1
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Yu C, Cao J, Zhu S, Dai Z. Preparation and Modeling of Graphene Bubbles to Obtain Strain-Induced Pseudomagnetic Fields. MATERIALS (BASEL, SWITZERLAND) 2024; 17:2889. [PMID: 38930258 PMCID: PMC11204662 DOI: 10.3390/ma17122889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 06/08/2024] [Accepted: 06/11/2024] [Indexed: 06/28/2024]
Abstract
It has been both theoretically predicted and experimentally demonstrated that strain can effectively modulate the electronic states of graphene sheets through the creation of a pseudomagnetic field (PMF). Pressurizing graphene sheets into bubble-like structures has been considered a viable approach for the strain engineering of PMFs. However, the bubbling technique currently faces limitations such as long manufacturing time, low durability, and challenges in precise control over the size and shape of the pressurized bubble. Here, we propose a rapid bubbling method based on an oxygen plasma chemical reaction to achieve rapid induction of out-of-plane deflections and in-plane strains in graphene sheets. We introduce a numerical scheme capable of accurately resolving the strain field and resulting PMFs within the pressurized graphene bubbles, even in cases where the bubble shape deviates from perfect spherical symmetry. The results provide not only insights into the strain engineering of PMFs in graphene but also a platform that may facilitate the exploration of the strain-mediated electronic behaviors of a variety of other 2D materials.
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Affiliation(s)
- Chuanli Yu
- Department of Mechanics and Engineering Science, State Key Laboratory for Turbulence and Complex Systems, College of Engineering, Peking University, Beijing 100871, China; (C.Y.); (J.C.)
| | - Jiacong Cao
- Department of Mechanics and Engineering Science, State Key Laboratory for Turbulence and Complex Systems, College of Engineering, Peking University, Beijing 100871, China; (C.Y.); (J.C.)
| | - Shuze Zhu
- Center for X-Mechanics, Department of Engineering Mechanics, Institute of Applied Mechanics, Zhejiang University, Hangzhou 310000, China;
| | - Zhaohe Dai
- Department of Mechanics and Engineering Science, State Key Laboratory for Turbulence and Complex Systems, College of Engineering, Peking University, Beijing 100871, China; (C.Y.); (J.C.)
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2
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Liu H, Lai Q, Fu J, Zhang S, Fu Z, Zeng H. Reversible flexoelectric domain engineering at the nanoscale in van der Waals ferroelectrics. Nat Commun 2024; 15:4556. [PMID: 38811549 PMCID: PMC11136971 DOI: 10.1038/s41467-024-48892-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Accepted: 05/16/2024] [Indexed: 05/31/2024] Open
Abstract
The universal flexoelectric effect in solids provides a mechanical pathway for controlling electric polarization in ultrathin ferroelectrics, eliminating potential material breakdown from a giant electric field at the nanoscale. One challenge of this approach is arbitrary implementation, which is strongly hindered by one-way switching capability. Here, utilizing the innate flexibility of van der Waals materials, we demonstrate that ferroelectric polarization and domain structures can be mechanically, reversibly, and arbitrarily switched in two-dimensional CuInP2S6 via the nano-tip imprinting technique. The bidirectional flexoelectric control is attributed to the extended tip-induced deformation in two-dimensional systems with innate flexibility at the atomic scale. By employing an elastic substrate, artificial ferroelectric nanodomains with lateral sizes as small as ~80 nm are noninvasively generated in an area of 1 μm2, equal to a density of 31.4 Gbit/in2. Our results highlight the potential applications of van der Waals ferroelectrics in data storage and flexoelectronics.
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Affiliation(s)
- Heng Liu
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, 230026, China
- CAS Key Laboratory of Strongly Coupled Quantum Matter Physics, Department of Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, 230088, China
| | - Qinglin Lai
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, 230026, China
- CAS Key Laboratory of Strongly Coupled Quantum Matter Physics, Department of Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, 230088, China
| | - Jun Fu
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, 230026, China
- CAS Key Laboratory of Strongly Coupled Quantum Matter Physics, Department of Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, 230088, China
| | - Shijie Zhang
- College of Physics and Electronic Information, Yunnan Normal University, Kunming, 650500, China
- Yunnan Key Laboratory of Opto-Electronic Information Technology, Kunming, 650500, China
| | - Zhaoming Fu
- College of Physics and Electronic Information, Yunnan Normal University, Kunming, 650500, China
- Yunnan Key Laboratory of Opto-Electronic Information Technology, Kunming, 650500, China
| | - Hualing Zeng
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, 230026, China.
- CAS Key Laboratory of Strongly Coupled Quantum Matter Physics, Department of Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China.
- Hefei National Laboratory, University of Science and Technology of China, Hefei, 230088, China.
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3
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Stellino E, D'Alò B, Blundo E, Postorino P, Polimeni A. Fine-Tuning of the Excitonic Response in Monolayer WS 2 Domes via Coupled Pressure and Strain Variation. NANO LETTERS 2024; 24:3945-3951. [PMID: 38506837 DOI: 10.1021/acs.nanolett.4c00157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/21/2024]
Abstract
We present a spectroscopic investigation of the vibrational and optoelectronic properties of WS2 domes in the 0-0.65 GPa range. The pressure evolution of the system morphology, deduced by the combined analysis of Raman and photoluminescence spectra, revealed a significant variation in the dome's aspect ratio. The modification of the dome shape caused major changes in the mechanical properties of the system resulting in a sizable increase of the out-of-plane compressive strain while keeping the in-plane tensile strain unchanged. The variation of the strain gradients drives a nonlinear behavior in both the exciton energy and radiative recombination intensity, interpreted as the consequence of a hybridization mechanism between the electronic states of two distinct minima in the conduction band. Our results indicate that pressure and strain can be efficiently combined in low dimensional systems with unconventional morphology to obtain modulations of the electronic band structure not achievable in planar crystals.
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Affiliation(s)
- Elena Stellino
- Department of Basic and Applied Sciences for Engineering, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Roma, Italy
| | - Beatrice D'Alò
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Roma, Italy
| | - Elena Blundo
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Roma, Italy
| | - Paolo Postorino
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Roma, Italy
| | - Antonio Polimeni
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Roma, Italy
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4
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Krumland J, Velja S, Cocchi C. Quantum Dots in Transition Metal Dichalcogenides Induced by Atomic-Scale Deformations. ACS PHOTONICS 2024; 11:586-595. [PMID: 38405397 PMCID: PMC10885200 DOI: 10.1021/acsphotonics.3c01470] [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: 10/12/2023] [Revised: 12/20/2023] [Accepted: 12/20/2023] [Indexed: 02/27/2024]
Abstract
Single-photon emission from monolayer transition metal dichalcogenides requires the existence of localized, atom-like states within the extended material. Here, we predict from first-principles the existence of quantum dots around atomic-scale protrusions, which result from substrate roughness or particles trapped between layers. Using density functional theory, we find such deformations to give rise to local membrane stretching and curvature, which lead to the emergence of gap states. Having enhanced outer-surface localization, they are prone to mixing with states pertaining to chalcogen vacancies and adsorbates. If the deformation is sharp, the conduction band minimum furthermore assumes atomic and valley-mixed character, potentially enabling quantum light emission. When such structural defects are arranged in an array, the new states couple to form energetically separated sub-bands, holding promise for intriguing superlattice dynamics. All of the observed features are shown to be closely linked to elastic, deformation-induced intra- and intervalley scattering processes.
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Affiliation(s)
- Jannis Krumland
- Institute
of Physics, Carl von Ossietzky Universität
Oldenburg, 26129 Oldenburg, Germany
- Physics
Department and IRIS Adlershof, Humboldt-Universität
zu Berlin, 12489 Berlin, Germany
| | - Stefan Velja
- Institute
of Physics, Carl von Ossietzky Universität
Oldenburg, 26129 Oldenburg, Germany
| | - Caterina Cocchi
- Institute
of Physics, Carl von Ossietzky Universität
Oldenburg, 26129 Oldenburg, Germany
- Physics
Department and IRIS Adlershof, Humboldt-Universität
zu Berlin, 12489 Berlin, Germany
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5
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Wang J, He L, Zhang Y, Nong H, Li S, Wu Q, Tan J, Liu B. Locally Strained 2D Materials: Preparation, Properties, and Applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024:e2314145. [PMID: 38339886 DOI: 10.1002/adma.202314145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2023] [Revised: 01/28/2024] [Indexed: 02/12/2024]
Abstract
2D materials are promising for strain engineering due to their atomic thickness and exceptional mechanical properties. In particular, non-uniform and localized strain can be induced in 2D materials by generating out-of-plane deformations, resulting in novel phenomena and properties, as witnessed in recent years. Therefore, the locally strained 2D materials are of great value for both fundamental studies and practical applications. This review discusses techniques for introducing local strains to 2D materials, and their feasibility, advantages, and challenges. Then, the unique effects and properties that arise from local strain are explored. The representative applications based on locally strained 2D materials are illustrated, including memristor, single photon emitter, and photodetector. Finally, concluding remarks on the challenges and opportunities in the emerging field of locally strained 2D materials are provided.
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Affiliation(s)
- Jingwei Wang
- Shenzhen Geim Graphene Center, Tsinghua-Berkeley Shenzhen Institute and Institute of Materials Research, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, P. R. China
| | - Liqiong He
- Shenzhen Geim Graphene Center, Tsinghua-Berkeley Shenzhen Institute and Institute of Materials Research, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, P. R. China
| | - Yunhao Zhang
- Shenzhen Geim Graphene Center, Tsinghua-Berkeley Shenzhen Institute and Institute of Materials Research, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, P. R. China
| | - Huiyu Nong
- Shenzhen Geim Graphene Center, Tsinghua-Berkeley Shenzhen Institute and Institute of Materials Research, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, P. R. China
| | - Shengnan Li
- Shenzhen Geim Graphene Center, Tsinghua-Berkeley Shenzhen Institute and Institute of Materials Research, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, P. R. China
| | - Qinke Wu
- Shenzhen Geim Graphene Center, Tsinghua-Berkeley Shenzhen Institute and Institute of Materials Research, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, P. R. China
| | - Junyang Tan
- Shenzhen Geim Graphene Center, Tsinghua-Berkeley Shenzhen Institute and Institute of Materials Research, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, P. R. China
| | - Bilu Liu
- Shenzhen Geim Graphene Center, Tsinghua-Berkeley Shenzhen Institute and Institute of Materials Research, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, P. R. China
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6
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Di Giorgio C, Blundo E, Basset J, Pettinari G, Felici M, Quay CHL, Rohart S, Polimeni A, Bobba F, Aprili M. Imaging the Quantum Capacitance of Strained MoS 2 Monolayers by Electrostatic Force Microscopy. ACS NANO 2024; 18:3405-3413. [PMID: 38236606 DOI: 10.1021/acsnano.3c10393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
We implemented radio frequency-assisted electrostatic force microscopy (RF-EFM) to investigate the electric field response of biaxially strained molybdenum disulfide (MoS2) monolayers (MLs) in the form of mesoscopic bubbles, produced via hydrogen (H)-ion irradiation of the bulk crystal. MoS2 ML, a semiconducting transition metal dichalcogenide, has recently attracted significant attention due to its promising optoelectronic properties, further tunable by strain. Here, we take advantage of the RF excitation to distinguish the intrinsic quantum capacitance of the strained ML from that due to atomic scale defects, presumably sulfur vacancies or H-passivated sulfur vacancies. In fact, at frequencies fRF larger than the inverse defect trapping time, the defect contribution to the total capacitance and to transport is negligible. Using RF-EFM at fRF = 300 MHz, we visualize simultaneously the bubble topography and its quantum capacitance. Our finite-frequency capacitance imaging technique is noninvasive and nanoscale and can contribute to the investigation of time- and spatial-dependent phenomena, such as the electron compressibility in quantum materials, which are difficult to measure by other methods.
