbaros Özyilmaz
- Institute for Functional Intelligent Materials, National University of Singapore, Singapore, Singapore
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, Singapore
- Department of Material Science and Engineering, National University of Singapore, Singapore, Singapore
- Department of Physics, National University of Singapore, Singapore, Singapore
| | - Christian A Nijhuis
- Hybrid Materials for Opto-Electronics Group, Department of Molecules and Materials, MESA+ Institute for Nanotechnology, Molecules Center and Center for Brain-Inspired Nano Systems, Faculty of Science and Technology, University of Twente, Enschede, the Netherlands.
| | - Goki Eda
- Department of Chemistry, National University of Singapore, Singapore, Singapore.
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, Singapore.
- Department of Physics, National University of Singapore, Singapore, Singapore.
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2
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Di Giulio V, Akerboom E, Polman A, García de Abajo FJ. Toward Optimum Coupling between Free Electrons and Confined Optical Modes. ACS NANO 2024; 18:14255-14275. [PMID: 38775711 PMCID: PMC11155252 DOI: 10.1021/acsnano.3c12977] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 04/10/2024] [Accepted: 04/25/2024] [Indexed: 06/05/2024]
Abstract
Free electrons are excellent tools to probe and manipulate nanoscale optical fields with emerging applications in ultrafast spectromicroscopy and quantum metrology. However, advances in this field are hindered by the small probability associated with the excitation of single optical modes by individual free electrons. Here, we theoretically investigate the scaling properties of the electron-driven excitation probability for a wide variety of optical modes including plasmons in metallic nanostructures and Mie resonances in dielectric cavities, spanning a broad spectral range that extends from the ultraviolet to the infrared region. The highest probabilities for the direct generation of three-dimensionally confined modes are observed at low electron and mode energies in small structures, with order-unity (∼100%) coupling demanding the use of <100 eV electrons interacting with eV polaritons confined down to tens of nanometers in space. Electronic transitions in artificial atoms also emerge as practical systems to realize strong coupling to few-eV free electrons. In contrast, conventional dielectric cavities reach a maximum probability in the few-percent range. In addition, we show that waveguide modes can be generated with higher-than-unity efficiency by phase-matched interaction with grazing electrons, suggesting a practical method to create multiple excitations of a localized optical mode by an individual electron through funneling the so-generated propagating photons into a confining cavity─an alternative approach to direct electron-cavity interaction. Our work provides a roadmap to optimize electron-photon coupling with potential applications in electron spectromicroscopy as well as nonlinear and quantum optics at the nanoscale.
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Affiliation(s)
- Valerio Di Giulio
- The
Barcelona Institute of Science and Technology, Institut de Ciencies Fotoniques-ICFO, 08860 Castelldefels (Barcelona), Spain
| | - Evelijn Akerboom
- Center
for Nanophotonics, NWO-Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
| | - Albert Polman
- Center
for Nanophotonics, NWO-Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
| | - F. Javier García de Abajo
- The
Barcelona Institute of Science and Technology, Institut de Ciencies Fotoniques-ICFO, 08860 Castelldefels (Barcelona), Spain
- ICREA-Institució
Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Spain
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3
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Thomas JC, Chen W, Xiong Y, Barker BA, Zhou J, Chen W, Rossi A, Kelly N, Yu Z, Zhou D, Kumari S, Barnard ES, Robinson JA, Terrones M, Schwartzberg A, Ogletree DF, Rotenberg E, Noack MM, Griffin S, Raja A, Strubbe DA, Rignanese GM, Weber-Bargioni A, Hautier G. A substitutional quantum defect in WS 2 discovered by high-throughput computational screening and fabricated by site-selective STM manipulation. Nat Commun 2024; 15:3556. [PMID: 38670956 DOI: 10.1038/s41467-024-47876-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 04/15/2024] [Indexed: 04/28/2024] Open
Abstract
Point defects in two-dimensional materials are of key interest for quantum information science. However, the parameter space of possible defects is immense, making the identification of high-performance quantum defects very challenging. Here, we perform high-throughput (HT) first-principles computational screening to search for promising quantum defects within WS2, which present localized levels in the band gap that can lead to bright optical transitions in the visible or telecom regime. Our computed database spans more than 700 charged defects formed through substitution on the tungsten or sulfur site. We found that sulfur substitutions enable the most promising quantum defects. We computationally identify the neutral cobalt substitution to sulfur (CoS 0 ) and fabricate it with scanning tunneling microscopy (STM). The CoS 0 electronic structure measured by STM agrees with first principles and showcases an attractive quantum defect. Our work shows how HT computational screening and nanoscale synthesis routes can be combined to design promising quantum defects.
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Affiliation(s)
- John C Thomas
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA.
| | - Wei Chen
- Institute of Condensed Matter and Nanoscicence, Université Catholique de Louvain, Louvain-la-Neuve, 1348, Belgium
| | - Yihuang Xiong
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
| | - Bradford A Barker
- Department of Physics, University of California, Merced, Merced, CA, 95343, USA
| | - Junze Zhou
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Weiru Chen
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
| | - Antonio Rossi
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Nolan Kelly
- Department of Physics, University of California, Merced, Merced, CA, 95343, USA
| | - Zhuohang Yu
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, 16082, USA
- Center for Two-Dimensional and Layered Materials, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Da Zhou
- Department of Physics, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Shalini Kumari
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, 16082, USA
- Center for Two-Dimensional and Layered Materials, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Edward S Barnard
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Joshua A Robinson
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, 16082, USA
- Center for Two-Dimensional and Layered Materials, The Pennsylvania State University, University Park, PA, 16802, USA
- Department of Physics, The Pennsylvania State University, University Park, PA, 16802, USA
- Department of Chemistry, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Mauricio Terrones
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, 16082, USA
- Center for Two-Dimensional and Layered Materials, The Pennsylvania State University, University Park, PA, 16802, USA
- Department of Physics, The Pennsylvania State University, University Park, PA, 16802, USA
- Department of Chemistry, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Adam Schwartzberg
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - D Frank Ogletree
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Eli Rotenberg
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Marcus M Noack
- Applied Mathematics and Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Sinéad Griffin
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Archana Raja
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - David A Strubbe
- Department of Physics, University of California, Merced, Merced, CA, 95343, USA
| | - Gian-Marco Rignanese
- Institute of Condensed Matter and Nanoscicence, Université Catholique de Louvain, Louvain-la-Neuve, 1348, Belgium
| | - Alexander Weber-Bargioni
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Geoffroy Hautier
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA.
