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Rodríguez Á, Çakıroğlu O, Li H, Carrascoso F, Mompean F, Garcia-Hernandez M, Munuera C, Castellanos-Gomez A. Improved Strain Transfer Efficiency in Large-Area Two-Dimensional MoS 2 Obtained by Gold-Assisted Exfoliation. J Phys Chem Lett 2024; 15:6355-6362. [PMID: 38857301 PMCID: PMC11194808 DOI: 10.1021/acs.jpclett.4c00855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 05/31/2024] [Accepted: 06/05/2024] [Indexed: 06/12/2024]
Abstract
Strain engineering represents a pivotal approach to tailoring the optoelectronic properties of two-dimensional (2D) materials. However, typical bending experiments often encounter challenges, such as layer slippage and inefficient transfer of strain from the substrate to the 2D material, hindering the realization of their full potential. In our study, using molybdenum disulfide (MoS2) as a model 2D material, we have demonstrated that layers obtained through gold-assisted exfoliation on flexible polycarbonate substrates can achieve high-efficient strain transfer while also mitigating slippage effects, owing to the strong interfacial interaction established between MoS2 and gold. We employ differential reflectance and Raman spectroscopy for monitoring strain changes. We successfully applied uniaxial strains of up to 3% to trilayer MoS2, resulting in a notable energy shift of 168 meV. These values are comparable only to those obtained in encapsulated samples with organic polymers.
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Affiliation(s)
- Álvaro Rodríguez
- Materials Science Factory, Instituto de Ciencia de Materiales de Madrid (ICMM)−Consejo
Superior de Investigaciones Científicas (CSIC), C. Sor Juana Inés de la Cruz,
3, 28049 Madrid, Spain
| | - Onur Çakıroğlu
- Materials Science Factory, Instituto de Ciencia de Materiales de Madrid (ICMM)−Consejo
Superior de Investigaciones Científicas (CSIC), C. Sor Juana Inés de la Cruz,
3, 28049 Madrid, Spain
| | - Hao Li
- Materials Science Factory, Instituto de Ciencia de Materiales de Madrid (ICMM)−Consejo
Superior de Investigaciones Científicas (CSIC), C. Sor Juana Inés de la Cruz,
3, 28049 Madrid, Spain
| | - Felix Carrascoso
- Materials Science Factory, Instituto de Ciencia de Materiales de Madrid (ICMM)−Consejo
Superior de Investigaciones Científicas (CSIC), C. Sor Juana Inés de la Cruz,
3, 28049 Madrid, Spain
| | - Federico Mompean
- Materials Science Factory, Instituto de Ciencia de Materiales de Madrid (ICMM)−Consejo
Superior de Investigaciones Científicas (CSIC), C. Sor Juana Inés de la Cruz,
3, 28049 Madrid, Spain
| | - Mar Garcia-Hernandez
- Materials Science Factory, Instituto de Ciencia de Materiales de Madrid (ICMM)−Consejo
Superior de Investigaciones Científicas (CSIC), C. Sor Juana Inés de la Cruz,
3, 28049 Madrid, Spain
| | - Carmen Munuera
- Materials Science Factory, Instituto de Ciencia de Materiales de Madrid (ICMM)−Consejo
Superior de Investigaciones Científicas (CSIC), C. Sor Juana Inés de la Cruz,
3, 28049 Madrid, Spain
| | - Andres Castellanos-Gomez
- Materials Science Factory, Instituto de Ciencia de Materiales de Madrid (ICMM)−Consejo
Superior de Investigaciones Científicas (CSIC), C. Sor Juana Inés de la Cruz,
3, 28049 Madrid, Spain
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2
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Steeger P, Graalmann JH, Schmidt R, Kupenko I, Sanchez-Valle C, Marauhn P, Deilmann T, de Vasconcellos SM, Rohlfing M, Bratschitsch R. Pressure Dependence of Intra- and Interlayer Excitons in 2H-MoS 2 Bilayers. NANO LETTERS 2023; 23:8947-8952. [PMID: 37734032 DOI: 10.1021/acs.nanolett.3c02428] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/23/2023]
Abstract
The optical and electronic properties of multilayer transition metal dichalcogenides differ significantly from their monolayer counterparts due to interlayer interactions. The separation of individual layers can be tuned in a controlled way by applying pressure. Here, we use a diamond anvil cell to compress bilayers of 2H-MoS2 in the gigapascal range. By measuring optical transmission spectra, we find that increasing pressure leads to a decrease in the energy splitting between the A and the interlayer exciton. Comparing our experimental findings with ab initio calculations, we conclude that the observed changes are not due to the commonly assumed hydrostatic compression. This effect is attributed to the MoS2 bilayer adhering to the diamond, which reduces the in-plane compression. Moreover, we demonstrate that the distinct real-space distributions and resulting contributions from the valence band account for the different pressure dependencies of the inter- and intralayer excitons in compressed MoS2 bilayers.
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Affiliation(s)
- Paul Steeger
- Institute of Physics and Center for Nanotechnology, University of Münster, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany
| | - Jan-Hauke Graalmann
- Institute of Solid State Theory, University of Münster, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany
| | - Robert Schmidt
- Institute of Physics and Center for Nanotechnology, University of Münster, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany
| | - Ilya Kupenko
- Institute of Mineralogy, University of Münster, Corrensstr. 24, 48149 Münster, Germany
| | - Carmen Sanchez-Valle
- Institute of Mineralogy, University of Münster, Corrensstr. 24, 48149 Münster, Germany
| | - Philipp Marauhn
- Institute of Solid State Theory, University of Münster, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany
| | - Thorsten Deilmann
- Institute of Solid State Theory, University of Münster, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany
| | | | - Michael Rohlfing
- Institute of Solid State Theory, University of Münster, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany
| | - Rudolf Bratschitsch
- Institute of Physics and Center for Nanotechnology, University of Münster, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany
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3
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Sun H, Wang L, Li Z, Yan X, Zhang X, Guo J, Liu P. Strain engineering on electronic structure, effective mass and charge carrier mobility in monolayer YBr 3. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 36:015501. [PMID: 37714188 DOI: 10.1088/1361-648x/acfa56] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 09/15/2023] [Indexed: 09/17/2023]
Abstract
In recent years, two-dimensional materials have significant prospects for applications in nanoelectronic devices due to their unique physical properties. In this paper, the strain effect on the electronic structure, effective mass, and charge carrier mobility of monolayer yttrium bromide (YBr3) is systematically investigated using first-principles calculation based on density functional theory. It is found that the monolayer YBr3undergoes energy band gap reduction under the increasing compressive strain. The effective mass and charge carrier mobility can be effectively tuned by the applied compressive strain. Under the uniaxial compressive strain along the zigzag direction, the hole effective mass in the zigzag direction (mao1_h) can decrease from 1.64m0to 0.45m0. In addition, when the uniaxial compressive strain is applied, the electron and hole mobility can up to ∼103cm2V-1s-1. The present investigations emphasize that monolayer YBr3is expected to be a candidate material for the preparation of new high-performance nanoelectronic devices by strain engineering.