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Affiliation(s)
- Cinzia Di Giorgio
- Department of Physics E.R. Caianiello, University of Salerno, Fisciano, 84084, Italy
- Laboratoire de Physique des Solides, Centre National de la Recherche Scientifique (CNRS), Université Paris-Saclay, Orsay, 91405, France
| | - Elena Blundo
- Physics Department, Sapienza University of Rome, Rome, 00185, Italy
| | - Julien Basset
- Laboratoire de Physique des Solides, Centre National de la Recherche Scientifique (CNRS), Université Paris-Saclay, Orsay, 91405, France
| | - Giorgio Pettinari
- Institute for Photonics and Nanotechnologies, National Research Council (CNR-IFN), Rome, 00133, Italy
| | - Marco Felici
- Physics Department, Sapienza University of Rome, Rome, 00185, Italy
| | - Charis H L Quay
- Laboratoire de Physique des Solides, Centre National de la Recherche Scientifique (CNRS), Université Paris-Saclay, Orsay, 91405, France
| | - Stanislas Rohart
- Laboratoire de Physique des Solides, Centre National de la Recherche Scientifique (CNRS), Université Paris-Saclay, Orsay, 91405, France
| | - Antonio Polimeni
- Physics Department, Sapienza University of Rome, Rome, 00185, Italy
| | - Fabrizio Bobba
- Department of Physics E.R. Caianiello, University of Salerno, Fisciano, 84084, Italy
- SuPerconducting and other INnovative materials and devices institute, National Research Council (CNR-SPIN), Fisciano, 84084, Italy
| | - Marco Aprili
- Laboratoire de Physique des Solides, Centre National de la Recherche Scientifique (CNRS), Université Paris-Saclay, Orsay, 91405, France
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7
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Katiyar AK, Hoang AT, Xu D, Hong J, Kim BJ, Ji S, Ahn JH. 2D Materials in Flexible Electronics: Recent Advances and Future Prospectives. Chem Rev 2024; 124:318-419. [PMID: 38055207 DOI: 10.1021/acs.chemrev.3c00302] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
Flexible electronics have recently gained considerable attention due to their potential to provide new and innovative solutions to a wide range of challenges in various electronic fields. These electronics require specific material properties and performance because they need to be integrated into a variety of surfaces or folded and rolled for newly formatted electronics. Two-dimensional (2D) materials have emerged as promising candidates for flexible electronics due to their unique mechanical, electrical, and optical properties, as well as their compatibility with other materials, enabling the creation of various flexible electronic devices. This article provides a comprehensive review of the progress made in developing flexible electronic devices using 2D materials. In addition, it highlights the key aspects of materials, scalable material production, and device fabrication processes for flexible applications, along with important examples of demonstrations that achieved breakthroughs in various flexible and wearable electronic applications. Finally, we discuss the opportunities, current challenges, potential solutions, and future investigative directions about this field.
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Affiliation(s)
- Ajit Kumar Katiyar
- School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Anh Tuan Hoang
- School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Duo Xu
- School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Juyeong Hong
- School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Beom Jin Kim
- School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Seunghyeon Ji
- School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Jong-Hyun Ahn
- School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, Republic of Korea
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8
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Pandey M, Ahuja R, Kumar R. Viscous fingering instabilities in spontaneously formed blisters of MoS 2 multilayers. NANOSCALE ADVANCES 2023; 5:6617-6625. [PMID: 38024300 PMCID: PMC10662142 DOI: 10.1039/d3na00563a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 10/05/2023] [Indexed: 12/01/2023]
Abstract
The viscous fingering in the Hele-Shaw cell can be suppressed by replacing the upper-bounding rigid plate with an elastic membrane. Recently, graphene multilayers while polymer-curing-induced blistering showed the dynamical evolution of viscous fingering patterns on a viscoelastic substrate due to their thickness-dependent elasticity. Under certain conditions, the elastic solid-based instability couples with the viscoelastic substrate-based instability. The mechanisms underlying such a coupling in the blisters of 2D materials and the dynamical evolution of the viscous fingering patterns underneath the blisters are yet to be addressed. Herein, we investigate the viscous fingering instabilities in spontaneously formed blisters of MoS2 multilayers, and provide thorough analytical and experimental insights for the elucidation of the dynamical evolution of the viscous fingering patterns and the coupled instabilities in the blisters. We also estimate the interfacial adhesion energy of the MoS2 flakes over a (poly)vinyl alcohol (PVA) substrate and the confinement pressure inside the MoS2 blisters using a conventional blister-test model. It is observed that the presence of instability gives rise to anomalies in the modeling of the blister test. The adhesion mechanical insights would be beneficial for fundamental research as well as practical applications of 2D material blisters in flexible optoelectronics.
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Affiliation(s)
- Mukesh Pandey
- Department of Physics, Indian Institute of Technology Ropar Rupnagar Punjab-140001 India
| | - Rajeev Ahuja
- Department of Physics, Indian Institute of Technology Ropar Rupnagar Punjab-140001 India
- Condensed Matter Theory Group, Department of Physics and Astronomy, Uppsala University Box 516 Uppsala-75120 Sweden
| | - Rakesh Kumar
- Department of Physics, Indian Institute of Technology Ropar Rupnagar Punjab-140001 India
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9
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Lemos JS, Blundo E, Polimeni A, Pimenta MA, Righi A. Exciton-Phonon Interactions in Strained Domes of Monolayer MoS 2 Studied by Resonance Raman Spectroscopy. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2722. [PMID: 37836363 PMCID: PMC10574763 DOI: 10.3390/nano13192722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 09/26/2023] [Accepted: 10/01/2023] [Indexed: 10/15/2023]
Abstract
This work describes a resonance Raman study performed in the domes of monolayer MoS2 using 23 different laser excitation energies covering the visible and near-infrared (NIR) ranges. The multiple excitation results allowed us to investigate the exciton-phonon interactions of different phonons (A'1, E', and LA) with different excitonic optical transitions in biaxially strained monolayer MoS2. The analysis of the intensities of the two first-order peaks, A'1 and E', and the double-resonance 2LA Raman band as a function of the laser excitation furnished the values of the energies of the indirect exciton and the direct excitonic transitions in the strained MoS2 domes. It was noticed that the out-of-plane A'1 phonon mode is significantly enhanced only by the indirect exciton I and the C exciton, whereas the in-plane E' mode is only enhanced by the C exciton of the MoS2 dome, thus revealing the weak interaction of these phonons with the A and B excitons in the strained MoS2 domes. On the other hand, the 2LA Raman band is significantly enhanced at the indirect exciton I and by the A (or B) exciton but not enhanced by the C exciton, thus showing that the LA edge phonons that participate in the double-resonance process in MoS2 have a weak interaction with the C exciton.
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Affiliation(s)
- Jessica S. Lemos
- Departamento de Física, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, MG, Brazil;
| | - Elena Blundo
- Dipartimento di Fisica, Sapienza Università di Roma, 00185 Roma, Italy; (E.B.); (A.P.)
| | - Antonio Polimeni
- Dipartimento di Fisica, Sapienza Università di Roma, 00185 Roma, Italy; (E.B.); (A.P.)
| | - Marcos A. Pimenta
- Departamento de Física, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, MG, Brazil;
- Departamento de Física, Universidade Federal do Ouro Preto, Campus Universitário Morro do Cruzeiro, ICEB, Ouro Preto 35400-000, MG, Brazil
| | - Ariete Righi
- Departamento de Física, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, MG, Brazil;
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10
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Xu J, Liu W, Tang W, Liu G, Zhu Y, Yuan G, Wang L, Xi X, Gao L. Trapping Hydrogen Molecules between Perfect Graphene. NANO LETTERS 2023; 23:8203-8210. [PMID: 37584336 DOI: 10.1021/acs.nanolett.3c02321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/17/2023]
Abstract
There is a lack of deep understanding of hydrogen intercalation into graphite due to many challenges faced during characterization of the systems. Therefore, a suitable route to trap isolated hydrogen molecules (H2) between the perfect graphite lattices needs to be found. Here we realize the formation of hydrogen bubbles in graphite with controllable density, size, and layer number. We find that the molecular H2 cannot be diffused between nor escape from the defect-free graphene lattices, and it remains stable in the pressurized bubbles up to 400 °C. The internal pressure of H2 inside the bubbles is strongly temperature dependent, and it decreases as the temperature rises. The proton permeation rate can be estimated at a specific plasma power. The producing method of H2 bubbles offers a useful way for storing hydrogen in layered materials, and these materials provide a prospective research platform for studying nontrivial quantum effects in confined H2.