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4
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Geng H, Tang J, Wu Y, Yu Y, Guest JR, Zhang R. Imaging Valley Excitons in a 2D Semiconductor with Scanning Tunneling Microscope-Induced Luminescence. ACS NANO 2024; 18:8961-8970. [PMID: 38470346 DOI: 10.1021/acsnano.3c12555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
Valley excitons dominate the optoelectronic response of transition-metal dichalcogenides and are drastically affected by structural and environmental inhomogeneities localized in these materials. Critical to understanding and controlling these nanoscale excitonic changes is the ability to correlate the imaging of excitonic states with crystalline structures on the atomic scale. Here, we apply scanning tunneling microscope-induced luminescence microscopy to image valley excitons in a semiconducting transition-metal dichalcogenide monolayer decoupled by a 10 nanometer-thick hexagonal-boron-nitride flake incorporated in a lateral homojunction on an Au electrode surface. This design enables the observation of chiral excitonic emission arising from neutral and charged valley excitons of the monolayer semiconductor at ambipolar voltages with a quantum efficiency up to ∼10-5 photon/electron. The measured light helicity demonstrates considerable circular polarization dependent on the sample voltage, reaching as much as 40%. The real-space luminescence imaging maps─at subnanometer resolution─of the valley excitons reveal striking spatial variations associated with localized inhomogeneities, including surface impurities and possibly nanoscale dielectric and/or potential disorders in the monolayer. Our study introduces a promising format for 2D materials to explore and tailor their optoelectronic processes at the atomic scale.
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Affiliation(s)
- Hairui Geng
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Key Laboratory of Optoelectronic Information Acquisition and Manipulation, Ministry of Education, School of Physics and Optoelectronics Engineering, Anhui University, Hefei Anhui 230601, China
| | - Jie Tang
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Key Laboratory of Optoelectronic Information Acquisition and Manipulation, Ministry of Education, School of Physics and Optoelectronics Engineering, Anhui University, Hefei Anhui 230601, China
| | - Yanwei Wu
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Key Laboratory of Optoelectronic Information Acquisition and Manipulation, Ministry of Education, School of Physics and Optoelectronics Engineering, Anhui University, Hefei Anhui 230601, China
| | - Yuanqin Yu
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Key Laboratory of Optoelectronic Information Acquisition and Manipulation, Ministry of Education, School of Physics and Optoelectronics Engineering, Anhui University, Hefei Anhui 230601, China
| | - Jeffrey R Guest
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Rui Zhang
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Key Laboratory of Optoelectronic Information Acquisition and Manipulation, Ministry of Education, School of Physics and Optoelectronics Engineering, Anhui University, Hefei Anhui 230601, China
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5
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Aliyar T, Ma H, Krishnan R, Singh G, Chong BQ, Wang Y, Verzhbitskiy I, Yu Wong CP, Johnson Goh KE, Shen ZX, Koh TS, Rahman R, Weber B. Symmetry Breaking and Spin-Orbit Coupling for Individual Vacancy-Induced In-Gap States in MoS 2 Monolayers. NANO LETTERS 2024; 24:2142-2148. [PMID: 38323571 DOI: 10.1021/acs.nanolett.3c03681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2024]
Abstract
Spins confined to point defects in atomically thin semiconductors constitute well-defined atomic-scale quantum systems that are being explored as single-photon emitters and spin qubits. Here, we investigate the in-gap electronic structure of individual sulfur vacancies in molybdenum disulfide (MoS2) monolayers using resonant tunneling scanning probe spectroscopy in the Coulomb blockade regime. Spectroscopic mapping of defect wave functions reveals an interplay of local symmetry breaking by a charge-state-dependent Jahn-Teller lattice distortion that, when combined with strong (≃100 meV) spin-orbit coupling, leads to a locking of an unpaired spin-1/2 magnetic moment to the lattice at low temperature, susceptible to lattice strain. Our results provide new insights into the spin and electronic structure of vacancy-induced in-gap states toward their application as electrically and optically addressable quantum systems.
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Affiliation(s)
- Thasneem Aliyar
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Hongyang Ma
- School of Physics, University of New South Wales, Sydney, NSW 2052, Australia
| | - Radha Krishnan
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Gagandeep Singh
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Bi Qi Chong
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Yitao Wang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Ivan Verzhbitskiy
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), Singapore 138634, Singapore
| | - Calvin Pei Yu Wong
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), Singapore 138634, Singapore
| | - Kuan Eng Johnson Goh
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), Singapore 138634, Singapore
| | - Ze Xiang Shen
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Teck Seng Koh
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Rajib Rahman
- School of Physics, University of New South Wales, Sydney, NSW 2052, Australia
| | - Bent Weber
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
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6
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Lodge MS, Marcellina E, Zhu Z, Li XP, Kaczorowski D, Fuhrer MS, Yang SA, Weber B. Symmetry-selective quasiparticle scattering and electric field tunability of the ZrSiS surface electronic structure. NANOTECHNOLOGY 2024; 35:195704. [PMID: 38316053 DOI: 10.1088/1361-6528/ad2639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 02/05/2024] [Indexed: 02/07/2024]
Abstract
Three-dimensional Dirac semimetals with square-net non-symmorphic symmetry, such as ternary ZrXY (X = Si, Ge; Y = S, Se, Te) compounds, have attracted significant attention owing to the presence of topological nodal lines, loops, or networks in their bulk. Orbital symmetry plays a profound role in such materials as the different branches of the nodal dispersion can be distinguished by their distinct orbital symmetry eigenvalues. The presence of different eigenvalues suggests that scattering between states of different orbital symmetry may be strongly suppressed. Indeed, in ZrSiS, there has been no clear experimental evidence of quasiparticle scattering reported between states of different symmetry eigenvalues at small wave vectorq⃗.Here we show, using quasiparticle interference, that atomic step-edges in the ZrSiS surface facilitate quasiparticle scattering between states of different symmetry eigenvalues. This symmetry eigenvalue mixing quasiparticle scattering is the first to be reported for ZrSiS and contrasts quasiparticle scattering with no mixing of symmetry eigenvalues, where the latter occurs with scatterers preserving the glide mirror symmetry of the crystal lattice, e.g. native point defects in ZrSiS. Finally, we show that the electronic structure of the ZrSiS surface, including its unique floating band surface state, can be tuned by a vertical electric field locally applied by the tip of a scanning tunneling microscope (STM), enabling control of a spin-orbit induced avoided crossing near the Fermi level by as much as 300%.