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Affiliation(s)
- Huaizheng Sun
- Key Laboratory of Brain-Like Neuromorphic Devices and Systems of Hebei Province, College of Electronic and Information Engineering, Hebei University, Baoding 071002, People's Republic of China
| | - Linxia Wang
- Key Laboratory of Brain-Like Neuromorphic Devices and Systems of Hebei Province, College of Electronic and Information Engineering, Hebei University, Baoding 071002, People's Republic of China
| | - Zhixiang Li
- Key Laboratory of Brain-Like Neuromorphic Devices and Systems of Hebei Province, College of Electronic and Information Engineering, Hebei University, Baoding 071002, People's Republic of China
| | - Xiaobing Yan
- Key Laboratory of Brain-Like Neuromorphic Devices and Systems of Hebei Province, College of Electronic and Information Engineering, Hebei University, Baoding 071002, People's Republic of China
| | - Xin Zhang
- Key Laboratory of Brain-Like Neuromorphic Devices and Systems of Hebei Province, College of Electronic and Information Engineering, Hebei University, Baoding 071002, People's Republic of China
| | - Jianxin Guo
- Hebei Key Lab of Optic-Electronic Information and Materials, College of Physics Science and Technology, Hebei University, Baoding 071002, People's Republic of China
| | - Pan Liu
- Key Laboratory of Brain-Like Neuromorphic Devices and Systems of Hebei Province, College of Electronic and Information Engineering, Hebei University, Baoding 071002, People's Republic of China
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4
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Wang K, Ren K, Hou Y, Cheng Y, Zhang G. Magnon-phonon coupling: from fundamental physics to applications. Phys Chem Chem Phys 2023; 25:21802-21815. [PMID: 37581291 DOI: 10.1039/d3cp02683c] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/16/2023]
Abstract
In recent decades, there are immense applications for bulk and few-layer magnetic insulators in biomedicine, data storage, and signal transfer. In these applications, the interaction between spin and lattice vibration has significant impacts on the device performance. In this article, we systematically review the fundamental physical aspects of magnon-phonon coupling in magnetic insulators. We first introduce the fundamental physics of magnons and magnon-phonon coupling in magnetic insulators and then discuss the influence of magnon-phonon coupling on the properties of magnons and phonons. Finally, a summary is presented, and we also discuss the possible open problems in this field. This article presents the advanced understanding of magnon-phonon coupling in magnetic insulators, which provides new opportunities for improving various possible applications.
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Affiliation(s)
- Ke Wang
- School of Automation, Xi'an University of Posts and Telecommunications, Shaanxi, 710121, China
- Monash Suzhou Research Institute, Monash University, Suzhou Industrial Park, Suzhou 215000, PR China.
| | - Kai Ren
- School of Mechanical and Electronic Engineering, Nanjing Forestry University, Nanjing, Jiangsu 210042, China
| | - Yinlong Hou
- School of Automation, Xi'an University of Posts and Telecommunications, Shaanxi, 710121, China
| | - Yuan Cheng
- Monash Suzhou Research Institute, Monash University, Suzhou Industrial Park, Suzhou 215000, PR China.
- Department of Materials Science and Engineering, Monash University, VIC 3800, Australia
| | - Gang Zhang
- Institute of High Performance Computing, A*STAR, 138632, Singapore.
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5
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Hsieh YC, Lin ZY, Fung SJ, Lu WS, Ho SC, Hong SP, Ho SZ, Huang CH, Watanabe K, Taniguchi T, Chan YH, Chen YC, Wu CL, Chen TM. Engineering the Strain and Interlayer Excitons of 2D Materials via Lithographically Engraved Hexagonal Boron Nitride. NANO LETTERS 2023; 23:7244-7251. [PMID: 37348137 DOI: 10.1021/acs.nanolett.3c01208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/24/2023]
Abstract
Strain engineering has quickly emerged as a viable option to modify the electronic, optical, and magnetic properties of 2D materials. However, it remains challenging to arbitrarily control the strain. Here we show that, by creating atomically flat surface nanostructures in hexagonal boron nitride, we achieve an arbitrary on-chip control of both the strain distribution and magnitude on high-quality molybdenum disulfide. The phonon and exciton emissions are shown to vary in accordance with our strain field designs, enabling us to write and draw any photoluminescence color image in a single chip. Moreover, our strain engineering offers a powerful means to significantly and controllably alter the strengths and energies of interlayer excitons at room temperature. This method can be easily extended to other material systems and offers promise for functional excitonic devices.
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Affiliation(s)
- Yu-Chiang Hsieh
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Zhen-You Lin
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Shin-Ji Fung
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Wen-Shin Lu
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
| | - Sheng-Chin Ho
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Siang-Ping Hong
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Sheng-Zhu Ho
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Chiu-Hua Huang
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Namiki 1-1, Tsukuba, 305-0044, Ibaraki, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Namiki 1-1, Tsukuba, 305-0044, Ibaraki, Japan
| | - Yang-Hao Chan
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan
- Physics Division, National Center for Theoretical Sciences, Taipei 106, Taiwan
| | - Yi-Chun Chen
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
- Center for Quantum Frontiers of Research & Technology (QFort), National Cheng Kung University, Tainan 701, Taiwan
| | - Chung-Lin Wu
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
- Center for Quantum Frontiers of Research & Technology (QFort), National Cheng Kung University, Tainan 701, Taiwan
| | - Tse-Ming Chen
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
- Center for Quantum Frontiers of Research & Technology (QFort), National Cheng Kung University, Tainan 701, Taiwan
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6
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Yu Y, Dong CD, Binder R, Schumacher S, Ning CZ. Strain-Induced Indirect-to-Direct Bandgap Transition, Photoluminescence Enhancement, and Linewidth Reduction in Bilayer MoTe 2. ACS NANO 2023; 17:4230-4238. [PMID: 36812007 DOI: 10.1021/acsnano.2c01665] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Two-dimensional (2D) layered materials provide an ideal platform for engineering electronic and optical properties through strain control because of their extremely high mechanical elasticity and sensitive dependence of material properties on mechanical strain. In this paper, a combined experimental and theoretical effort is made to investigate the effects of mechanical strain on various spectral features of bilayer MoTe2 photoluminescence (PL). We found that bilayer MoTe2 can be converted from an indirect to a direct bandgap material through strain engineering, resulting in a photoluminescence enhancement by a factor of 2.24. Over 90% of the PL comes from photons emitted by the direct excitons at the maximum strain applied. Importantly, we show that strain effects lead to a reduction of the overall linewidth of PL by as much as 36.6%. We attribute the dramatic decrease of linewidth to a strain-induced complex interplay among various excitonic varieties such as direct bright excitons, trions, and indirect excitons. Our experimental results on direct and indirect exciton emission features are explained by theoretical exciton energies that are based on first-principles electronic band structure calculations. The consistent theory-experimental trend shows that the enhancement of PL and the reduction of linewidth are the consequences of the increasing direct exciton contribution with the increase of strain. Our results demonstrate that strain engineering can lead to a PL quality of the bilayer MoTe2 comparable to that of the monolayer counterpart. The additional benefit of a longer emission wavelength makes the bilayer MoTe2 more suitable for silicon-photonics integration due to the reduced silicon absorption.