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Affiliation(s)
- Jie Xu
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory for Nanotechnology, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Weilin Liu
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory for Nanotechnology, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Wenna Tang
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory for Nanotechnology, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Gan Liu
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory for Nanotechnology, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Yujian Zhu
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory for Nanotechnology, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Guowen Yuan
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory for Nanotechnology, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Lei Wang
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory for Nanotechnology, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Xiaoxiang Xi
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory for Nanotechnology, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Libo Gao
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory for Nanotechnology, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
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11
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Korneva M, Zhilyaev P. Solid-liquid phase transition inside van der Waals nanobubbles: an atomistic perspective. Phys Chem Chem Phys 2023. [PMID: 37432424 DOI: 10.1039/d3cp01285a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/12/2023]
Abstract
The liquid-solid phase transition during the confinement of a van der Waals bubble is studied using molecular dynamics simulations. In particular, argon is considered inside a graphene bubble, where the outer membrane is a sheet of graphene, and the substrate is atomically flat graphite. A methodology to avoid metastable states of argon is developed and implemented to derive a melting curve of trapped argon. It is found that in the confinement, the melting curve of argon shifts toward higher temperatures, and the temperature shift is about 10-30 K. The ratio of the height to the radius of the GNB (H/R) decreases with increasing temperature. It also most likely undergoes an abrupt change through the liquid-crystal phase transition. The semi-liquid state of argon was detected in the transition region. At this state, the argon structure stays layered, but the atoms travel distances of several lattice constants.
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Affiliation(s)
- Mariia Korneva
- Center for Materials Technologies, Skolkovo Institute of Science and Technology, Skolkovo Innovation Center, Building 3, Moscow, 143026, Russia.
| | - Petr Zhilyaev
- Center for Materials Technologies, Skolkovo Institute of Science and Technology, Skolkovo Innovation Center, Building 3, Moscow, 143026, Russia.
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12
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Deng M, Wang X, Xu X, Cui A, Jiang K, Zhang J, Zhu L, Shang L, Li Y, Hu Z, Chu J. Directly measuring flexoelectric coefficients μ11 of the van der Waals materials. MATERIALS HORIZONS 2023; 10:1309-1323. [PMID: 36692359 DOI: 10.1039/d2mh00984f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Flexoelectricity originates from the electromechanical coupling interaction between strain gradient and polarization, broadly applied in developing electromechanical and energy devices. However, the study of quantifying the longitudinal flexoelectric coefficient (μ11) which is important for the application of atomic-scale two-dimensional (2D) materials is still in a slow-moving stage, owing to the technical challenges. Based on the free-standing suspension structure, this paper proposes a widely applicable method and a mensurable formula for determining the μ11 constant of layer-dependent 2D materials with high precision. A combination of in situ micro-Raman spectroscopy and piezoresponse force microscopy (PFM) imaging was used to quantify the strain distribution and effective out-of-plane electromechanical coupling, respectively, for μ11 constant calculation. The μ11 constants and their physical correlation with the variable mechanical conditions of naturally bent structures have been obtained extensively for the representative mono-to-few layered MX2 family (M = W and Mo; X = S and Se), and the result is perfectly consistent with the estimated order-of-magnitude of the μ11 value (about 0.065) of monolayer MoS2. The quantification of the flexoelectric constant in this work not only promotes the understanding of mechanical and electromechanical properties in van der Waals materials, but also paves the way for developing novel 2D nano-energy devices and mechanical transducers based on flexoelectric effects.
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Affiliation(s)
- Menghan Deng
- Technical Center for Multifunctional Magneto-Optical Spectroscopy (Shanghai), Engineering Research Center of Nanophotonics Advanced Instrument (Ministry of Education), Department of Physics, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China.
| | - Xiang Wang
- Technical Center for Multifunctional Magneto-Optical Spectroscopy (Shanghai), Engineering Research Center of Nanophotonics Advanced Instrument (Ministry of Education), Department of Physics, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China.
| | - Xionghu Xu
- Technical Center for Multifunctional Magneto-Optical Spectroscopy (Shanghai), Engineering Research Center of Nanophotonics Advanced Instrument (Ministry of Education), Department of Physics, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China.
| | - Anyang Cui
- Technical Center for Multifunctional Magneto-Optical Spectroscopy (Shanghai), Engineering Research Center of Nanophotonics Advanced Instrument (Ministry of Education), Department of Physics, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China.
| | - Kai Jiang
- Technical Center for Multifunctional Magneto-Optical Spectroscopy (Shanghai), Engineering Research Center of Nanophotonics Advanced Instrument (Ministry of Education), Department of Physics, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China.
| | - Jinzhong Zhang
- Technical Center for Multifunctional Magneto-Optical Spectroscopy (Shanghai), Engineering Research Center of Nanophotonics Advanced Instrument (Ministry of Education), Department of Physics, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China.
| | - Liangqing Zhu
- Technical Center for Multifunctional Magneto-Optical Spectroscopy (Shanghai), Engineering Research Center of Nanophotonics Advanced Instrument (Ministry of Education), Department of Physics, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China.
| | - Liyan Shang
- Technical Center for Multifunctional Magneto-Optical Spectroscopy (Shanghai), Engineering Research Center of Nanophotonics Advanced Instrument (Ministry of Education), Department of Physics, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China.
| | - Yawei Li
- Technical Center for Multifunctional Magneto-Optical Spectroscopy (Shanghai), Engineering Research Center of Nanophotonics Advanced Instrument (Ministry of Education), Department of Physics, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China.
| | - Zhigao Hu
- Technical Center for Multifunctional Magneto-Optical Spectroscopy (Shanghai), Engineering Research Center of Nanophotonics Advanced Instrument (Ministry of Education), Department of Physics, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China.
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Junhao Chu
- Technical Center for Multifunctional Magneto-Optical Spectroscopy (Shanghai), Engineering Research Center of Nanophotonics Advanced Instrument (Ministry of Education), Department of Physics, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China.
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
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13
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Liu B, Yildirim T, Lü T, Blundo E, Wang L, Jiang L, Zou H, Zhang L, Zhao H, Yin Z, Tian F, Polimeni A, Lu Y. Variant Plateau's law in atomically thin transition metal dichalcogenide dome networks. Nat Commun 2023; 14:1050. [PMID: 36828812 PMCID: PMC9958105 DOI: 10.1038/s41467-023-36565-2] [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: 09/01/2022] [Accepted: 02/07/2023] [Indexed: 02/26/2023] Open
Abstract
Since its fundamental inception from soap bubbles, Plateau's law has sparked extensive research in equilibrated states. However, most studies primarily relied on liquids, foams or cellular structures, whereas its applicability has yet to be explored in nano-scale solid films. Here, we observed a variant Plateau's law in networks of atomically thin domes made of solid two-dimensional (2D) transition metal dichalcogenides (TMDs). Discrete layer-dependent van der Waals (vdWs) interaction energies were experimentally and theoretically obtained for domes protruding in different TMD layers. Significant surface tension differences from layer-dependent vdWs interaction energies manifest in a variant of this fundamental law. The equivalent surface tension ranges from 2.4 to 3.6 N/m, around two orders of magnitude greater than conventional liquid films, enabling domes to sustain high gas pressure and exist in a fundamentally variant nature for several years. Our findings pave the way towards exploring variant discretised states with applications in opto-electro-mechanical devices.
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Affiliation(s)
- Boqing Liu
- grid.1001.00000 0001 2180 7477School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601 Australia
| | - Tanju Yildirim
- grid.21941.3f0000 0001 0789 6880Center for Functional Sensor & Actuator (CFSN), Research Center for Functional Materials, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 Japan
| | - Tieyu Lü
- grid.12955.3a0000 0001 2264 7233Department of Physics and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen, 361005 China
| | - Elena Blundo
- grid.7841.aDipartimento di Fisica Sapienza Università di Roma, 00185 Roma, Italy
| | - Li Wang
- grid.1005.40000 0004 4902 0432School of Engineering and Information Technology, University of New South Wales, Canberra, ACT 2600 Australia
| | - Lixue Jiang
- grid.1022.10000 0004 0437 5432Centre for Catalysis and Clean Energy, Gold Coast Campus, Griffith University, Queensland, 4222 Australia
| | - Hongshuai Zou
- grid.64924.3d0000 0004 1760 5735State Key Laboratory of Integrated Optoelectronics, School of Materials Science and Engineering, and Jilin Provincial International Cooperation Key Laboratory of High-Efficiency Clean Energy Materials, Jilin University, Changchun, 130012 China
| | - Lijun Zhang
- grid.64924.3d0000 0004 1760 5735State Key Laboratory of Integrated Optoelectronics, School of Materials Science and Engineering, and Jilin Provincial International Cooperation Key Laboratory of High-Efficiency Clean Energy Materials, Jilin University, Changchun, 130012 China
| | - Huijun Zhao
- grid.1022.10000 0004 0437 5432Centre for Catalysis and Clean Energy, Gold Coast Campus, Griffith University, Queensland, 4222 Australia
| | - Zongyou Yin
- grid.1001.00000 0001 2180 7477Research School of Chemistry, College of Science, The Australian National University, Canberra, ACT 2601 Australia
| | - Fangbao Tian
- grid.1005.40000 0004 4902 0432School of Engineering and Information Technology, University of New South Wales, Canberra, ACT 2600 Australia
| | - Antonio Polimeni
- Dipartimento di Fisica Sapienza Università di Roma, 00185, Roma, Italy.
| | - Yuerui Lu
- School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601, Australia. .,ARC Centre of Excellence in Quantum Computation and Communication Technology ANU node, Canberra, ACT 2601, Australia.
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14
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Pandey M, Ahuja R, Kumar R. Hoop compression driven instabilities in spontaneously formed multilayer graphene blisters over a polymeric substrate. NANOTECHNOLOGY 2023; 34:175301. [PMID: 36584389 DOI: 10.1088/1361-6528/acaf33] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 12/29/2022] [Indexed: 06/17/2023]
Abstract
The blistering of elastic membranes is prone to elastic-solid as well as substrate-based mechanical instabilities. The solid-based instabilities have been well-explored in the mechanically indented blisters of elastic membranes over the rigid/solid substrates, but an integrated study illustrating the underlying mechanism for the onset of solid as well as substrate-based instabilities in the spontaneous blistering of a 2D material is still lacking in the literature. In this article, an extensive experimental as well as analytical analysis of the spontaneous blister-formation in the multilayer graphene (MLG) flakes over a polymeric substrate is reported, which elucidates the involved mechanism and the governing parameters behind the development of elastic-solid as well as viscoelastic-substrate based instabilities. Herein, a 'blister-collapse model' is proposed, which infers that the suppression of the hoop compression, resulting from the phase-transition of the confined matter, plays a crucial role in the development of the instabilities. The ratio of blister-height to flake-thickness is a direct consequence of the taper-angle of the MLG blister and the thickness-dependent elasticity of the upper-bounding MLG flake, which shows a significant impact on the growth-dynamics of the viscous fingering pattern (viscoelastic-substrate based instability) under the MLG blister.