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Affiliation(s)
- Michael S Lodge
- School of Physical and Mathematical Sciences, Nanyang Technological University, 637371, Singapore
- Department of Physics, University of Central Florida, Orlando, FL 32816, United States of America
- NanoScience Technology Center, University of Central Florida, Orlando, FL 32826, United States of America
| | - Elizabeth Marcellina
- School of Physical and Mathematical Sciences, Nanyang Technological University, 637371, Singapore
| | - Ziming Zhu
- Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education, Department of Physics and Synergetic Innovation Center for Quantum Effects and Applications, Hunan Normal University, Changsha 410081, People's Republic of China
| | - Xiao-Ping Li
- Research Laboratory for Quantum Materials, Singapore University of Technology and Design, 487372, Singapore
| | - Dariusz Kaczorowski
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wrocław, Poland
| | - Michael S Fuhrer
- School of Physics and Astronomy, Monash University, Clayton VIC 3800 Australia Monash Centre for Atomically Thin Materials, Monash University, Clayton VIC 3800, Australia
- Australian Research Council (ARC) Centre of Excellence for Low-Energy Electronics Technologies (FLEET), School of Physics, Monash University, Clayton VIC 3800, Australia
| | - Shengyuan A Yang
- Research Laboratory for Quantum Materials, Singapore University of Technology and Design, 487372, Singapore
| | - Bent Weber
- School of Physical and Mathematical Sciences, Nanyang Technological University, 637371, Singapore
- Australian Research Council (ARC) Centre of Excellence for Low-Energy Electronics Technologies (FLEET), School of Physics, Monash University, Clayton VIC 3800, Australia
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7
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Rakhlin M, Sorokin S, Galimov A, Eliseyev I, Davydov V, Kirilenko D, Toropov A, Shubina T. Allotropic Ga 2Se 3/GaSe nanostructures grown by van der Waals epitaxy: narrow exciton lines and single-photon emission. NANOSCALE 2024; 16:2039-2047. [PMID: 38204419 DOI: 10.1039/d3nr05674k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
The ability to emit narrow exciton lines, preferably with a clearly defined polarization, is one of the key conditions for the use of nanostructures based on III-VI monochalcogenides and other layered crystals in quantum technology to create non-classical light. Currently, the main method of their formation is exfoliation followed by strain and defect engineering. A factor limiting the use of epitaxy is the presence of different phases in the grown films. In this work, we show that control over their formation makes it possible to create structures with the desired properties. We propose Ga2Se3/GaSe nanostructures grown by van der Waals epitaxy with a high VI/III flux ratio as a source of narrow exciton lines. Actually, these nanostructures are a combination of allotropes: GaSe and Ga2Se3, consisting of the same atoms in different arrangements. The energy positions of the narrow lines are determined by the quantum confinement in Ga2Se3 inclusions of different sizes in the GaSe matrix, similar to quantum dots, and their linear polarization is due to the ordering of Ga vacancies in a certain crystalline direction in Ga2Se3. Such nanostructures exhibit single-photon emission with second-order correlation function g(2)(0) ∼ 0.10 at 10 K that makes them promising for quantum technologies.
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8
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Bianchi MG, Risplendi F, Re Fiorentin M, Cicero G. Engineering the Electrical and Optical Properties of WS 2 Monolayers via Defect Control. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2305162. [PMID: 38009517 PMCID: PMC10811516 DOI: 10.1002/advs.202305162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 09/25/2023] [Indexed: 11/29/2023]
Abstract
Two-dimensional (2D) materials as tungsten disulphide (WS2 ) are rising as the ideal platform for the next generation of nanoscale devices due to the excellent electric-transport and optical properties. However, the presence of defects in the as grown samples represents one of the main limiting factors for commercial applications. At the same time, WS2 properties are frequently tailored by introducing impurities at specific sites. Aim of this review paper is to present a complete description and discussion of the effects of both intentional and unintentional defects in WS2 , by an in depth analysis of the recent experimental and theoretical investigations reported in the literature. First, the most frequent intrinsic defects in WS2 are presented and their effects in the readily synthetized material are discussed. Possible solutions to remove and heal unintentional defects are also analyzed. Following, different doping schemes are reported, including the traditional substitution approach and innovative techniques based on the surface charge transfer with adsorbed atoms or molecules. The plethora of WS2 monolayer modifications presented in this review and the systematic analysis of the corresponding optical and electronic properties, represent strategic degrees of freedom the researchers may exploit to tailor WS2 optical and electronic properties for specific device applications.