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Affiliation(s)
- Yueyang Yu
- School of Electrical, Energy, and Computer Engineering, Arizona State University, Tempe, Arizona 85287, United States
| | - Chuan-Ding Dong
- Department of Physics and Center for Optoelectronics and Photonics Paderborn (CeOPP), Paderborn University, Paderborn 33098, Germany
| | - Rolf Binder
- Wyant College of Optical Sciences, University of Arizona, Tucson, Arizona 85721, United States
| | - Stefan Schumacher
- Department of Physics and Center for Optoelectronics and Photonics Paderborn (CeOPP), Paderborn University, Paderborn 33098, Germany
- Wyant College of Optical Sciences, University of Arizona, Tucson, Arizona 85721, United States
| | - Cun-Zheng Ning
- School of Electrical, Energy, and Computer Engineering, Arizona State University, Tempe, Arizona 85287, United States
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7
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Raiber S, Faria Junior PE, Falter D, Feldl S, Marzena P, Watanabe K, Taniguchi T, Fabian J, Schüller C. Ultrafast pseudospin quantum beats in multilayer WSe 2 and MoSe 2. Nat Commun 2022; 13:4997. [PMID: 36008400 PMCID: PMC9411176 DOI: 10.1038/s41467-022-32534-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 08/04/2022] [Indexed: 11/09/2022] Open
Abstract
Layered van-der-Waals materials with hexagonal symmetry offer an extra degree of freedom to their electrons, the so-called valley index or valley pseudospin, which behaves conceptually like the electron spin. Here, we present investigations of excitonic transitions in mono- and multilayer WSe2 and MoSe2 materials by time-resolved Faraday ellipticity (TRFE) with in-plane magnetic fields, B∥, of up to 9 T. In monolayer samples, the measured TRFE time traces are almost independent of B∥, which confirms a close to zero in-plane exciton g factor g∥, consistent with first-principles calculations. In contrast, we observe pronounced temporal oscillations in multilayer samples for B∥ > 0. Our first-principles calculations confirm the presence of a non-zero g∥ for the multilayer samples. We propose that the oscillatory TRFE signal in the multilayer samples is caused by pseudospin quantum beats of excitons, which is a manifestation of spin- and pseudospin layer locking in the multilayer samples.
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Affiliation(s)
- Simon Raiber
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg, D-93040, Regensburg, Germany
| | - Paulo E Faria Junior
- Institut für Theoretische Physik, Universität Regensburg, D-93040, Regensburg, Germany
| | - Dennis Falter
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg, D-93040, Regensburg, Germany
| | - Simon Feldl
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg, D-93040, Regensburg, Germany
| | - Petter Marzena
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg, D-93040, Regensburg, Germany
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Ibaraki, 305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Ibaraki, 305-0044, Japan
| | - Jaroslav Fabian
- Institut für Theoretische Physik, Universität Regensburg, D-93040, Regensburg, Germany
| | - Christian Schüller
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg, D-93040, Regensburg, Germany.
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8
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Li Z, Chen Y, Liu S, Li W, Liu L, Song W, Lu D, Ma L, Yang X, Xie Z, Duan X, Yang Z, Wang Y, Liao L, Liu Y. Strain Releasing of Flexible 2D Electronics through van der Waals Sliding Contact. ACS NANO 2022; 16:13152-13159. [PMID: 35969178 DOI: 10.1021/acsnano.2c06214] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Two-dimensional (2D) materials have demonstrated promising potential for flexible electronics, owning to their atomic thin body thickness and dangling-bond-free surface. Here, we report a sliding contact device structure for efficient strain releasing. By fabricating a weakly coupled metal-2D junction with a van der Waals (vdW) gap in between, the applied strain could be effectively released through their interface sliding; hence minimized strain is transferred to the 2D lattice. Therefore, we observed stable device behavior with electrodes stretching over 110%, much higher than 2D devices using evaporated metal contacts. Furthermore, through multicycle straining-releasing measurements, we found the electrodes still form intimate contact with nearly constant contact resistance during sliding, confirming the optimization of device flexibility and electrical properties at the same time. Finally, we demonstrate this vdW sliding contact is a general device geometry and could be well-extended to various 2D or 3D bulk materials, leading to devices with much higher strain tolerance.