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Affiliation(s)
- Mukesh Pandey
- Department of Physics, Indian Institute of Technology Ropar, Rupnagar, Punjab-140001, India
| | - Rajeev Ahuja
- Department of Physics, Indian Institute of Technology Ropar, Rupnagar, Punjab-140001, India
- Department of Physics and Astronomy, Uppsala University, Uppsala-75120, Sweden
| | - Rakesh Kumar
- Department of Physics, Indian Institute of Technology Ropar, Rupnagar, Punjab-140001, India
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15
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Rahman S, Sun X, Zhu Y, Lu Y. Extraordinary Phonon Displacement and Giant Resonance Raman Enhancement in WSe 2/WS 2 Moiré Heterostructures. ACS NANO 2022; 16:21505-21517. [PMID: 36441581 DOI: 10.1021/acsnano.2c10092] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Twisted van der Waals heterostructures are known to induce surprisingly diverse and intriguing phenomena, such as correlated electronic phase and unconventional optical properties. This can be realized by controlled rotation of adjacent atomic planes, which provides an uncommon way to manipulate inelastic light-matter interactions. Here, we discover an extraordinary blue shift of 5-6 wavenumbers for high-frequency phonon modes in WS2/WSe2 twisted heterobilayers, captured meticulously using Raman spectroscopy. Phonon spectra displace rapidly over a subtle change in interlayer twist angle owing to heterostrain and atomic reconstruction from the Moiré pattern. First-order linear coefficients of the phonon modes in twisted heterostructures are further found to increase largely compared to their monolayer counterpart and vary immensely with the twist angle. Exceptional and extravagant enhancement of up to 50-fold is observed in the Raman vibrational intensity at a specific twist angle; this is largely influenced by the resonance process derived from a simple critical twist angle model. In addition, we depict how the resonance can be modulated by changing the thermal conditions and also the stacking angle. Therefore, our work further highlights the twist-driven phonon dynamics in pristine two-dimensional heterostructures, adding vital insight into Moiré physics and promoting comprehensive understanding of structural and optical properties in Moiré superlattices.
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Affiliation(s)
- Sharidya Rahman
- School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT2601, Australia
| | - Xueqian Sun
- School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT2601, Australia
| | - Yi Zhu
- Department of Engineering, University of Cambridge, CambridgeCB3 0FA, United Kingdom
| | - Yuerui Lu
- School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT2601, Australia
- Centre for Quantum Computation and Communication Technology, School of Engineering, The Australian National University, Canberra, ACT2601, Australia
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16
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Rahman S, Yildirim T, Tebyetekerwa M, Khan AR, Lu Y. Extraordinary Nonlinear Optical Interaction from Strained Nanostructures in van der Waals CuInP 2S 6. ACS NANO 2022; 16:13959-13968. [PMID: 35980379 DOI: 10.1021/acsnano.2c03294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Local strain engineering and structural modification of 2D materials furnish benevolent control over their optoelectronic properties and provide an exciting approach to tune light-matter interaction in layered materials. Application of strain at the nanoscale is typically obtained through permanently deformed nanostructures such as nanowrinkles, which yield large band gap modulation, photoluminescence enhancement, and surface potential. Ultrathin transition metal dichalcogenides (TMDs) have been greatly analyzed for such purposes. Herein, we extend strain-induced nanoengineering to an emerging 2D material, CuInP2S6 (CIPS), and visualize extraordinary control over nonlinear light-matter interaction. Wrinkle nanostructures exhibit ∼160-fold enhancement in second harmonic generation (SHG) compared to unstrained regions, which is additionally influenced by a change in the dielectric environment. The SHG enhancement was significantly modulated by the percentage of applied strain which was numerically estimated. Furthermore, polarization-dependent SHG revealed quenching and enhancement in the parallel and perpendicular directions, respectively, due to the direction of the compressive vector. Our work provides an important advancement in controlling optoelectronic properties beyond TMDs for imminent applications in flexible electronics.
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Affiliation(s)
- Sharidya Rahman
- School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Tanju Yildirim
- Center for Functional Sensor and Actuator, Research Center for Functional Materials, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Mike Tebyetekerwa
- Dow Centre for Sustainable Engineering Innovation, School of Chemical Engineering, University of Queensland, St Lucia, Queensland 4072, Australia
| | - Ahmed Raza Khan
- School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Yuerui Lu
- School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, Australian Capital Territory 2601, Australia
- Centre for Quantum Computation and Communication Technology, School of Engineering, The Australian National University, Canberra, Australian Capital Territory 2601, Australia
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17
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Sharma A, Zhu Y, Halbich R, Sun X, Zhang L, Wang B, Lu Y. Engineering the Dynamics and Transport of Excitons, Trions, and Biexcitons in Monolayer WS 2. ACS APPLIED MATERIALS & INTERFACES 2022; 14:41165-41177. [PMID: 36048513 DOI: 10.1021/acsami.2c08199] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The study of transport and diffusion dynamics of quasi-particles such as excitons, trions, and biexcitons in two-dimensional (2D) semiconductors has opened avenues for their application in high-speed excitonic and optoelectronic devices. However, long-range transport and fast diffusion of these quasi-particles have not been reported for 2D systems such as transition metal dichalcogenides (TMDCs). The reported diffusion coefficients from TMDCs are low, limiting their use in high-speed excitonic devices and other optoelectronic applications. Here, we report the highest exciton diffusion coefficient value in monolayer WS2 achieved via engineering the radiative lifetime and diffusion lengths using static back-gate voltage and substrate engineering. Electrostatic doping is observed to modulate the radiative lifetime and in turn the diffusion coefficient of excitons by ∼three times at room temperature. By combining electrostatic doping and substrate engineering, we push the diffusion coefficient to an extremely high value of 86.5 cm2/s, which has not been reported before in TMDCs and is even higher than the values in some 1D systems. At low temperatures, we further report the control of dynamic and spatial diffusion of excitons, trions, and biexcitons from WS2. The electrostatic control of dynamics and transport of these quasi-particles in monolayers establishes monolayer TMDCs as ideal candidates for high-speed excitonic circuits, optoelectronic, and photonic device applications.
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Affiliation(s)
- Ankur Sharma
- School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601, Australia
| | - Yi Zhu
- School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601, Australia
- Department of Engineering, University of Cambridge, Cambridge CB3 0FA, United Kingdom
| | - Robert Halbich
- School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601, Australia
| | - Xueqian Sun
- School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601, Australia
| | - Linglong Zhang
- School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601, Australia
| | - Bowen Wang
- School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601, Australia
| | - Yuerui Lu
- School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601, Australia
- ARC Centre of Excellence in Quantum Computation and Communication Technology ANU Node, Canberra, ACT 2601, Australia
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18
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Lee HY, Sarkar S, Reidy K, Kumar A, Klein J, Watanabe K, Taniguchi T, LeBeau JM, Ross FM, Gradečak S. Strong and Localized Luminescence from Interface Bubbles Between Stacked hBN Multilayers. Nat Commun 2022; 13:5000. [PMID: 36008409 PMCID: PMC9411575 DOI: 10.1038/s41467-022-32708-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 08/12/2022] [Indexed: 11/09/2022] Open
Abstract
Extraordinary optoelectronic properties of van der Waals (vdW) heterostructures can be tuned via strain caused by mechanical deformation. Here, we demonstrate strong and localized luminescence in the ultraviolet region from interface bubbles between stacked multilayers of hexagonal boron nitride (hBN). Compared to bubbles in stacked monolayers, bubbles formed by stacking vdW multilayers show distinct mechanical behavior. We use this behavior to elucidate radius- and thickness-dependent bubble geometry and the resulting strain across the bubble, from which we establish the thickness-dependent bending rigidity of hBN multilayers. We then utilize the polymeric material confined within the bubbles to modify the bubble geometry under electron beam irradiation, resulting in strong luminescence and formation of optical standing waves. Our results open a route to design and modulate microscopic-scale optical cavities via strain engineering in vdW materials, which we suggest will be relevant to both fundamental mechanical studies and optoelectronic applications.
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Affiliation(s)
- Hae Yeon Lee
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA, 02141, USA
| | - Soumya Sarkar
- Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, 117575, Singapore, Singapore
| | - Kate Reidy
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA, 02141, USA
| | - Abinash Kumar
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA, 02141, USA
| | - Julian Klein
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA, 02141, USA
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - James M LeBeau
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA, 02141, USA
| | - Frances M Ross
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA, 02141, USA
| | - Silvija Gradečak
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA, 02141, USA. .,Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, 117575, Singapore, Singapore.
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19
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Blundo E, Junior PEF, Surrente A, Pettinari G, Prosnikov MA, Olkowska-Pucko K, Zollner K, Woźniak T, Chaves A, Kazimierczuk T, Felici M, Babiński A, Molas MR, Christianen PCM, Fabian J, Polimeni A. Strain-Induced Exciton Hybridization in WS_{2} Monolayers Unveiled by Zeeman-Splitting Measurements. PHYSICAL REVIEW LETTERS 2022; 129:067402. [PMID: 36018658 DOI: 10.1103/physrevlett.129.067402] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 06/09/2022] [Indexed: 06/15/2023]
Abstract
Mechanical deformations and ensuing strain are routinely exploited to tune the band gap energy and to enhance the functionalities of two-dimensional crystals. In this Letter, we show that strain leads also to a strong modification of the exciton magnetic moment in WS_{2} monolayers. Zeeman-splitting measurements under magnetic fields up to 28.5 T were performed on single, one-layer-thick WS_{2} microbubbles. The strain of the bubbles causes a hybridization of k-space direct and indirect excitons resulting in a sizable decrease in the modulus of the g factor of the ground-state exciton. These findings indicate that strain may have major effects on the way the valley number of excitons can be used to process binary information in two-dimensional crystals.