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Affiliation(s)
- Michele Giovanni Bianchi
- Department of Applied Science and TechnologyPolitecnico di Torinocorso Duca degli Abruzzi 24Torino10129Italy
| | - Francesca Risplendi
- Department of Applied Science and TechnologyPolitecnico di Torinocorso Duca degli Abruzzi 24Torino10129Italy
| | - Michele Re Fiorentin
- Department of Applied Science and TechnologyPolitecnico di Torinocorso Duca degli Abruzzi 24Torino10129Italy
| | - Giancarlo Cicero
- Department of Applied Science and TechnologyPolitecnico di Torinocorso Duca degli Abruzzi 24Torino10129Italy
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9
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Guo S, Germanis S, Taniguchi T, Watanabe K, Withers F, Luxmoore IJ. Electrically Driven Site-Controlled Single Photon Source. ACS PHOTONICS 2023; 10:2549-2555. [PMID: 37602287 PMCID: PMC10436352 DOI: 10.1021/acsphotonics.3c00097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Indexed: 08/22/2023]
Abstract
Single photon sources are fundamental building blocks for quantum communication and computing technologies. In this work, we present a device geometry consisting of gold pillars embedded in a van der Waals heterostructure of graphene, hexagonal boron nitride, and tungsten diselenide. The gold pillars serve to both generate strain and inject charge carriers, allowing us to simultaneously demonstrate the positional control and electrical pumping of a single photon emitter. Moreover, increasing the thickness of the hexagonal boron nitride tunnel barriers restricts electroluminescence but enables electrical control of the emission energy of the site-controlled single photon emitters, with measured energy shifts reaching 40 meV.
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Affiliation(s)
- Shi Guo
- Department
of Physics and Astronomy, University of
Exeter, Exeter EX4 4QL, United
Kingdom
| | - Savvas Germanis
- Department
of Engineering, University of Exeter, Exeter EX4 4QF, United Kingdom
| | - 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
| | - Freddie Withers
- Department
of Physics and Astronomy, University of
Exeter, Exeter EX4 4QL, United
Kingdom
| | - Isaac J. Luxmoore
- Department
of Engineering, University of Exeter, Exeter EX4 4QF, United Kingdom
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10
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Zhou J, Thomas JC, Barre E, Barnard ES, Raja A, Cabrini S, Munechika K, Schwartzberg A, Weber-Bargioni A. Near-Field Coupling with a Nanoimprinted Probe for Dark Exciton Nanoimaging in Monolayer WSe 2. NANO LETTERS 2023. [PMID: 37262350 DOI: 10.1021/acs.nanolett.3c00621] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Tip-enhanced photoluminescence (TRPL) is a powerful technique for spatially and spectrally probing local optical properties of 2-dimensional (2D) materials that are modulated by the local heterogeneities, revealing inaccessible dark states due to bright state overlap in conventional far-field microscopy at room temperature. While scattering-type near-field probes have shown the potential to selectively enhance and reveal dark exciton emission, their technical complexity and sensitivity can pose challenges under certain experimental conditions. Here, we present a highly reproducible and easy-to-fabricate near-field probe based on nanoimprint lithography and fiber-optic excitation and collection. The novel near-field measurement configuration provides an ∼3 orders of magnitude out-of-plane Purcell enhancement, diffraction-limited excitation spot, and subdiffraction hyperspectral imaging resolution (below 50 nm) of dark exciton emission. The effectiveness of this high spatial XD mapping technique was then demonstrated through reproducible hyperspectral mapping of oxidized sites and bubble areas.
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Affiliation(s)
- Junze Zhou
- The Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - John C Thomas
- The Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Elyse Barre
- The Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Edward S Barnard
- The Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Archana Raja
- The Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Stefano Cabrini
- The Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Keiko Munechika
- HighRI Optics, Inc. 5401 Broadway Ter 304, Oakland, California 94618, United States
| | - Adam Schwartzberg
- The Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Alexander Weber-Bargioni
- The Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
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11
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Lee C, Schuck PJ. Photodarkening, Photobrightening, and the Role of Color Centers in Emerging Applications of Lanthanide-Based Upconverting Nanomaterials. Annu Rev Phys Chem 2023; 74:415-438. [PMID: 37093661 DOI: 10.1146/annurev-physchem-082720-032137] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Upconverting nanoparticles (UCNPs) compose a class of luminescent materials that utilize the unique wavelength-converting properties of lanthanide (Ln) ions for light-harvesting applications, photonics technologies, and biological imaging and sensing experiments. Recent advances in UCNP design have shed light on the properties of local color centers, both intrinsic and controllably induced, within these materials and their potential influence on UCNP photophysics. In this review, we describe fundamental studies of color centers in Ln-based materials, including research into their origins and their roles in observed photodarkening and photobrightening mechanisms. We place particular focus on the new functionalities that are enabled by harnessing the properties of color centers within Ln-doped nanocrystals, illustrated through applications in afterglow-based bioimaging, X-ray detection, all-inorganic nanocrystal photoswitching, and fully rewritable optical patterning and memory.
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Affiliation(s)
- Changhwan Lee
- Department of Mechanical Engineering, Columbia University, New York, NY, USA; ,
| | - P James Schuck
- Department of Mechanical Engineering, Columbia University, New York, NY, USA; ,
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12
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López LEP, Rosławska A, Scheurer F, Berciaud S, Schull G. Tip-induced excitonic luminescence nanoscopy of an atomically resolved van der Waals heterostructure. NATURE MATERIALS 2023; 22:482-488. [PMID: 36928383 DOI: 10.1038/s41563-023-01494-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 01/30/2023] [Indexed: 06/18/2023]
Abstract
The electronic and optical properties of van der Waals heterostructures are strongly influenced by the structuration and homogeneity of their nano- and atomic-scale environments. Unravelling this intimate structure-property relationship is a key challenge that requires methods capable of addressing the light-matter interactions in van der Waals materials with ultimate spatial resolution. Here we use a low-temperature scanning tunnelling microscope to probe-with atomic-scale resolution-the excitonic luminescence of a van der Waals heterostructure, made of a transition metal dichalcogenide monolayer stacked onto a few-layer graphene flake supported by a Au(111) substrate. Sharp emission lines arising from neutral, charged and localized excitons are reported. Their intensities and emission energies vary as a function of the nanoscale topography of the van der Waals heterostructure, explaining the variability of the emission properties observed with diffraction-limited approaches. Our work paves the way towards understanding and controlling optoelectronic phenomena in moiré superlattices with atomic-scale resolution.