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Affiliation(s)
- Zhiwei Li
- Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Yang Chen
- Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Songlong Liu
- Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Wanying Li
- Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Liting Liu
- Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Wenjing Song
- Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Donglin Lu
- Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Likuan Ma
- Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Xiangdong Yang
- State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Zhengdao Xie
- Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Xidong Duan
- State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Zeyu Yang
- Chengdu ROTEX Technology, Chengdu 610043, China
| | - Yiliu Wang
- Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Lei Liao
- Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Yuan Liu
- Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China
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9
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Temperature induced modulation of resonant Raman scattering in bilayer 2H-MoS2. Sci Rep 2022; 12:14169. [PMID: 35986062 PMCID: PMC9391345 DOI: 10.1038/s41598-022-18439-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 08/11/2022] [Indexed: 11/15/2022] Open
Abstract
The temperature evolution of the resonant Raman scattering from high-quality bilayer 2H-MoS\documentclass[12pt]{minimal}
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\begin{document}$$_{2}$$\end{document}2 encapsulated in hexagonal BN flakes is presented. The observed resonant Raman scattering spectrum as initiated by the laser energy of 1.96 eV, close to the A excitonic resonance, shows rich and distinct vibrational features that are otherwise not observed in non-resonant scattering. The appearance of 1st and 2nd order phonon modes is unambiguously observed in a broad range of temperatures from 5 to 320 K. The spectrum includes the Raman-active modes, i.e. E\documentclass[12pt]{minimal}
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\begin{document}$$\Gamma$$\end{document}Γ). The temperature evolution of the Raman scattering spectrum brings forward key observations, as the integrated intensity profiles of different phonon modes show diverse trends. The Raman-active A\documentclass[12pt]{minimal}
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\begin{document}$$\Gamma$$\end{document}Γ) mode, which dominates the Raman scattering spectrum at T = 5 K quenches with increasing temperature. Surprisingly, at room temperature the B\documentclass[12pt]{minimal}
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10
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Abstract
Controlling the interlayer coupling by tuning lattice parameters through pressure engineering is an important route for tailoring the optoelectronic properties of two-dimensional materials. In this work, we report a pressure-dependent study on the exciton transitions of bilayer MoS2 exfoliated on a diamond anvil surface. The applied hydrostatic pressure changes from ambient pressure up to 11.05 GPa using a diamond anvil cell device. Raman, photoluminescence, and reflectivity spectra at room temperature are analyzed to characterize the interlayer coupling of this bilayer system. With the increase of pressure, the indirect exciton emission disappears completely at about 5 GPa. Importantly, we clearly observed the interlayer exciton from the reflectivity spectra, which becomes invisible at a low pressure around 1.26 GPa. This indicates that the interlayer exciton is very sensitive to the hydrostatic pressure due to the oscillator strength transfer from the direct transition to the indirect one.
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11
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Deng JP, Li HJ, Ma XF, Liu XY, Cui Y, Ma XJ, Li ZQ, Wang ZW. Self-Trapped Interlayer Excitons in van der Waals Heterostructures. J Phys Chem Lett 2022; 13:3732-3739. [PMID: 35445599 DOI: 10.1021/acs.jpclett.2c00565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The self-trapped state (STS) of the interlayer exciton (IX) has aroused enormous interest owing to its significant impact on the fundamental properties of the van der Waals heterostructures (vdWHs). Nevertheless, the microscopic mechanisms of STS are still controversial. Herein, we study the corrections of the binding energies of the IXs stemming from the exciton-interface optical phonon coupling in four kinds of vdWHs and find that these IXs are in the STS for the appropriate ratio of the electron and hole effective masses. We show that these self-trapped IXs could be classified into type I with the increasing binding energy in the tens of millielectronvolts range, which are very agreement with the red-shift of the IX spectra in experiments, and type II with the decreasing binding energy, which provides a possible explanation for the blue-shift and broad line width of the IX's spectra at low temperatures. Moreover, these two types of exciton states could be transformed into each other by adjusting the structural parameters of vdWHs. These results not only provide an in-depth understanding for the self-trapped mechanism but also shed light on the modulations of IXs in vdWHs.
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Affiliation(s)
- Jia-Pei Deng
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Department of Physics, School of Science, Tianjin University, Tianjin 300354, Tianjin, China
| | - Hong-Juan Li
- College of Physics and Intelligent Manufacturing Engineering, Chifeng University, Chifeng 024000, Inner Mongolia, China
| | - Xu-Fei Ma
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Department of Physics, School of Science, Tianjin University, Tianjin 300354, Tianjin, China
| | - Xiao-Yi Liu
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Department of Physics, School of Science, Tianjin University, Tianjin 300354, Tianjin, China
| | - Yu Cui
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Department of Physics, School of Science, Tianjin University, Tianjin 300354, Tianjin, China
| | - Xin-Jun Ma
- Research Team of Extreme Condition Physics, College of Mathematics and Physics, Inner Mongolia Minzu University, Tongliao 028043, Inner Mongolia, China
| | - Zhi-Qing Li
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Department of Physics, School of Science, Tianjin University, Tianjin 300354, Tianjin, China
| | - Zi-Wu Wang
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Department of Physics, School of Science, Tianjin University, Tianjin 300354, Tianjin, China
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12
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Bignardi L, Mahatha SK, Lizzit D, Bana H, Travaglia E, Lacovig P, Sanders C, Baraldi A, Hofmann P, Lizzit S. Anisotropic strain in epitaxial single-layer molybdenum disulfide on Ag(110). NANOSCALE 2021; 13:18789-18798. [PMID: 34751294 DOI: 10.1039/d1nr05584d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
In this work we prove that ordered single-layer MoS2 can be grown epitaxially on Ag(110), despite the different crystalline geometry of adsorbate and substrate. A comprehensive investigation of electronic and structural features of this interface is carried out by combining several techniques. Photoelectron diffraction experiments show that only two mirror crystalline domains coexist in equal amount in the grown layer. Angle-resolved valence band photoelectron spectroscopy shows that MoS2 undergoes a semiconductor-to-metal transition. Low-energy electron diffraction and scanning-tunneling microscopy experiments reveal the formation of a commensurate moiré superlattice at the interface, which implies an anisotropic uniaxial strain of the MoS2 crystalline lattice of ca. 3% in the [11̄0] direction of the Ag(110) surface. These outcomes suggest that the epitaxial growth on anisotropic substrates might be an effective and scalable method to generate a controlled and homogeneous strain in MoS2 and possibly other transition-metal dichalcogenides.
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Affiliation(s)
- Luca Bignardi
- Department of Physics, University of Trieste, via Valerio 2, 34127 Trieste, Italy.
- Elettra Sincrotrone Trieste, Strada Statale 14 km. 163.5 in AREA Science Park, 34149 Trieste, Italy.
| | - Sanjoy K Mahatha
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Denmark.
| | - Daniel Lizzit
- Elettra Sincrotrone Trieste, Strada Statale 14 km. 163.5 in AREA Science Park, 34149 Trieste, Italy.
| | - Harsh Bana
- Department of Physics, University of Trieste, via Valerio 2, 34127 Trieste, Italy.
| | - Elisabetta Travaglia
- Department of Physics, University of Trieste, via Valerio 2, 34127 Trieste, Italy.
| | - Paolo Lacovig
- Elettra Sincrotrone Trieste, Strada Statale 14 km. 163.5 in AREA Science Park, 34149 Trieste, Italy.
| | - Charlotte Sanders
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Denmark.
| | - Alessandro Baraldi
- Department of Physics, University of Trieste, via Valerio 2, 34127 Trieste, Italy.
- Elettra Sincrotrone Trieste, Strada Statale 14 km. 163.5 in AREA Science Park, 34149 Trieste, Italy.