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Affiliation(s)
- Elena Blundo
- Physics Department, Sapienza University of Rome, 00185 Rome, Italy
| | - Paulo E Faria Junior
- Institute for Theoretical Physics, University of Regensburg, 93040 Regensburg, Germany
| | - Alessandro Surrente
- Physics Department, Sapienza University of Rome, 00185 Rome, Italy
- Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, 50-370 Wrocław, Poland
| | - Giorgio Pettinari
- Institute for Photonics and Nanotechnologies, National Research Council, 00156 Rome, Italy
| | - Mikhail A Prosnikov
- High Field Magnet Laboratory, HFML-EMFL, Radboud University, 6525 ED Nijmegen, The Netherlands
| | - Katarzyna Olkowska-Pucko
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - Klaus Zollner
- Institute for Theoretical Physics, University of Regensburg, 93040 Regensburg, Germany
| | - Tomasz Woźniak
- Department of Semiconductor Materials Engineering, Wrocław University of Science and Technology, 50-370 Wrocław, Poland
| | - Andrey Chaves
- Departamento de Fisica, Universidade Federal do Ceará, 60455-900 Fortaleza, Ceará, Brazil
- Department of Physics, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerpen, Belgium
| | - Tomasz Kazimierczuk
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - Marco Felici
- Physics Department, Sapienza University of Rome, 00185 Rome, Italy
| | - 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
| | - Peter C M Christianen
- High Field Magnet Laboratory, HFML-EMFL, Radboud University, 6525 ED Nijmegen, The Netherlands
| | - Jaroslav Fabian
- Institute for Theoretical Physics, University of Regensburg, 93040 Regensburg, Germany
| | - Antonio Polimeni
- Physics Department, Sapienza University of Rome, 00185 Rome, Italy
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20
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Felton J, Blundo E, Kudrynskyi Z, Ling S, Bradford J, Pettinari G, Cooper T, Wadge M, Kovalyuk Z, Polimeni A, Beton P, Grant D, Walker G, Patanè A. Hydrogen-Induced Conversion of SnS 2 into SnS or Sn: A Route to Create SnS 2 /SnS Heterostructures. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2202661. [PMID: 35863913 DOI: 10.1002/smll.202202661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 06/22/2022] [Indexed: 06/15/2023]
Abstract
The family of van der Waals (vdW) materials is large and diverse with applications ranging from electronics and optoelectronics to catalysis and chemical storage. However, despite intensive research, there remains significant knowledge-gaps pertaining to their properties and interactions. One such gap is the interaction between these materials and hydrogen, a potentially vital future energy vector and ubiquitous processing gas in the semiconductor industry. This work reports on the interaction of hydrogen with the vdW semiconductor SnS2 , where molecular hydrogen (H2 ) and H-ions induce a controlled chemical conversion into semiconducting-SnS or to β-Sn. This hydrogen-driven reaction is facilitated by the different oxidation states of Sn and is successfully applied to form SnS2 /SnS heterostructures with uniform layers, atomically flat interfaces and well-aligned crystallographic axes. This approach is scalable and offers a route for engineering materials at the nanoscale for semiconductor technologies based on the earth-abundant elements Sn and S, a promising result for a wide range of potential applications.
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Affiliation(s)
- James Felton
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Elena Blundo
- Dipartimento di Fisica, Sapienza Universitä di Roma, Roma, 00185, Italy
| | - Zakhar Kudrynskyi
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Sanliang Ling
- Advanced Materials Research Group, Faculty of Engineering, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Jonathan Bradford
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Giorgio Pettinari
- Institute for Photonics and Nanotechnologies (CNR-IFN), National Research Council, Rome, 00156, Italy
| | - Timothy Cooper
- Advanced Materials Research Group, Faculty of Engineering, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Matthew Wadge
- Advanced Materials Research Group, Faculty of Engineering, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Zakhar Kovalyuk
- Institute for Problems of Materials Science, National Academy of Sciences of Ukraine, Chernivtsi Branch, Chernivtsi, 58001, Ukraine
| | - Antonio Polimeni
- Dipartimento di Fisica, Sapienza Universitä di Roma, Roma, 00185, Italy
| | - Peter Beton
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - David Grant
- Advanced Materials Research Group, Faculty of Engineering, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Gavin Walker
- Advanced Materials Research Group, Faculty of Engineering, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Amalia Patanè
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
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21
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Spirito D, Barra-Burillo M, Calavalle F, Manganelli CL, Gobbi M, Hillenbrand R, Casanova F, Hueso LE, Martín-García B. Tailoring Photoluminescence by Strain-Engineering in Layered Perovskite Flakes. NANO LETTERS 2022; 22:4153-4160. [PMID: 35435688 DOI: 10.1021/acs.nanolett.2c00909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Strain is an effective strategy to modulate the optoelectronic properties of 2D materials, but it has been almost unexplored in layered hybrid organic-inorganic metal halide perovskites (HOIPs) due to their complex band structure and mechanical properties. Here, we investigate the temperature-dependent microphotoluminescence (PL) of 2D (C6H5CH2CH2NH3)2Cs3Pb4Br13 HOIP subject to biaxial strain induced by a SiO2 ring platform on which flakes are placed by viscoelastic stamping. At 80 K, we found that a strain of <1% can change the PL emission from a single peak (unstrained) to three well-resolved peaks. Supported by micro-Raman spectroscopy, we show that the thermomechanically generated strain modulates the bandgap due to changes in the octahedral tilting and lattice expansion. Mechanical simulations demonstrate the coexistence of tensile and compressive strain along the flake. The observed PL peaks add an interesting feature to the rich phenomenology of photoluminescence in 2D HOIPs, which can be exploited in tailored sensing and optoelectronic devices.
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Affiliation(s)
- Davide Spirito
- IHP-Leibniz-Institut für innovative Mikroelektronik, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany
| | - María Barra-Burillo
- CIC nanoGUNE BRTA, Tolosa Hiribidea, 76, 20018 Donostia-San Sebastián, Basque Country, Spain
| | - Francesco Calavalle
- CIC nanoGUNE BRTA, Tolosa Hiribidea, 76, 20018 Donostia-San Sebastián, Basque Country, Spain
| | - Costanza Lucia Manganelli
- IHP-Leibniz-Institut für innovative Mikroelektronik, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany
| | - Marco Gobbi
- CIC nanoGUNE BRTA, Tolosa Hiribidea, 76, 20018 Donostia-San Sebastián, Basque Country, Spain
- IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Basque Country, Spain
- Materials Physics Center CSIC-UPV/EHU, 20018 Donostia-San Sebastián, Spain
| | - Rainer Hillenbrand
- CIC nanoGUNE BRTA, Tolosa Hiribidea, 76, 20018 Donostia-San Sebastián, Basque Country, Spain
- IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Basque Country, Spain
- Department of Electricity and Electronics, UPV/EHU, 20018 Donostia-San Sebastián, Spain
| | - Fèlix Casanova
- CIC nanoGUNE BRTA, Tolosa Hiribidea, 76, 20018 Donostia-San Sebastián, Basque Country, Spain
- IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Basque Country, Spain
| | - Luis E Hueso
- CIC nanoGUNE BRTA, Tolosa Hiribidea, 76, 20018 Donostia-San Sebastián, Basque Country, Spain
- IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Basque Country, Spain
| | - Beatriz Martín-García
- CIC nanoGUNE BRTA, Tolosa Hiribidea, 76, 20018 Donostia-San Sebastián, Basque Country, Spain
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22
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Oliva R, Wozniak T, Faria PE, Dybala F, Kopaczek J, Fabian J, Scharoch P, Kudrawiec R. Strong Substrate Strain Effects in Multilayered WS 2 Revealed by High-Pressure Optical Measurements. ACS APPLIED MATERIALS & INTERFACES 2022; 14:19857-19868. [PMID: 35442641 PMCID: PMC9073841 DOI: 10.1021/acsami.2c01726] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 03/29/2022] [Indexed: 06/14/2023]
Abstract
The optical properties of two-dimensional materials can be effectively tuned by strain induced from a deformable substrate. In the present work we combine first-principles calculations based on density functional theory and the effective Bethe-Salpeter equation with high-pressure optical measurements to thoroughly describe the effect of strain and dielectric environment onto the electronic band structure and optical properties of a few-layered transition-metal dichalcogenide. Our results show that WS2 remains fully adhered to the substrate at least up to a -0.6% in-plane compressive strain for a wide range of substrate materials. We provide a useful model to describe effect of strain on the optical gap energy. The corresponding experimentally determined out-of-plane and in-plane stress gauge factors for WS2 monolayers are -8 and 24 meV/GPa, respectively. The exceptionally large in-plane gauge factor confirms transition metal dichalcogenides as very promising candidates for flexible functionalities. Finally, we discuss the pressure evolution of an optical transition closely lying to the A exciton for bulk WS2 as well as the direct-to-indirect transition of the monolayer upon compression.
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Affiliation(s)
- Robert Oliva
- Department
of Semiconductor Materials Engineering, Faculty of Fundamental Problems
of Technology, Wroclaw University of Science
and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Tomasz Wozniak
- Department
of Semiconductor Materials Engineering, Faculty of Fundamental Problems
of Technology, Wroclaw University of Science
and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Paulo E. Faria
- Department
of Physics, University of Regensburg, 93040 Regensburg, Germany
| | - Filip Dybala
- Department
of Semiconductor Materials Engineering, Faculty of Fundamental Problems
of Technology, Wroclaw University of Science
and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Jan Kopaczek
- Department
of Semiconductor Materials Engineering, Faculty of Fundamental Problems
of Technology, Wroclaw University of Science
and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Jaroslav Fabian
- Department
of Physics, University of Regensburg, 93040 Regensburg, Germany
| | - Paweł Scharoch
- Department
of Semiconductor Materials Engineering, Faculty of Fundamental Problems
of Technology, Wroclaw University of Science
and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Robert Kudrawiec
- Department
of Semiconductor Materials Engineering, Faculty of Fundamental Problems
of Technology, Wroclaw University of Science
and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
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23
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Covre FS, Faria PE, Gordo VO, de Brito CS, Zhumagulov YV, Teodoro MD, Couto ODD, Misoguti L, Pratavieira S, Andrade MB, Christianen PCM, Fabian J, Withers F, Galvão Gobato Y. Revealing the impact of strain in the optical properties of bubbles in monolayer MoSe 2. NANOSCALE 2022; 14:5758-5768. [PMID: 35348558 DOI: 10.1039/d2nr00315e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Strain plays an important role for the optical properties of monolayer transition metal dichalcogenides (TMDCs). Here, we investigate strain effects in a monolayer MoSe2 sample with a large bubble region using μ-Raman, second harmonic generation (SHG), μ-photoluminescence and magneto μ-photoluminescence at low temperature. Remarkably, our results reveal the presence of a non-uniform strain field and the observation of emission peaks at lower energies which are the signatures of exciton and trion quasiparticles red-shifted by strain effects in the bubble region, in agreement with our theoretical predictions. Furthermore, we have observed that the emission in the strained region decreases the trion binding energy and enhances the valley g-factors as compared to non-strained regions. Considering uniform biaxial strain effects within the unit cell of the TMDC monolayer (ML), our first principles calculations predict the observed enhancement of the exciton valley Zeeman effect. In addition, our results suggest that the exciton-trion fine structure plays an important role for the optical properties of strained TMDC ML. In summary, our study provides fundamental insights on the behaviour of excitons and trions in strained monolayer MoSe2 which are particularly relevant to properly characterize and understand the fine structure of excitonic complexes in strained TMDC systems/devices.