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Affiliation(s)
- Luis E Parra López
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, Strasbourg, France
| | - Anna Rosławska
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, Strasbourg, France
| | - Fabrice Scheurer
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, Strasbourg, France
| | - Stéphane Berciaud
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, Strasbourg, France.
| | - Guillaume Schull
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, Strasbourg, France.
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13
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Chen FXR, Lin CY, Siao HY, Jian CY, Yang YC, Lin CL. Deep learning based atomic defect detection framework for two-dimensional materials. Sci Data 2023; 10:91. [PMID: 36788235 PMCID: PMC9929095 DOI: 10.1038/s41597-023-02004-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 02/06/2023] [Indexed: 02/16/2023] Open
Abstract
Defects to popular two-dimensional (2D) transition metal dichalcogenides (TMDs) seriously lower the efficiency of field-effect transistor (FET) and depress the development of 2D materials. These atomic defects are mainly identified and researched by scanning tunneling microscope (STM) because it can provide precise measurement without harming the samples. The long analysis time of STM for locating defects in images has been solved by combining feature detection with convolutional neural networks (CNN). However, the low signal-noise ratio, insufficient data, and a large amount of TMDs members make the automatic defect detection system hard to be applied. In this study, we propose a deep learning-based atomic defect detection framework (DL-ADD) to efficiently detect atomic defects in molybdenum disulfide (MoS2) and generalize the model for defect detection in other TMD materials. We design DL-ADD with data augmentation, color preprocessing, noise filtering, and a detection model to improve detection quality. The DL-ADD provides precise detection in MoS2 (F2-scores is 0.86 on average) and good generality to WS2 (F2-scores is 0.89 on average).
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Affiliation(s)
- Fu-Xiang Rikudo Chen
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu City, Taiwan
| | - Chia-Yu Lin
- Department of Computer Science and Information Engineering, National Central University, Taoyuan City, Taiwan.
| | - Hui-Ying Siao
- Department of Electrical and Computer Engineering, University of California, Davis, CA, USA
| | - Cheng-Yuan Jian
- Department of Computer Science and Engineering, Yuan Ze University, Taoyuan City, Taiwan
| | - Yong-Cheng Yang
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu City, Taiwan
| | - Chun-Liang Lin
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu City, Taiwan
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14
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Fu Q, Dai J, Huang X, Dai Y, Pan Y, Yang L, Sun Z, Miao T, Zhou M, Zhao L, Zhao W, Han X, Lu J, Gao H, Zhou X, Wang Y, Ni Z, Ji W, Huang Y. One-Step Exfoliation Method for Plasmonic Activation of Large-Area 2D Crystals. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2204247. [PMID: 36104244 PMCID: PMC9661865 DOI: 10.1002/advs.202204247] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Indexed: 06/01/2023]
Abstract
Advanced exfoliation techniques are crucial for exploring the intrinsic properties and applications of 2D materials. Though the recently discovered Au-enhanced exfoliation technique provides an effective strategy for the preparation of large-scale 2D crystals, the high cost of gold hinders this method from being widely adopted in industrial applications. In addition, direct Au contact could significantly quench photoluminescence (PL) emission in 2D semiconductors. It is therefore crucial to find alternative metals that can replace gold to achieve efficient exfoliation of 2D materials. Here, the authors present a one-step Ag-assisted method that can efficiently exfoliate many large-area 2D monolayers, where the yield ratio is comparable to Au-enhanced exfoliation method. Differing from Au film, however, the surface roughness of as-prepared Ag films on SiO2 /Si substrate is much higher, which facilitates the generation of surface plasmons resulting from the nanostructures formed on the rough Ag surface. More interestingly, the strong coupling between 2D semiconductor crystals (e.g., MoS2 , MoSe2 ) and Ag film leads to a unique PL enhancement that has not been observed in other mechanical exfoliation techniques, which can be mainly attributed to enhanced light-matter interaction as a result of extended propagation of surface plasmonic polariton (SPP). This work provides a lower-cost and universal Ag-assisted exfoliation method, while at the same time offering enhanced SPP-matter interactions.
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Affiliation(s)
- Qiang Fu
- Advanced Research Institute of Multidisciplinary ScienceBeijing Institute of TechnologyBeijing100081P. R. China
- School of Physics and Key Laboratory of MEMS of the Ministry of EducationSoutheast UniversityNanjing211189P. R. China
- Institute of PhysicsChinese Academy of ScienceBeijing100190P. R. China
| | - Jia‐Qi Dai
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & Micro‐Nano DevicesRenmin University of ChinaBeijing100872P. R. China
| | - Xin‐Yu Huang
- Advanced Research Institute of Multidisciplinary ScienceBeijing Institute of TechnologyBeijing100081P. R. China
| | - Yun‐Yun Dai
- Advanced Research Institute of Multidisciplinary ScienceBeijing Institute of TechnologyBeijing100081P. R. China
| | - Yu‐Hao Pan
- China North Vehicle Research InstituteBeijing100072P. R. China
| | - Long‐Long Yang
- Institute of PhysicsChinese Academy of ScienceBeijing100190P. R. China
| | - Zhen‐Yu Sun
- Institute of PhysicsChinese Academy of ScienceBeijing100190P. R. China
| | - Tai‐Min Miao
- Institute of PhysicsChinese Academy of ScienceBeijing100190P. R. China
| | - Meng‐Fan Zhou
- School of Physics and Key Laboratory of MEMS of the Ministry of EducationSoutheast UniversityNanjing211189P. R. China
| | - Lin Zhao
- Institute of PhysicsChinese Academy of ScienceBeijing100190P. R. China
- Songshan Lake Materials LaboratoryDongguan523808P. R. China
| | - Wei‐Jie Zhao
- School of Physics and Key Laboratory of MEMS of the Ministry of EducationSoutheast UniversityNanjing211189P. R. China
| | - Xu Han
- Advanced Research Institute of Multidisciplinary ScienceBeijing Institute of TechnologyBeijing100081P. R. China
- Institute of PhysicsChinese Academy of ScienceBeijing100190P. R. China
| | - Jun‐Peng Lu
- School of Physics and Key Laboratory of MEMS of the Ministry of EducationSoutheast UniversityNanjing211189P. R. China
| | - Hong‐Jun Gao