- IOM-CNR, Laboratorio TASC, AREA Science Park, Strada Statale 14, km. 163.5, 34149 Trieste, Italy
| | - Philip Hofmann
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Denmark.
| | - Silvano Lizzit
- Elettra Sincrotrone Trieste, Strada Statale 14 km. 163.5 in AREA Science Park, 34149 Trieste, Italy.
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13
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Sharona H, Bhat U. Nature of optical excitations and bandgap of Re xMo 1-xS 2alloy at nanoscale probed from high resolution low loss electron energy loss spectroscopy. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:455901. [PMID: 34380118 DOI: 10.1088/1361-648x/ac1caf] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 08/11/2021] [Indexed: 06/13/2023]
Abstract
The two-dimensional (2D) transitional metal dichalcogenides (TMDS) have become an intensive research topic recently. The alloys of these TMDs have offered continuous tunability of the bandstructure and carrier concentration, providing a new opportunity for various device applications. Here the rich variations in optical excitations in RexMo1-xS2alloy at the nanoscale region are shown. The alloy bandgap and charge response are probed by low-loss high-resolution transmission electron energy loss spectroscopy (HR-EELS). Concurrent density functional theory calculations revealed many electronic structures from n-type semiconductors to metallic and p-type semiconducting nature with band bowing effect. The alloying-induced Peierls distortion leads to a change in crystal symmetry and decreased interlayer coupling. These alloys undergo indirect to direct bandgap transition with the function of Re concentration. These unique correlated structural and electronic properties of these 2D alloys can be potentially applicable for various electronic and optoelectronic devices.
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Affiliation(s)
- H Sharona
- International Centre for Materials Science, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - U Bhat
- International Centre for Materials Science, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
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14
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Peimyoo N, Deilmann T, Withers F, Escolar J, Nutting D, Taniguchi T, Watanabe K, Taghizadeh A, Craciun MF, Thygesen KS, Russo S. Electrical tuning of optically active interlayer excitons in bilayer MoS 2. NATURE NANOTECHNOLOGY 2021; 16:888-893. [PMID: 34083771 DOI: 10.1038/s41565-021-00916-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 04/19/2021] [Indexed: 06/12/2023]
Abstract
Interlayer (IL) excitons, comprising electrons and holes residing in different layers of van der Waals bonded two-dimensional semiconductors, have opened new opportunities for room-temperature excitonic devices. So far, two-dimensional IL excitons have been realized in heterobilayers with type-II band alignment. However, the small oscillator strength of the resulting IL excitons and difficulties with producing heterostructures with definite crystal orientation over large areas have challenged the practical applicability of this design. Here, following the theoretical prediction and recent experimental confirmation of the existence of IL excitons in bilayer MoS2, we demonstrate the electrical control of such excitons up to room temperature. We find that the IL excitonic states preserve their large oscillator strength as their energies are manipulated by the electric field. We attribute this effect to the mixing of the pure IL excitons with intralayer excitons localized in a single layer. By applying an electric field perpendicular to the bilayer MoS2 crystal plane, excitons with IL character split into two peaks with an X-shaped field dependence as a clear fingerprint of the shift of the monolayer bands with respect to each other. Finally, we demonstrate the full control of the energies of IL excitons distributed homogeneously over a large area of our device.
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Affiliation(s)
- Namphung Peimyoo
- Centre for Graphene Science, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UK
| | - Thorsten Deilmann
- Institut für Festkörpertheorie, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Freddie Withers
- Centre for Graphene Science, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UK
| | - Janire Escolar
- Centre for Graphene Science, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UK
| | - Darren Nutting
- Centre for Graphene Science, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UK
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
| | - Kenji Watanabe
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
| | - Alireza Taghizadeh
- Department of Materials and Production, Aalborg University, Aalborg, Denmark
- CAMD, Department of Physics, Technical University of Denmark, Kongens Lyngby, Denmark
- Center for Nanostructured Graphene (CNG), Department of Physics, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Monica Felicia Craciun
- Centre for Graphene Science, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UK
| | - Kristian Sommer Thygesen
- CAMD, Department of Physics, Technical University of Denmark, Kongens Lyngby, Denmark
- Center for Nanostructured Graphene (CNG), Department of Physics, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Saverio Russo
- Centre for Graphene Science, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UK.
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15
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Cho C, Wong J, Taqieddin A, Biswas S, Aluru NR, Nam S, Atwater HA. Highly Strain-Tunable Interlayer Excitons in MoS 2/WSe 2 Heterobilayers. NANO LETTERS 2021; 21:3956-3964. [PMID: 33914542 DOI: 10.1021/acs.nanolett.1c00724] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Interlayer excitons in heterobilayers of transition-metal dichalcogenides (TMDCs) have generated enormous interest due to their permanent vertical dipole moments and long lifetimes. However, the effects of mechanical strain on the optoelectronic properties of interlayer excitons in heterobilayers remain relatively uncharacterized. Here, we experimentally demonstrate strain tuning of Γ-K interlayer excitons in molybdenum disulfide and tungsten diselenide (MoS2/WSe2) wrinkled heterobilayers and obtain a deformation potential constant of ∼107 meV/% uniaxial strain, which is approximately twice that of the intralayer excitons in the constituent monolayers. We further observe a nonmonotonic dependence of the interlayer exciton photoluminescence intensity with strain, which we interpret as being due to the sensitivity of the Γ point to band hybridization arising from the competition between in-plane strain and out-of-plane interlayer coupling. Strain engineering with interlayer excitons in TMDC heterobilayers offers higher strain tunability and new degrees of freedom compared to their monolayer counterparts.
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Affiliation(s)
- Chullhee Cho
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Joeson Wong
- Department of Applied Physics and Materials Science, California Institute of Technology, Pasadena, California 91125, United States
| | - Amir Taqieddin
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Souvik Biswas
- Department of Applied Physics and Materials Science, California Institute of Technology, Pasadena, California 91125, United States
| | - Narayana R Aluru
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - SungWoo Nam
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Harry A Atwater
- Department of Applied Physics and Materials Science, California Institute of Technology, Pasadena, California 91125, United States
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17
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Lorchat E, Selig M, Katsch F, Yumigeta K, Tongay S, Knorr A, Schneider C, Höfling S. Excitons in Bilayer MoS_{2} Displaying a Colossal Electric Field Splitting and Tunable Magnetic Response. PHYSICAL REVIEW LETTERS 2021; 126:037401. [PMID: 33543981 DOI: 10.1103/physrevlett.126.037401] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 09/29/2020] [Accepted: 12/16/2020] [Indexed: 06/12/2023]
Abstract
van der Waals heterostructures composed of transition metal dichalcogenide monolayers (TMDCs) are characterized by their truly rich excitonic properties which are determined by their structural, geometric, and electronic properties: In contrast to pure monolayers, electrons and holes can be hosted in different materials, resulting in highly tunable dipolar many-particle complexes. However, for genuine spatially indirect excitons, the dipolar nature is usually accompanied by a notable quenching of the exciton oscillator strength. Via electric and magnetic field dependent measurements, we demonstrate that a slightly biased pristine bilayer MoS_{2} hosts strongly dipolar excitons, which preserve a strong oscillator strength. We scrutinize their giant dipole moment, and shed further light on their orbital and valley physics via bias-dependent magnetic field measurements.