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Affiliation(s)
- F S Covre
- Departamento de Física, Universidade Federal de São Carlos, 13565-905, São Carlos, SP, Brazil.
| | - P E Faria
- Institute for Theoretical Physics, University of Regensburg, 93040 Regensburg, Germany
| | - V O Gordo
- Instituto de Física "Gleb Wataghin", Universidade Estadual de Campinas, 13083-859, Campinas, São Paulo, Brazil
| | - C Serati de Brito
- Departamento de Física, Universidade Federal de São Carlos, 13565-905, São Carlos, SP, Brazil.
| | - Y V Zhumagulov
- Institute for Theoretical Physics, University of Regensburg, 93040 Regensburg, Germany
| | - M D Teodoro
- Departamento de Física, Universidade Federal de São Carlos, 13565-905, São Carlos, SP, Brazil.
| | - O D D Couto
- Instituto de Física "Gleb Wataghin", Universidade Estadual de Campinas, 13083-859, Campinas, São Paulo, Brazil
| | - L Misoguti
- Instituto de Física de São Carlos - Universidade de São Paulo, CEP 13566-590, São Carlos, São Paulo, Brazil
| | - S Pratavieira
- Instituto de Física de São Carlos - Universidade de São Paulo, CEP 13566-590, São Carlos, São Paulo, Brazil
| | - M B Andrade
- Instituto de Física de São Carlos - Universidade de São Paulo, CEP 13566-590, São Carlos, São Paulo, Brazil
| | - P C M Christianen
- High Field Magnet Laboratory (HFML - EMFL), Radboud University, 6525 ED Nijmegen, The Netherlands
| | - J Fabian
- Institute for Theoretical Physics, University of Regensburg, 93040 Regensburg, Germany
| | - F Withers
- College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter EX4 4QF, UK
| | - Y Galvão Gobato
- Departamento de Física, Universidade Federal de São Carlos, 13565-905, São Carlos, SP, Brazil.
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24
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Kovalchuk S, Kirchhof JN, Bolotin KI, Harats MG. Non‐Uniform Strain Engineering of 2D Materials. Isr J Chem 2022. [DOI: 10.1002/ijch.202100115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
| | - Jan. N. Kirchhof
- Department of Physics Freie University Berlin 14195 Berlin Germany
| | | | - Moshe G. Harats
- Department of Materials Engineering Ben Gurion University < postCode/>84105 Be'er Sheva Israel
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25
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Blundo E, Surrente A, Spirito D, Pettinari G, Yildirim T, Chavarin CA, Baldassarre L, Felici M, Polimeni A. Vibrational Properties in Highly Strained Hexagonal Boron Nitride Bubbles. NANO LETTERS 2022; 22:1525-1533. [PMID: 35107287 PMCID: PMC8880391 DOI: 10.1021/acs.nanolett.1c04197] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 01/25/2022] [Indexed: 05/24/2023]
Abstract
Hexagonal boron nitride (hBN) is widely used as a protective layer for few-atom-thick crystals and heterostructures (HSs), and it hosts quantum emitters working up to room temperature. In both instances, strain is expected to play an important role, either as an unavoidable presence in the HS fabrication or as a tool to tune the quantum emitter electronic properties. Addressing the role of strain and exploiting its tuning potentiality require the development of efficient methods to control it and of reliable tools to quantify it. Here we present a technique based on hydrogen irradiation to induce the formation of wrinkles and bubbles in hBN, resulting in remarkably high strains of ∼2%. By combining infrared (IR) near-field scanning optical microscopy and micro-Raman measurements with numerical calculations, we characterize the response to strain for both IR-active and Raman-active modes, revealing the potential of the vibrational properties of hBN as highly sensitive strain probes.
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Affiliation(s)
- Elena Blundo
- Physics
Department, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy
| | - Alessandro Surrente
- Physics
Department, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy
- Department
of Experimental Physics, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wroclaw 50-370, Poland
| | - Davide Spirito
- IHP-Leibniz
Institut fur Innovative Mikroelektronik, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany
| | - Giorgio Pettinari
- Institute
for Photonics and Nanotechnologies (CNR-IFN), National Research Council, 00156 Rome, Italy
| | - Tanju Yildirim
- Center
for Functional Sensor & Actuator (CFSN), National Institute for Materials Science (NIMS), Tsukuba, Ibaraki 305-0044, Japan
| | - Carlos Alvarado Chavarin
- IHP-Leibniz
Institut fur Innovative Mikroelektronik, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany
| | - Leonetta Baldassarre
- Physics
Department, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy
- IHP-Leibniz
Institut fur Innovative Mikroelektronik, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany
| | - Marco Felici
- Physics
Department, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy
| | - Antonio Polimeni
- Physics
Department, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy
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26
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Abstract
Due to unprecedented application prospects such as high-density and low-power multistate storage, spintronics and nanoelectronics, two-dimensional (2D) multiferroics, coupled with at least two ferroic orders, have gotten a lot of interest in recent years. Multiple functions can be achieved in 2D multiferroics via coupling phenomena such as magnetoelectricity, piezoelectricity, and magnetoelasticity, which offers technical support for the creation of multifunctional devices. The research progress of 2D ferromagnetic-ferroelectric multiferroic materials, ferroelectric-ferroelastic multiferroic materials, and ferromagnetic-ferroelastic materials in recent years is reviewed in this paper. The categorization of 2D multiferroics is explored in terms of the multiple sources of ferroelectricity. The top-down approaches and the bottom-up methods used to fabricate 2D multiferroics materials are introduced. Finally, the authors outline potential research prospects and application scenarios for 2D multiferroic materials.
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Affiliation(s)
- Yunye Gao
- School of Engineering, College of Engineering and Computer Science, the Australian National University, Canberra, Australian Capital Territory 2601, Australia.
| | - Mingyuan Gao
- School of Engineering, College of Engineering and Computer Science, the Australian National University, Canberra, Australian Capital Territory 2601, Australia.
- College of Engineering and Technology, Southwest University, Chongqing 400716, China
| | - Yuerui Lu
- School of Engineering, College of Engineering and Computer Science, the Australian National University, Canberra, Australian Capital Territory 2601, Australia.
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27
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Rahman S, Torres JF, Khan AR, Lu Y. Recent Developments in van der Waals Antiferromagnetic 2D Materials: Synthesis, Characterization, and Device Implementation. ACS NANO 2021; 15:17175-17213. [PMID: 34779616 DOI: 10.1021/acsnano.1c06864] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Magnetism in two dimensions is one of the most intriguing and alluring phenomena in condensed matter physics. Atomically thin 2D materials have emerged as a promising platform for exploring magnetic properties, leading to the development of essential technologies such as supercomputing and data storage. Arising from spin and charge dynamics in elementary particles, magnetism has also unraveled promising advances in spintronic devices and spin-dependent optoelectronics and photonics. Recently, antiferromagnetism in 2D materials has received extensive attention, leading to significant advances in their understanding and emerging applications; such materials have zero net magnetic moment yet are internally magnetic. Several theoretical and experimental approaches have been proposed to probe, characterize, and modulate the magnetic states efficiently in such systems. This Review presents the latest developments and current status for tuning the magnetic properties in distinct 2D van der Waals antiferromagnets. Various state-of-the-art optical techniques deployed to investigate magnetic textures and dynamics are discussed. Furthermore, device concepts based on antiferromagnetic spintronics are scrutinized. We conclude with remarks on related challenges and technological outlook in this rapidly expanding field.
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Affiliation(s)
- Sharidya Rahman
- School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601, Australia
| | - Juan F Torres
- School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601, Australia
| | - Ahmed Raza Khan
- School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601, Australia
| | - Yuerui Lu
- School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601, Australia
- ARC Centre for Quantum Computation and Communication Technology, Department of Quantum Science, Research School of Physics and Engineering, The Australian National University, Acton, ACT 2601, Australia
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), ANU node, Canberra, ACT 2601, Australia
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28
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Di Giorgio C, Blundo E, Pettinari G, Felici M, Polimeni A, Bobba F. Exceptional Elasticity of Microscale Constrained MoS 2 Domes. ACS APPLIED MATERIALS & INTERFACES 2021; 13:48228-48238. [PMID: 34592817 PMCID: PMC8517950 DOI: 10.1021/acsami.1c13293] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 09/21/2021] [Indexed: 05/31/2023]
Abstract
The outstanding mechanical performances of two-dimensional (2D) materials make them appealing for the emerging fields of flextronics and straintronics. However, their manufacturing and integration in 2D crystal-based devices rely on a thorough knowledge of their hardness, elasticity, and interface mechanics. Here, we investigate the elasticity of highly strained monolayer-thick MoS2 membranes, in the shape of micrometer-sized domes, by atomic force microscopy (AFM)-based nanoindentation experiments. A dome's crushing procedure is performed to induce a local re-adhesion of the dome's membrane to the bulk substrate under the AFM tip's load. It is worth noting that no breakage, damage, or variation in size and shape are recorded in 95% of the crushed domes upon unloading. Furthermore, such a procedure paves the way to address quantitatively the extent of the van der Waals interlayer interaction and adhesion of MoS2 by studying pull-in instabilities and hysteresis of the loading-unloading cycles. The fundamental role and advantage of using a superimposed dome's constraint are also discussed.
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Affiliation(s)
- Cinzia Di Giorgio
- Department
of Physics E.R. Caianiello, University of
Salerno, 84084 Fisciano, Italy
- INFN,
Sezione di Napoli, Gruppo Collegato di Salerno, Complesso Universitario di Monte S. Angelo, 80126 Napoli, Italy
| | - Elena Blundo
- Physics
Department, Sapienza University of Rome, 00185 Rome, Italy
| | - Giorgio Pettinari
- Institute
for Photonics and Nanotechnologies (CNR-IFN), National Research Council, 00156 Rome, Italy
| | - Marco Felici
- Physics
Department, Sapienza University of Rome, 00185 Rome, Italy
| | - Antonio Polimeni
- Physics
Department, Sapienza University of Rome, 00185 Rome, Italy
| | - Fabrizio Bobba
- Department
of Physics E.R. Caianiello, University of
Salerno, 84084 Fisciano, Italy
- INFN,
Sezione di Napoli, Gruppo Collegato di Salerno, Complesso Universitario di Monte S. Angelo, 80126 Napoli, Italy
- CNR-SPIN, 84084 Fisciano, SA, Italy
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29
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Blundo E, Yildirim T, Pettinari G, Polimeni A. Experimental Adhesion Energy in van der Waals Crystals and Heterostructures from Atomically Thin Bubbles. PHYSICAL REVIEW LETTERS 2021; 127:046101. [PMID: 34355951 DOI: 10.1103/physrevlett.127.046101] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 05/08/2021] [Accepted: 06/07/2021] [Indexed: 06/13/2023]
Abstract
The formation of gas-filled bubbles on the surface of van der Waals crystals provides an ideal platform whereby the interplay of the elastic parameters and interlayer forces can be suitably investigated. Here, we combine experimental and numerical efforts to study the morphology of the bubbles at equilibrium and highlight unexpected behaviors that contrast with the common assumptions. We exploit such observations to develop an accurate analytical model to describe the shape and strain of the bubbles and exploit it to measure the adhesion energy between a variety of van der Waals crystals, showing sizable material-dependent trends.