- Institute of PhysicsChinese Academy of ScienceBeijing100190P. R. China
- University of Chinese Academy of SciencesBeijing100049P. R. China
| | - Xing‐Jiang Zhou
- Institute of PhysicsChinese Academy of ScienceBeijing100190P. R. China
- Songshan Lake Materials LaboratoryDongguan523808P. R. China
- University of Chinese Academy of SciencesBeijing100049P. R. China
| | - Ye‐Liang Wang
- Advanced Research Institute of Multidisciplinary ScienceBeijing Institute of TechnologyBeijing100081P. R. China
| | - Zhen‐Hua Ni
- School of Physics and Key Laboratory of MEMS of the Ministry of EducationSoutheast UniversityNanjing211189P. R. China
| | - Wei Ji
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & Micro‐Nano DevicesRenmin University of ChinaBeijing100872P. R. China
| | - Yuan Huang
- Advanced Research Institute of Multidisciplinary ScienceBeijing Institute of TechnologyBeijing100081P. R. China
- Institute of PhysicsChinese Academy of ScienceBeijing100190P. R. China
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15
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García de Abajo FJ, Dias EJC, Di Giulio V. Complete Excitation of Discrete Quantum Systems by Single Free Electrons. PHYSICAL REVIEW LETTERS 2022; 129:093401. [PMID: 36083663 DOI: 10.1103/physrevlett.129.093401] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 07/26/2022] [Indexed: 06/15/2023]
Abstract
We reveal a wealth of nonlinear and recoil effects in the interaction between individual low-energy electrons (≲100 eV) and samples comprising a discrete number of states. Adopting a quantum theoretical description of combined free-electron and two-level systems, we find a maximum achievable excitation probability of 100%, which requires specific conditions relating to the coupling strength and the transition symmetry, as we illustrate through calculations for dipolar and quadrupolar modes. Strong recoil effects are observed when the kinetic energy of the probe lies close to the transition threshold, although the associated probability remains independent of the electron wave function even when fully accounting for nonlinear interactions with arbitrarily complex multilevel samples. Our work reveals the potential of free electrons to control localized excitations and delineates the boundaries of such control.
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Affiliation(s)
- F Javier García de Abajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Spain
| | - Eduardo J C Dias
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
| | - Valerio Di Giulio
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
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16
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Pal A, Zhang S, Chavan T, Agashiwala K, Yeh CH, Cao W, Banerjee K. Quantum-Engineered Devices Based on 2D Materials for Next-Generation Information Processing and Storage. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022:e2109894. [PMID: 35468661 DOI: 10.1002/adma.202109894] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 04/11/2022] [Indexed: 06/14/2023]
Abstract
As an approximation to the quantum state of solids, the band theory, developed nearly seven decades ago, fostered the advance of modern integrated solid-state electronics, one of the most successful technologies in the history of human civilization. Nonetheless, their rapidly growing energy consumption and accompanied environmental issues call for more energy-efficient electronics and optoelectronics, which necessitate the exploration of more advanced quantum mechanical effects, such as band-to-band tunneling, spin-orbit coupling, spin-valley locking, and quantum entanglement. The emerging 2D layered materials, featured by their exotic electrical, magnetic, optical, and structural properties, provide a revolutionary low-dimensional and manufacture-friendly platform (and many more opportunities) to implement these quantum-engineered devices, compared to the traditional electronic materials system. Here, the progress in quantum-engineered devices is reviewed and the opportunities/challenges of exploiting 2D materials are analyzed to highlight their unique quantum properties that enable novel energy-efficient devices, and useful insights to quantum device engineers and 2D-material scientists are provided.
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Affiliation(s)
- Arnab Pal
- ECE Department, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Shuo Zhang
- ECE Department, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
- College of ISEE, Zhejiang University, Hangzhou, 310027, China
| | - Tanmay Chavan
- ECE Department, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Kunjesh Agashiwala
- ECE Department, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Chao-Hui Yeh
- ECE Department, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Wei Cao
- ECE Department, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Kaustav Banerjee
- ECE Department, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
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17
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Ignatova T, Pourianejad S, Li X, Schmidt K, Aryeetey F, Aravamudhan S, Rotkin SV. Multidimensional Imaging Reveals Mechanisms Controlling Multimodal Label-Free Biosensing in Vertical 2DM-Heterostructures. ACS NANO 2022; 16:2598-2607. [PMID: 35061372 DOI: 10.1021/acsnano.1c09335] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Two-dimensional materials and their van der Waals heterostructures enable a large range of applications, including label-free biosensing. Lattice mismatch and work function difference in the heterostructure material result in strain and charge transfer, often varying at a nanometer scale, that influence device performance. In this work, a multidimensional optical imaging technique is developed in order to map subdiffractional distributions for doping and strain and understand the role of those for modulation of the electronic properties of the material. As an example, vertical heterostructures comprised of monolayer graphene and single-layer flakes of transition metal dichalcogenide MoS2 were fabricated and used for biosensing. Herein, the optical label-free detection of doxorubicin, a common cancer drug, is reported via three independent optical detection channels (photoluminescence shift, Raman shift, and graphene enhanced Raman scattering). Non-uniform broadening of components of multimodal signal correlates with the statistical distribution of local optical properties of the heterostructure. Multidimensional nanoscale imaging allows one to reveal the physical origin for such a local response and propose the best strategy for the mitigation of materials variability and future device fabrication, enabling multiplexed biosensing.