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Affiliation(s)
- Etienne Lorchat
- Technische Physik, Wilhelm-Conrad-Röntgen-Research Center for Complex Material Systems, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Malte Selig
- Institut für Theoretische Physik Nichtlineare Optik und Quantenelektronik, Technische Universität Berlin, D-10623 Berlin, Germany
| | - Florian Katsch
- Institut für Theoretische Physik Nichtlineare Optik und Quantenelektronik, Technische Universität Berlin, D-10623 Berlin, Germany
| | - Kentaro Yumigeta
- School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, Arizona 85287, USA
| | - Sefaattin Tongay
- School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, Arizona 85287, USA
| | - Andreas Knorr
- Institut für Theoretische Physik Nichtlineare Optik und Quantenelektronik, Technische Universität Berlin, D-10623 Berlin, Germany
| | - Christian Schneider
- Technische Physik, Wilhelm-Conrad-Röntgen-Research Center for Complex Material Systems, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
- Institute of Physics, University of Oldenburg, 26129 Oldenburg, Germany
| | - Sven Höfling
- Technische Physik, Wilhelm-Conrad-Röntgen-Research Center for Complex Material Systems, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
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Leisgang N, Shree S, Paradisanos I, Sponfeldner L, Robert C, Lagarde D, Balocchi A, Watanabe K, Taniguchi T, Marie X, Warburton RJ, Gerber IC, Urbaszek B. Giant Stark splitting of an exciton in bilayer MoS 2. NATURE NANOTECHNOLOGY 2020; 15:901-907. [PMID: 32778806 DOI: 10.1038/s41565-020-0750-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 07/06/2020] [Indexed: 06/11/2023]
Abstract
Transition metal dichalcogenides (TMDs) constitute a versatile platform for atomically thin optoelectronics devices and spin-valley memory applications. In monolayer TMDs the optical absorption is strong, but the transition energy cannot be tuned as the neutral exciton has essentially no out-of-plane static electric dipole1,2. In contrast, interlayer exciton transitions in heterobilayers are widely tunable in applied electric fields, but their coupling to light is substantially reduced. In this work, we show tuning over 120 meV of interlayer excitons with a high oscillator strength in bilayer MoS2 due to the quantum-confined Stark effect3. We optically probed the interaction between intra- and interlayer excitons as they were energetically tuned into resonance. Interlayer excitons interact strongly with intralayer B excitons, as demonstrated by a clear avoided crossing, whereas the interaction with intralayer A excitons is substantially weaker. Our observations are supported by density functional theory (DFT) calculations, which include excitonic effects. In MoS2 trilayers, our experiments uncovered two types of interlayer excitons with and without in-built electric dipoles. Highly tunable excitonic transitions with large in-built dipoles and oscillator strengths will result in strong exciton-exciton interactions and therefore hold great promise for non-linear optics with polaritons.
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Affiliation(s)
- Nadine Leisgang
- Department of Physics, University of Basel, Basel, Switzerland
| | - Shivangi Shree
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, Toulouse, France
| | | | | | - Cedric Robert
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, Toulouse, France
| | | | - Andrea Balocchi
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, Toulouse, France
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Ibaraki, Japan
| | - Takashi Taniguchi
- International Center for Materials Anorthite, National Institute for Materials Science, Ibaraki, Japan
| | - Xavier Marie
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, Toulouse, France
| | | | - Iann C Gerber
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, Toulouse, France
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Niehues I, Marauhn P, Deilmann T, Wigger D, Schmidt R, Arora A, Michaelis de Vasconcellos S, Rohlfing M, Bratschitsch R. Strain tuning of the Stokes shift in atomically thin semiconductors. NANOSCALE 2020; 12:20786-20796. [PMID: 33034315 DOI: 10.1039/d0nr04557h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Atomically thin layers of transition metal dichalcogenides (TMDC) have exceptional optical properties, exhibiting a characteristic absorption and emission at excitonic resonances. Due to their extreme flexibility, strain can be used to alter the fundamental exciton energies and line widths of TMDCs. Here, we report on the Stokes shift, i.e. the energetic difference of light absorption and emission, of the A exciton in TMDC mono- and bilayers. We demonstrate that mechanical strain can be used to tune the Stokes shift. We perform optical transmission and photoluminescence (PL) experiments on mono- and bilayers and apply uniaxial tensile strain of up to 1.2% in MoSe2 and WS2 bilayers. An A exciton red shift of -38 meV/% and -70 meV/% is found in transmission in MoSe2 and WS2, while smaller values of -27 meV/% and -62 meV/% are measured in PL, respectively. Therefore, a reduction of the Stokes shift is observed under increasing tensile strain. At the same time, the A exciton PL line widths narrow significantly with -14 meV/% (MoSe2) and -21 meV/% (WS2), demonstrating a drastic change in the exciton-phonon interaction. By comparison with ab initio calculations, we can trace back the observed shifts of the excitons to changes in the electronic band structure of the materials. Variations of the relative energetic positions of the different excitons lead to a decrease of the exciton-phonon coupling. Furthermore, we identify the indirect exciton emission in bilayer WS2 as the ΓK transition by comparing the experimental and theoretical gauge factors.
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Affiliation(s)
- Iris Niehues
- Institute of Physics and Center for Nanotechnology, University of Münster, 48149 Münster, Germany.
| | - Philipp Marauhn
- Institute of Solid State Theory, University of Münster, 48149 Münster, Germany
| | - Thorsten Deilmann
- Institute of Solid State Theory, University of Münster, 48149 Münster, Germany
| | - Daniel Wigger
- Department of Theoretical Physics, Wrocław University of Science and Technology, 50-370 Wrocław, Poland
| | - Robert Schmidt
- Institute of Physics and Center for Nanotechnology, University of Münster, 48149 Münster, Germany.
| | - Ashish Arora
- Institute of Physics and Center for Nanotechnology, University of Münster, 48149 Münster, Germany.
| | | | - Michael Rohlfing
- Institute of Solid State Theory, University of Münster, 48149 Münster, Germany
| | - Rudolf Bratschitsch
- Institute of Physics and Center for Nanotechnology, University of Münster, 48149 Münster, Germany.