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Affiliation(s)
- Elena Blundo
- Physics Department, Sapienza University of Rome, 00185 Roma, Italy
| | - Tanju Yildirim
- Center for Functional Sensor and Actuator (CFSN), Research Center for Functional Materials, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Giorgio Pettinari
- Institute for Photonics and Nanotechnologies, National Research Council (CNR-IFN), 00156 Roma, Italy
| | - Antonio Polimeni
- Physics Department, Sapienza University of Rome, 00185 Roma, Italy
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30
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Pettinari G, Marotta G, Biccari F, Polimeni A, Felici M. Tailoring the optical properties of dilute nitride semiconductors at the nanometer scale. NANOTECHNOLOGY 2021; 32:185301. [PMID: 33503600 DOI: 10.1088/1361-6528/abe073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We report on the innovative approaches we developed for the fabrication of site-controlled semiconductor nanostructures [e.g. quantum dots (QDs), nanowires], based on the spatially selective incorporation and/or removal of hydrogen in dilute nitride semiconductor alloys [e.g. Ga(AsN) and (InGa)(AsN)]. In such systems, the formation of stable nitrogen-hydrogen complexes removes the effects nitrogen has on the alloy properties, which in turn paves the way to the direct engineering of the material's electronic-and, thus, optical-properties: not only the bandgap energy, but also the refractive index and the polarization properties of the system can indeed be tailored with high precision and in a reversible manner. Here, lithographic approaches and/or plasmon-assisted optical irradiation-coupled to the ultra-sharp diffusion profile of hydrogen in dilute nitrides-are employed to control the hydrogen implantation and/or removal process at a nanometer scale. This results in a highly deterministic control of the spatial and spectral properties of the fabricated nanostructures, eventually obtaining semiconductor nanowires with controlled polarization properties, as well as site-controlled QDs with an extremely high control on their spatial and spectral properties. The nanostructures fabricated with these techniques, whose optical properties have also been simulated by finite-element-method calculations, are naturally suited for a deterministic coupling in optical nanocavities (i.e. photonic crystal cavities and circular Bragg resonators) and are therefore of potential interest for emerging quantum technologies.
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Affiliation(s)
- Giorgio Pettinari
- Institute for Photonics and Nanotechnologies (CNR-IFN), National Research Council, Via Cineto Romano 42, I-00156 Roma, Italy
| | - Gianluca Marotta
- Department of Physics, Sapienza University of Rome, P.le A. Moro 5, I-00185 Roma, Italy
| | - Francesco Biccari
- Department of Physics and Astronomy, University of Florence, via Sansone 1, I-50019 Sesto Fiorentino (FI), Italy
| | - Antonio Polimeni
- Department of Physics, Sapienza University of Rome, P.le A. Moro 5, I-00185 Roma, Italy
| | - Marco Felici
- Department of Physics, Sapienza University of Rome, P.le A. Moro 5, I-00185 Roma, Italy
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31
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32
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Abdelnabi MMS, Blundo E, Betti MG, Cavoto G, Placidi E, Polimeni A, Ruocco A, Hu K, Ito Y, Mariani C. Towards free-standing graphane: atomic hydrogen and deuterium bonding to nano-porous graphene. NANOTECHNOLOGY 2021; 32:035707. [PMID: 33017812 DOI: 10.1088/1361-6528/abbe56] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Graphane is formed by bonding hydrogen (and deuterium) atoms to carbon atoms in the graphene mesh, with modification from the pure planar sp2 bonding towards an sp3 configuration. Atomic hydrogen (H) and deuterium (D) bonding with C atoms in fully free-standing nano porous graphene (NPG) is achieved, by exploiting low-energy proton (or deuteron) non-destructive irradiation, with unprecedented minimal introduction of defects, as determined by Raman spectroscopy and by the C 1s core level lineshape analysis. Evidence of the H- (or D-) NPG bond formation is obtained by bringing to light the emergence of a H- (or D-) related sp3-distorted component in the C 1s core level, clear fingerprint of H-C (or D-C) covalent bonding. The H (or D) bonding with the C atoms of free-standing graphene reaches more than 1/4 (or 1/3) at% coverage. This non-destructive H-NPG (or D-NPG) chemisorption is very stable at high temperatures up to about 800 K, as monitored by Raman and x-ray photoelectron spectroscopy, with complete healing and restoring of clean graphene above 920 K. The excellent chemical and temperature stability of H- (and D-) NPG opens the way not only towards the formation of semiconducting graphane on large-scale samples, but also to stable graphene functionalisation enabling futuristic applications in advanced detectors for the β-spectrum analysis.
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Affiliation(s)
| | - Elena Blundo
- Dipartimento di Fisica, Sapienza Università di Roma, P.le Aldo Moro 2, 00185 Rome, Italy
| | - Maria Grazia Betti
- Dipartimento di Fisica and INFN Sezione di Roma 1, Sapienza Università di Roma, P.le Aldo Moro 2, 00185 Rome, Italy
| | - Gianluca Cavoto
- Dipartimento di Fisica and INFN Sezione di Roma 1, Sapienza Università di Roma, P.le Aldo Moro 2, 00185 Rome, Italy
| | - Ernesto Placidi
- Dipartimento di Fisica, Sapienza Università di Roma, P.le Aldo Moro 2, 00185 Rome, Italy
| | - Antonio Polimeni
- Dipartimento di Fisica, Sapienza Università di Roma, P.le Aldo Moro 2, 00185 Rome, Italy
| | - Alessandro Ruocco
- Dipartimento di Scienze and INFN Sezione di Roma 3, Università di Roma Tre, Via della Vasca Navale, 00146 Rome, Italy
| | - Kailong Hu
- Institute of Applied Physics, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba 305-8573, Japan
| | - Yoshikazu Ito
- Institute of Applied Physics, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba 305-8573, Japan
| | - Carlo Mariani
- Dipartimento di Fisica and INFN Sezione di Roma 1, Sapienza Università di Roma, P.le Aldo Moro 2, 00185 Rome, Italy
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33
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Deuterium Adsorption on Free-Standing Graphene. NANOMATERIALS 2021; 11:nano11010130. [PMID: 33429994 PMCID: PMC7827750 DOI: 10.3390/nano11010130] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 12/31/2020] [Accepted: 01/04/2021] [Indexed: 11/21/2022]
Abstract
A suitable way to modify the electronic properties of graphene—while maintaining the exceptional properties associated with its two-dimensional (2D) nature—is its functionalisation. In particular, the incorporation of hydrogen isotopes in graphene is expected to modify its electronic properties leading to an energy gap opening, thereby rendering graphene promising for a widespread of applications. Hence, deuterium (D) adsorption on free-standing graphene was obtained by high-energy electron ionisation of D2 and ion irradiation of a nanoporous graphene (NPG) sample. This method allows one to reach nearly 50 at.% D upload in graphene, higher than that obtained by other deposition methods so far, towards low-defect and free-standing D-graphane. That evidence was deduced by X-ray photoelectron spectroscopy of the C 1s core level, showing clear evidence of the D-C sp3 bond, and Raman spectroscopy, pointing to remarkably clean and low-defect production of graphane. Moreover, ultraviolet photoelectron spectroscopy showed the opening of an energy gap in the valence band. Therefore, high-energy electron ionisation and ion irradiation is an outstanding method for obtaining low defect D-NPG with a high D upload, which is very promising for the fabrication of semiconducting graphane on large scale.
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Yildirim T, Zhang L, Neupane GP, Chen S, Zhang J, Yan H, Hasan MM, Yoshikawa G, Lu Y. Towards future physics and applications via two-dimensional material NEMS resonators. NANOSCALE 2020; 12:22366-22385. [PMID: 33150899 DOI: 10.1039/d0nr06773c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Two-dimensional materials (2Dm) offer a unique insight into the world of quantum mechanics including van der Waals (vdWs) interactions, exciton dynamics and various other nanoscale phenomena. 2Dm are a growing family consisting of graphene, hexagonal-Boron Nitride (h-BN), transition metal dichalcogenides (TMDs), monochalcogenides (MNs), black phosphorus (BP), MXenes and 2D organic crystals such as small molecules (e.g., pentacene, C8 BTBT, perylene derivatives, etc.) and polymers (e.g., COF and MOF, etc.). They exhibit unique mechanical, electrical, optical and optoelectronic properties that are highly enhanced as the surface to volume ratio increases, resulting from the transition of bulk to the few- to mono- layer limit. Such unique attributes include the manifestation of highly tuneable bandgap semiconductors, reduced dielectric screening, highly enhanced many body interactions, the ability to withstand high strains, ferromagnetism, piezoelectric and flexoelectric effects. Using 2Dm for mechanical resonators has become a promising field in nanoelectromechanical systems (NEMS) for applications involving sensors and condensed matter physics investigations. 2Dm NEMS resonators react with their environment, exhibit highly nonlinear behaviour from tension induced stiffening effects and couple different physics domains. The small size and high stiffness of these devices possess the potential of highly enhanced force sensitivities for measuring a wide variety of un-investigated physical forces. This review highlights current research in 2Dm NEMS resonators from fundamental physics and an applications standpoint, as well as presenting future possibilities using these devices.