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Affiliation(s)
- Tetyana Ignatova
- Department of Nanoscience, University of North Carolina at Greensboro, 2907 East Gate City Boulevard, Greensboro, North Carolina 27401, United States
| | - Sajedeh Pourianejad
- Department of Nanoscience, University of North Carolina at Greensboro, 2907 East Gate City Boulevard, Greensboro, North Carolina 27401, United States
| | - Xinyi Li
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Kirby Schmidt
- Department of Nanoscience, University of North Carolina at Greensboro, 2907 East Gate City Boulevard, Greensboro, North Carolina 27401, United States
| | - Frederick Aryeetey
- Department of Nanoengineering, North Carolina A&T State University, 2907 East Gate City Boulevard, Greensboro, North Carolina 27401, United States
| | - Shyam Aravamudhan
- Department of Nanoengineering, North Carolina A&T State University, 2907 East Gate City Boulevard, Greensboro, North Carolina 27401, United States
| | - Slava V Rotkin
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Materials Research Institute, The Pennsylvania State University, Millennium Science Complex, University Park, Pennsylvania 16802, United States
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18
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Nguyen TD, Jiang J, Song B, Tran MD, Choi W, Kim JH, Kim Y, Duong DL, Lee YH. Gate-Tunable Magnetism via Resonant Se-Vacancy Levels in WSe 2. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2102911. [PMID: 34713632 PMCID: PMC8693072 DOI: 10.1002/advs.202102911] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 09/19/2021] [Indexed: 05/16/2023]
Abstract
The confined defects in 2D van der Waals (vdW)-layered semiconductors can be easily tailored using charge doping, strain, or an electric field. Nevertheless, gate-tunable magnetic order via intrinsic defects has been rarely observed to date. Herein, a gate-tunable magnetic order via resonant Se vacancies in WSe2 is demonstrated. The Se-vacancy states are probed via photocurrent measurements with gating to convert unoccupied states to partially occupied states associated with photo-excited carrier recombination. The magneto-photoresistance hysteresis is modulated by gating, which is consistent with the density functional calculations. The two energy levels associated with Se vacancies split with increasing laser power, owing to the robust Coulomb interaction and strong spin-orbit coupling. The findings offer a new approach for controlling the magnetic properties of defects in optoelectronic and spintronic devices using vdW-layered semiconductors.
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Affiliation(s)
- Tuan Dung Nguyen
- Center for Integrated Nanostructure Physics (CINAP)Institute for Basic Science (IBS)Suwon16419Republic of Korea
- Department of Energy ScienceSungkyunkwan UniversitySuwon16419Republic of Korea
| | - Jinbao Jiang
- Center for Integrated Nanostructure Physics (CINAP)Institute for Basic Science (IBS)Suwon16419Republic of Korea
- School of Microelectronics Science and TechnologySun Yat‐sen UniversityZhuhai519082China
| | - Bumsub Song
- Center for Integrated Nanostructure Physics (CINAP)Institute for Basic Science (IBS)Suwon16419Republic of Korea
- Department of Energy ScienceSungkyunkwan UniversitySuwon16419Republic of Korea
| | - Minh Dao Tran
- Center for Integrated Nanostructure Physics (CINAP)Institute for Basic Science (IBS)Suwon16419Republic of Korea
| | - Wooseon Choi
- Department of Energy ScienceSungkyunkwan UniversitySuwon16419Republic of Korea
| | - Ji Hee Kim
- Center for Integrated Nanostructure Physics (CINAP)Institute for Basic Science (IBS)Suwon16419Republic of Korea
- Department of Energy ScienceSungkyunkwan UniversitySuwon16419Republic of Korea
| | - Young‐Min Kim
- Center for Integrated Nanostructure Physics (CINAP)Institute for Basic Science (IBS)Suwon16419Republic of Korea
- Department of Energy ScienceSungkyunkwan UniversitySuwon16419Republic of Korea
| | - Dinh Loc Duong
- Center for Integrated Nanostructure Physics (CINAP)Institute for Basic Science (IBS)Suwon16419Republic of Korea
- Department of Energy ScienceSungkyunkwan UniversitySuwon16419Republic of Korea
| | - Young Hee Lee
- Center for Integrated Nanostructure Physics (CINAP)Institute for Basic Science (IBS)Suwon16419Republic of Korea
- Department of Energy ScienceSungkyunkwan UniversitySuwon16419Republic of Korea
- Department of PhysicsSungkyunkwan UniversitySuwon16419Republic of Korea
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19
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Stewart JC, Fan Y, Danial JSH, Goetz A, Prasad AS, Burton OJ, Alexander-Webber JA, Lee SF, Skoff SM, Babenko V, Hofmann S. Quantum Emitter Localization in Layer-Engineered Hexagonal Boron Nitride. ACS NANO 2021; 15:13591-13603. [PMID: 34347438 DOI: 10.1021/acsnano.1c04467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Hexagonal boron nitride (hBN) is a promising host material for room-temperature, tunable solid-state quantum emitters. A key technological challenge is deterministic and scalable spatial emitter localization, both laterally and vertically, while maintaining the full advantages of the 2D nature of the material. Here, we demonstrate emitter localization in hBN in all three dimensions via a monolayer (ML) engineering approach. We establish pretreatment processes for hBN MLs to either fully suppress or activate emission, thereby enabling such differently treated MLs to be used as select building blocks to achieve vertical (z) emitter localization at the atomic layer level. We show that emitter bleaching of ML hBN can be suppressed by sandwiching between two protecting hBN MLs, and that such thin stacks retain opportunities for external control of emission. We exploit this to achieve lateral (x-y) emitter localization via the addition of a patterned graphene mask that quenches fluorescence. Such complete emitter site localization is highly versatile, compatible with planar, scalable processing, allowing tailored approaches to addressable emitter array designs for advanced characterization, monolithic device integration, and photonic circuits.