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20
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Wang K, Ren K, Cheng Y, Zhang M, Wang H, Zhang G. Effects of molecular adsorption on the spin-wave spectrum and magnon relaxation in two-dimensional Cr 2Ge 2Te 6. Phys Chem Chem Phys 2020; 22:22047-22054. [PMID: 32985620 DOI: 10.1039/d0cp03884a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this work, we performed detailed first-principles calculation and theoretical analysis to investigate the effect of molecular adsorption on the spin-wave spectrum and magnon relaxation in a Cr2Ge2Te6 (CGT) monolayer. It is found that NH3, NO, and NO2 adsorption can enhance the exchange constant of CGT, which can result in a blue-shift in the spin-wave spectrum. At 30 K, by means of a thorough investigation of many possible lattice configurations excited by thermal fluctuation, we identify the magnon scattering rate from the intrinsic lattice vibrational modes, and find that the relaxation of optical and acoustic magnons exhibits a completely different wave vector dependence. Moreover, although the adsorption of NO2 and NH3 molecules has a negligible influence on the magnon-phonon interaction, the adsorption of NO molecules results in a significant increase in magnon scattering strength. In the long-wavelength limit, the interlayer vibrational modes induced by NO adsorption increase the magnon-phonon scattering strength by ∼12.7%. The remarkable interlayer magnon-phonon interaction is ascribed to the strong CGT-NO coupling and large molecular vibration amplitude. Considering the importance of magnon relaxation time in the application of spin devices, we suggest that both the impacts on the exchange interaction and scattering rate must be considered when manipulating two-dimensional magnets by surface functionalization.
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Affiliation(s)
- Ke Wang
- Xidian University, No. 2 Taibai Road, Xi'an, Shaanxi Province 710071, China.
| | - Kai Ren
- School of Mechanical Engineering, Southeast University, Nanjing, Jiangsu 211189, China
| | - Yuan Cheng
- Institute of High Performance Computing, A*STAR, Singapore138632.
| | - Min Zhang
- Xidian University, No. 2 Taibai Road, Xi'an, Shaanxi Province 710071, China.
| | - Hai Wang
- Xidian University, No. 2 Taibai Road, Xi'an, Shaanxi Province 710071, China.
| | - Gang Zhang
- Institute of High Performance Computing, A*STAR, Singapore138632.
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21
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Zhao Q, Wang T, Frisenda R, Castellanos‐Gomez A. Giant Piezoresistive Effect and Strong Bandgap Tunability in Ultrathin InSe upon Biaxial Strain. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:2001645. [PMID: 33101864 PMCID: PMC7578899 DOI: 10.1002/advs.202001645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 06/02/2020] [Indexed: 05/05/2023]
Abstract
The ultrathin nature and dangling bonds free surface of 2D semiconductors allow for significant modifications of their bandgap through strain engineering. Here, thin InSe photodetector devices are biaxially stretched, finding, a strong bandgap tunability upon strain. The applied biaxial strain is controlled through the substrate expansion upon temperature increase and the effective strain transfer from the substrate to the thin InSe is confirmed by Raman spectroscopy. The bandgap change upon biaxial strain is determined through photoluminescence measurements, finding a gauge factor of up to ≈200 meV %-1. The effect of biaxial strain on the electrical properties of the InSe devices is further characterized. In the dark state, a large increase of the current is observed upon applied strain which gives a piezoresistive gauge factor value of ≈450-1000, ≈5-12 times larger than that of other 2D materials and of state-of-the-art silicon strain gauges. Moreover, the biaxial strain tuning of the InSe bandgap also translates in a strain-induced redshift of the spectral response of the InSe photodetectors with ΔE cut-off ≈173 meV at a rate of ≈360 meV %-1 of strain, indicating a strong strain tunability of the spectral bandwidth of the photodetectors.
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Affiliation(s)
- Qinghua Zhao
- State Key Laboratory of Solidification ProcessingNorthwestern Polytechnical UniversityXi'an710072P. R. China
- Key Laboratory of Radiation Detection Materials and DevicesMinistry of Industry and Information TechnologyXi'an710072P. R. China
- Materials Science FactoryInstituto de Ciencia de Materiales de Madrid (ICMM‐CSIC)MadridE‐28049Spain
| | - Tao Wang
- State Key Laboratory of Solidification ProcessingNorthwestern Polytechnical UniversityXi'an710072P. R. China
- Key Laboratory of Radiation Detection Materials and DevicesMinistry of Industry and Information TechnologyXi'an710072P. R. China
| | - Riccardo Frisenda
- Materials Science FactoryInstituto de Ciencia de Materiales de Madrid (ICMM‐CSIC)MadridE‐28049Spain
| | - Andres Castellanos‐Gomez
- Materials Science FactoryInstituto de Ciencia de Materiales de Madrid (ICMM‐CSIC)MadridE‐28049Spain
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Ryu YK, Carrascoso F, López-Nebreda R, Agraït N, Frisenda R, Castellanos-Gomez A. Microheater Actuators as a Versatile Platform for Strain Engineering in 2D Materials. NANO LETTERS 2020; 20:5339-5345. [PMID: 32491864 DOI: 10.1021/acs.nanolett.0c01706] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We present microfabricated thermal actuators to engineer the biaxial strain in two-dimensional (2D) materials. These actuators are based on microheater circuits patterned onto the surface of a polymer with a high thermal expansion coefficient. By running current through the microheater one can vary the temperature of the polymer and induce a controlled biaxial expansion of its surface. This controlled biaxial expansion can be transduced to biaxial strain to 2D materials, placed onto the polymer surface, which in turn induces a shift of the optical spectrum. Our thermal strain actuators can reach a maximum biaxial strain of 0.64%, and they can be modulated at frequencies up to 8 Hz. The compact geometry of these actuators results in a negligible spatial drift of 0.03 μm/°C, which facilitates their integration in optical spectroscopy measurements. We illustrate the potential of this strain engineering platform to fabricate a strain-actuated optical modulator with single-layer MoS2.