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Affiliation(s)
- Tanju Yildirim
- Center for Functional Sensor & Actuator (CFSN), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
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Khan AR, Liu B, Lü T, Zhang L, Sharma A, Zhu Y, Ma W, Lu Y. Direct Measurement of Folding Angle and Strain Vector in Atomically Thin WS 2 Using Second-Harmonic Generation. ACS NANO 2020; 14:15806-15815. [PMID: 33179915 DOI: 10.1021/acsnano.0c06901] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Structural engineering techniques such as local strain engineering and folding provide functional control over critical optoelectronic properties of 2D materials. Local strain engineering at the nanoscale level is practically achieved via permanently deformed wrinkled nanostructures, which are reported to show photoluminescence enhancement, bandgap modulation, and funneling effect. Folding in 2D materials is reported to tune optoelecronic properties via folding angle dependent interlayer coupling and symmetry variation. The accurate and efficient monitoring of local strain vector and folding angle is important to optimize the performance of optoelectronic devices. Conventionally, the accurate measurement of both strain amplitude and strain direction in wrinkled nanostructures requires the combined usage of multiple tools resulting in manufacturing lead time and cost. Here, we demonstrate the usage of a single tool, polarization-dependent second-harmonic generation (SHG), to determine the folding angle and strain vector accurately and efficiently in ultrathin WS2. The folding angle in trilayer WS2 folds exhibiting 1-9 times SHG enhancement is probed through variable approaches such as SHG enhancement factor, maxima and minima SHG phase difference, and linear dichroism. In compressive strain induced wrinkled nanostructures, strain-dependent SHG quenching and enhancement is observed parallel and perpendicular, respectively, to the direction of the compressive strain vector, allowing us to determine the local strain vector accurately using a photoelastic approach. We further demonstrate that SHG is highly sensitive to band-nesting-induced transition (C-peak), which can be significantly modulated by strain. Our results show SHG as a powerful probe to folding angle and strain vector.
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Affiliation(s)
- Ahmed Raza Khan
- Research School of Electrical, Energy and Materials Engineering, College of Engineering and Computer Science, Australian National University, Canberra, ACT 2601, Australia
- Department of Industrial and Manufacturing Engineering, University of Engineering and Technology (Rachna College), Lahore, 54700, Pakistan
| | - Boqing Liu
- Research School of Electrical, Energy and Materials Engineering, College of Engineering and Computer Science, Australian National University, Canberra, ACT 2601, Australia
| | - Tieyu Lü
- Department of Physics and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen, 361005, China
| | - Linglong Zhang
- Research School of Electrical, Energy and Materials Engineering, College of Engineering and Computer Science, Australian National University, Canberra, ACT 2601, Australia
| | - Ankur Sharma
- Research School of Electrical, Energy and Materials Engineering, College of Engineering and Computer Science, Australian National University, Canberra, ACT 2601, Australia
| | - Yi Zhu
- Research School of Electrical, Energy and Materials Engineering, College of Engineering and Computer Science, Australian National University, Canberra, ACT 2601, Australia
| | - Wendi Ma
- Research School of Electrical, Energy and Materials Engineering, College of Engineering and Computer Science, Australian National University, Canberra, ACT 2601, Australia
| | - Yuerui Lu
- Research School of Electrical, Energy and Materials Engineering, College of Engineering and Computer Science, Australian National University, Canberra, ACT 2601, Australia
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Seo WS, Kim DK, Han JH, Park KB, Ryu SC, Min NK, Kim JH. Functionalization of Molybdenum Disulfide via Plasma Treatment and 3-Mercaptopropionic Acid for Gas Sensors. NANOMATERIALS 2020; 10:nano10091860. [PMID: 32957525 PMCID: PMC7559567 DOI: 10.3390/nano10091860] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 09/14/2020] [Accepted: 09/15/2020] [Indexed: 11/16/2022]
Abstract
Monolayer and multilayer molybdenum disulfide (MoS2) materials are semiconductors with direct/indirect bandgaps of 1.2-1.8 eV and are attractive due to their changes in response to electrical, physicochemical, biological, and mechanical factors. Since the desired electrical properties of MoS2 are known, research on its electrical properties has increased, with focus on the deposition and growth of large-area MoS2 and its functionalization. While research on the large-scale production of MoS2 is actively underway, there is a lack of studies on functionalization approaches, which are essential since functional groups can help to dissolve particles or provide adequate reactivity. Strategies for producing films of functionalized MoS2 are rare, and what methods do exist are either complex or inefficient. This work introduces an efficient way to functionalize MoS2. Functional groups are formed on the surface by exposing MoS2 with surface sulfur vacancies generated by plasma treatment to 3-mercaptopropionic acid. This technique can create 1.8 times as many carboxyl groups on the MoS2 surface compared with previously reported strategies. The MoS2-based gas sensor fabricated using the proposed method shows a 2.6 times higher sensitivity and much lower detection limit than the untreated device.
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Affiliation(s)
- Won Seok Seo
- Department of Control and Instrumentation Engineering, Korea University, 2511 Sejong-ro, Sejong-si 30019, Korea; (W.S.S.); (D.K.K.); (K.-B.P.)
| | - Dae Ki Kim
- Department of Control and Instrumentation Engineering, Korea University, 2511 Sejong-ro, Sejong-si 30019, Korea; (W.S.S.); (D.K.K.); (K.-B.P.)
| | - Ji-Hoon Han
- Department of Nanomechatronics Engineering, Pusan University, Busan, 2 Busandaehak-ro 63 beon-gil, Geumjeong-gu, Busan 46241, Korea; (J.-H.H.); (S.C.R.)
| | - Kang-Bak Park
- Department of Control and Instrumentation Engineering, Korea University, 2511 Sejong-ro, Sejong-si 30019, Korea; (W.S.S.); (D.K.K.); (K.-B.P.)
| | - Su Chak Ryu
- Department of Nanomechatronics Engineering, Pusan University, Busan, 2 Busandaehak-ro 63 beon-gil, Geumjeong-gu, Busan 46241, Korea; (J.-H.H.); (S.C.R.)
| | - Nam Ki Min
- Department of Control and Instrumentation Engineering, Korea University, 2511 Sejong-ro, Sejong-si 30019, Korea; (W.S.S.); (D.K.K.); (K.-B.P.)
- Correspondence: (N.K.M.); (J.H.K.)
| | - Joon Hyub Kim
- Department of Nanomechatronics Engineering, Pusan University, Busan, 2 Busandaehak-ro 63 beon-gil, Geumjeong-gu, Busan 46241, Korea; (J.-H.H.); (S.C.R.)
- Correspondence: (N.K.M.); (J.H.K.)
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Felton J, Blundo E, Ling S, Glover J, Kudrynskyi ZR, Makarovsky O, Kovalyuk ZD, Besley E, Walker G, Polimeni A, Patané A. The Interaction of Hydrogen with the van der Waals Crystal γ-InSe. Molecules 2020; 25:E2526. [PMID: 32481752 PMCID: PMC7321205 DOI: 10.3390/molecules25112526] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 05/22/2020] [Accepted: 05/23/2020] [Indexed: 02/03/2023] Open
Abstract
The emergence of the hydrogen economy requires development in the storage, generation and sensing of hydrogen. The indium selenide ( γ -InSe) van der Waals (vdW) crystal shows promise for technologies in all three of these areas. For these applications to be realised, the fundamental interactions of InSe with hydrogen must be understood. Here, we present a comprehensive experimental and theoretical study on the interaction of γ -InSe with hydrogen. It is shown that hydrogenation of γ -InSe by a Kaufman ion source results in a marked quenching of the room temperature photoluminescence signal and a modification of the vibrational modes of γ -InSe, which are modelled by density functional theory simulations. Our experimental and theoretical studies indicate that hydrogen is incorporated into the crystal preferentially in its atomic form. This behaviour is qualitatively different from that observed in other vdW crystals, such as transition metal dichalcogenides, where molecular hydrogen is intercalated in the vdW gaps of the crystal, leading to the formation of "bubbles" for hydrogen storage.
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Affiliation(s)
- James Felton
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK; (Z.R.K.); (O.M.)
- Advanced Materials Research Group, Faculty of Engineering, University of Nottingham, Nottingham NG7 2RD, UK; (S.L.); (G.W.)
| | - Elena Blundo
- Dipartimento di Fisica, Sapienza Università di Roma, 00185 Roma, Italy; (E.B.); (A.P.)
| | - Sanliang Ling
- Advanced Materials Research Group, Faculty of Engineering, University of Nottingham, Nottingham NG7 2RD, UK; (S.L.); (G.W.)
| | - Joseph Glover
- School of Chemistry, University of Nottingham, Nottingham NG7 2RD, UK; (J.G.); (E.B.)
| | - Zakhar R. Kudrynskyi
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK; (Z.R.K.); (O.M.)
| | - Oleg Makarovsky
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK; (Z.R.K.); (O.M.)
| | - Zakhar D. Kovalyuk
- Institute for Problems of Materials Science, National Academy of Sciences of Ukraine, Chernivtsi Branch, 58001 Chernivtsi, Ukraine;
| | - Elena Besley
- School of Chemistry, University of Nottingham, Nottingham NG7 2RD, UK; (J.G.); (E.B.)
| | - Gavin Walker
- Advanced Materials Research Group, Faculty of Engineering, University of Nottingham, Nottingham NG7 2RD, UK; (S.L.); (G.W.)
| | - Antonio Polimeni
- Dipartimento di Fisica, Sapienza Università di Roma, 00185 Roma, Italy; (E.B.); (A.P.)
| | - Amalia Patané
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK; (Z.R.K.); (O.M.)
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In-Situ Annealing and Hydrogen Irradiation of Defect-Enhanced Germanium Quantum Dot Light Sources on Silicon. CRYSTALS 2020. [DOI: 10.3390/cryst10050351] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
While light-emitting nanostructures composed of group-IV materials fulfil the mandatory compatibility with CMOS-fabrication methods, factors such as the structural stability of the nanostructures upon thermal annealing, and the ensuing photoluminescence (PL) emission properties, are of key relevance. In addition, the possibility of improving the PL efficiency by suitable post-growth treatments, such as hydrogen irradiation, is important too. We address these issues for self-assembled Ge quantum dots (QDs) that are co-implanted with Ge ions during their epitaxial growth. The presence of defects introduced by the impinging Ge ions results in pronounced PL-emission at telecom wavelengths up to room temperature (RT) and above. This approach allows us to overcome the severe limitations of light generation in the indirect-band-gap group-IV materials. By performing in-situ annealing, we demonstrate a high PL-stability of the defect-enhanced QD (DEQD) system against thermal treatment up to 600 °C for at least 2 h, even though the Ge QDs are structurally affected by Si/Ge intermixing via bulk diffusion. The latter, in turn, allows for emission tuning of the DEQDs over the entire telecom wavelength range from 1.3 µm to 1.55 µm. Two quenching mechanisms for light-emission are discussed; first, luminescence quenching at high PL recording temperatures, associated with the thermal escape of holes to the surrounding wetting layer; and second, annealing-induced PL-quenching at annealing temperatures >650 °C, which is associated with a migration of the defect complex out of the QD. We show that low-energy ex-situ proton irradiation into the Si matrix further improves the light emission properties of the DEQDs, whereas proton irradiation-related optically active G-centers do not affect the room temperature luminescence properties of DEQDs.
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