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Affiliation(s)
- James Callum Stewart
- Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom
| | - Ye Fan
- Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom
| | - John S H Danial
- The Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Alexander Goetz
- Institute of Atomic and Subatomic Physics, Vienna University of Technology, Stadionallee 2, 1020 Vienna, Austria
| | - Adarsh S Prasad
- Institute of Atomic and Subatomic Physics, Vienna University of Technology, Stadionallee 2, 1020 Vienna, Austria
| | - Oliver J Burton
- Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom
| | - Jack A Alexander-Webber
- Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom
| | - Steven F Lee
- The Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Sarah M Skoff
- Institute of Atomic and Subatomic Physics, Vienna University of Technology, Stadionallee 2, 1020 Vienna, Austria
| | - Vitaliy Babenko
- Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom
| | - Stephan Hofmann
- Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom
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20
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Anantharaman SB, Jo K, Jariwala D. Exciton-Photonics: From Fundamental Science to Applications. ACS NANO 2021; 15:12628-12654. [PMID: 34310122 DOI: 10.1021/acsnano.1c02204] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Semiconductors in all dimensionalities ranging from 0D quantum dots and molecules to 3D bulk crystals support bound electron-hole pair quasiparticles termed excitons. Over the past two decades, the emergence of a variety of low-dimensional semiconductors that support excitons combined with advances in nano-optics and photonics has burgeoned an advanced area of research that focuses on engineering, imaging, and modulating the coupling between excitons and photons, resulting in the formation of hybrid quasiparticles termed exciton-polaritons. This advanced area has the potential to bring about a paradigm shift in quantum optics, as well as classical optoelectronic devices. Here, we present a review on the coupling of light in excitonic semiconductors and previous investigations of the optical properties of these hybrid quasiparticles via both far-field and near-field imaging and spectroscopy techniques. Special emphasis is given to recent advances with critical evaluation of the bottlenecks that plague various materials toward practical device implementations including quantum light sources. Our review highlights a growing need for excitonic material development together with optical engineering and imaging techniques to harness the utility of excitons and their host materials for a variety of applications.
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Affiliation(s)
- Surendra B Anantharaman
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Kiyoung Jo
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Deep Jariwala
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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21
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García
de Abajo FJ, Di Giulio V. Optical Excitations with Electron Beams: Challenges and Opportunities. ACS PHOTONICS 2021; 8:945-974. [PMID: 35356759 PMCID: PMC8939335 DOI: 10.1021/acsphotonics.0c01950] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/17/2021] [Accepted: 02/19/2021] [Indexed: 05/20/2023]
Abstract
Free electron beams such as those employed in electron microscopes have evolved into powerful tools to investigate photonic nanostructures with an unrivaled combination of spatial and spectral precision through the analysis of electron energy losses and cathodoluminescence light emission. In combination with ultrafast optics, the emerging field of ultrafast electron microscopy utilizes synchronized femtosecond electron and light pulses that are aimed at the sampled structures, holding the promise to bring simultaneous sub-Å-sub-fs-sub-meV space-time-energy resolution to the study of material and optical-field dynamics. In addition, these advances enable the manipulation of the wave function of individual free electrons in unprecedented ways, opening sound prospects to probe and control quantum excitations at the nanoscale. Here, we provide an overview of photonics research based on free electrons, supplemented by original theoretical insights and discussion of several stimulating challenges and opportunities. In particular, we show that the excitation probability by a single electron is independent of its wave function, apart from a classical average over the transverse beam density profile, whereas the probability for two or more modulated electrons depends on their relative spatial arrangement, thus reflecting the quantum nature of their interactions. We derive first-principles analytical expressions that embody these results and have general validity for arbitrarily shaped electrons and any type of electron-sample interaction. We conclude with some perspectives on various exciting directions that include disruptive approaches to noninvasive spectroscopy and microscopy, the possibility of sampling the nonlinear optical response at the nanoscale, the manipulation of the density matrices associated with free electrons and optical sample modes, and appealing applications in optical modulation of electron beams, all of which could potentially revolutionize the use of free electrons in photonics.
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Affiliation(s)
- F. Javier García
de Abajo
- ICFO-Institut
de Ciencies Fotoniques, The Barcelona Institute
of Science and Technology, 08860 Castelldefels, Barcelona, Spain
- ICREA-Institució
Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Spain
- E-mail:
| | - Valerio Di Giulio
- ICFO-Institut
de Ciencies Fotoniques, The Barcelona Institute
of Science and Technology, 08860 Castelldefels, Barcelona, Spain
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22
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Liang Q, Zhang Q, Zhao X, Liu M, Wee ATS. Defect Engineering of Two-Dimensional Transition-Metal Dichalcogenides: Applications, Challenges, and Opportunities. ACS NANO 2021; 15:2165-2181. [PMID: 33449623 DOI: 10.1021/acsnano.0c09666] [Citation(s) in RCA: 97] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Atomic defects, being the most prevalent zero-dimensional topological defects, are ubiquitous in a wide range of 2D transition-metal dichalcogenides (TMDs). They could be intrinsic, formed during the initial sample growth, or created by postprocessing. Despite the majority of TMDs being largely unaffected after losing chalcogen atoms in the outermost layer, a spectrum of properties, including optical, electrical, and chemical properties, can be significantly modulated, and potentially invoke applicable functionalities utilized in many applications. Hence, controlling chalcogen atomic defects provides an alternative avenue for engineering a wide range of physical and chemical properties of 2D TMDs. In this article, we review recent progress on the role of chalcogen atomic defects in engineering 2D TMDs, with a particular focus on device performance improvements. Various approaches for creating chalcogen atomic defects including nonstoichiometric synthesis and postgrowth treatment, together with their characterization and interpretation are systematically overviewed. The tailoring of optical, electrical, and magnetic properties, along with the device performance enhancement in electronic, optoelectronic, chemical sensing, biomedical, and catalytic activity are discussed in detail. Postformation dynamic evolution and repair of chalcogen atomic defects are also introduced. Finally, we offer our perspective on the challenges and opportunities in this field.
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Affiliation(s)
- Qijie Liang
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117551, Singapore
| | - Qian Zhang
- Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117575, Singapore
| | - Xiaoxu Zhao
- Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117575, Singapore
| | - Meizhuang Liu
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117551, Singapore
| | - Andrew T S Wee
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117551, Singapore
- Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore
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