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Affiliation(s)
- Yu Kyoung Ryu
- Materials Science Factory, Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), E-28049 Madrid, Spain
| | - Felix Carrascoso
- Materials Science Factory, Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), E-28049 Madrid, Spain
| | - Rubén López-Nebreda
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Nicolás Agraït
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Condensed Matter Physics Center (IFIMAC) and Instituto "Nicolás Cabrera", Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Fundación IMDEA Nanociencia, Ciudad Universitaria de Cantoblanco, E-28049 Madrid, Spain
| | - Riccardo Frisenda
- Materials Science Factory, Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), E-28049 Madrid, Spain
| | - Andres Castellanos-Gomez
- Materials Science Factory, Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), E-28049 Madrid, Spain
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Pacuski W, Grzeszczyk M, Nogajewski K, Bogucki A, Oreszczuk K, Kucharek J, Połczyńska KE, Seredyński B, Rodek A, Bożek R, Taniguchi T, Watanabe K, Kret S, Sadowski J, Kazimierczuk T, Potemski M, Kossacki P. Narrow Excitonic Lines and Large-Scale Homogeneity of Transition-Metal Dichalcogenide Monolayers Grown by Molecular Beam Epitaxy on Hexagonal Boron Nitride. NANO LETTERS 2020; 20:3058-3066. [PMID: 32105481 DOI: 10.1021/acs.nanolett.9b04998] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Monolayer transition-metal dichalcogenides (TMDs) manifest exceptional optical properties related to narrow excitonic resonances. However, these properties have been so far explored only for structures produced by techniques inducing considerable large-scale inhomogeneity. In contrast, techniques which are essentially free from this disadvantage, such as molecular beam epitaxy (MBE), have to date yielded only structures characterized by considerable spectral broadening, which hinders most of the interesting optical effects. Here, we report for the first time on the MBE-grown TMD exhibiting narrow and resolved spectral lines of neutral and charged exciton. Moreover, our material exhibits unprecedented high homogeneity of optical properties, with variation of the exciton energy as small as ±0.16 meV over a distance of tens of micrometers. Our recipe for MBE growth is presented for MoSe2 and includes the use of atomically flat hexagonal boron nitride substrate. This recipe opens a possibility of producing TMD heterostructures with optical quality, dimensions, and homogeneity required for optoelectronic applications.
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Affiliation(s)
- Wojciech Pacuski
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura St. 5, 02-093 Warsaw, Poland
| | - Magdalena Grzeszczyk
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura St. 5, 02-093 Warsaw, Poland
| | - Karol Nogajewski
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura St. 5, 02-093 Warsaw, Poland
| | - Aleksander Bogucki
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura St. 5, 02-093 Warsaw, Poland
| | - Kacper Oreszczuk
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura St. 5, 02-093 Warsaw, Poland
| | - Julia Kucharek
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura St. 5, 02-093 Warsaw, Poland
| | - Karolina E Połczyńska
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura St. 5, 02-093 Warsaw, Poland
| | - Bartłomiej Seredyński
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura St. 5, 02-093 Warsaw, Poland
| | - Aleksander Rodek
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura St. 5, 02-093 Warsaw, Poland
| | - Rafał Bożek
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura St. 5, 02-093 Warsaw, Poland
| | - Takashi Taniguchi
- National Institute for Materials Science, Tsukuba 305-0047, Ibaraki, Japan
| | - Kenji Watanabe
- National Institute for Materials Science, Tsukuba 305-0047, Ibaraki, Japan
| | - Slawomir Kret
- Institute of Physics, Polish Academy of Sciences, al. Lotników 32/46, 02-668 Warsaw, Poland
| | - Janusz Sadowski
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura St. 5, 02-093 Warsaw, Poland
- Institute of Physics, Polish Academy of Sciences, al. Lotników 32/46, 02-668 Warsaw, Poland
- Department of Physics and Electrical Engineering, Linnaeus University, SE-391 82 Kalmar, Sweden
| | - Tomasz Kazimierczuk
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura St. 5, 02-093 Warsaw, Poland
| | - Marek Potemski
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura St. 5, 02-093 Warsaw, Poland
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UJF-UPS-INSA, 25 avenue des Martyrs, 38042 Grenoble, France
| | - Piotr Kossacki
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura St. 5, 02-093 Warsaw, Poland
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24
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Paradisanos I, Shree S, George A, Leisgang N, Robert C, Watanabe K, Taniguchi T, Warburton RJ, Turchanin A, Marie X, Gerber IC, Urbaszek B. Controlling interlayer excitons in MoS 2 layers grown by chemical vapor deposition. Nat Commun 2020; 11:2391. [PMID: 32404912 PMCID: PMC7220905 DOI: 10.1038/s41467-020-16023-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 04/06/2020] [Indexed: 12/18/2022] Open
Abstract
Combining MoS2 monolayers to form multilayers allows to access new functionalities. Deterministic assembly of large area van der Waals structures requires concrete indicators of successful interlayer coupling in bilayers grown by chemical vapor deposition. In this work, we examine the correlation between the stacking order and the interlayer coupling of valence states in both as-grown MoS2 homobilayer samples and in artificially stacked bilayers from monolayers, all grown by chemical vapor deposition. We show that hole delocalization over the bilayer is only allowed in 2H stacking and results in strong interlayer exciton absorption and also in a larger A-B exciton separation as compared to 3R bilayers. Comparing 2H and 3R reflectivity spectra allows to extract an interlayer coupling energy of about t⊥ = 49 meV. Beyond DFT calculations including excitonic effects confirm signatures of efficient interlayer coupling for 2H stacking in agreement with our experiments.
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Affiliation(s)
- Ioannis Paradisanos
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077, Toulouse, France
| | - Shivangi Shree
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077, Toulouse, France
| | - Antony George
- Institute of Physical Chemistry, Friedrich Schiller University Jena, 07743, Jena, Germany
| | - Nadine Leisgang
- Department of Physics, University of Basel, Basel, Switzerland
| | - Cedric Robert
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077, Toulouse, France
| | - Kenji Watanabe
- National Institute for Materials Science, Tsukuba, 305-0044, Ibaraki, Japan
| | - Takashi Taniguchi
- National Institute for Materials Science, Tsukuba, 305-0044, Ibaraki, Japan
| | | | - Andrey Turchanin
- Institute of Physical Chemistry, Friedrich Schiller University Jena, 07743, Jena, Germany
- Abbe Centre of Photonics, 07745, Jena, Germany
| | - Xavier Marie
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077, Toulouse, France
| | - Iann C Gerber
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077, Toulouse, France.
| | - Bernhard Urbaszek
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077, Toulouse, France.
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1T/2H-MoS2 engineered by in-situ ethylene glycol intercalation for improved toluene sensing response at room temperature. ADV POWDER TECHNOL 2020. [DOI: 10.1016/j.apt.2020.02.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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