1
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Awate S, Xu K, Liang J, Katz B, Muzzio R, Crespi VH, Katoch J, Fullerton-Shirey SK. Strain-Induced 2H to 1T' Phase Transition in Suspended MoTe 2 Using Electric Double Layer Gating. ACS NANO 2023; 17:22388-22398. [PMID: 37947443 PMCID: PMC10690768 DOI: 10.1021/acsnano.3c04701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 11/03/2023] [Accepted: 11/06/2023] [Indexed: 11/12/2023]
Abstract
MoTe2 can be converted from the semiconducting (2H) phase to the semimetallic (1T') phase by several stimuli including heat, electrochemical doping, and strain. This type of phase transition, if reversible and gate-controlled, could be useful for low-power memory and logic. In this work, a gate-controlled and fully reversible 2H to 1T' phase transition is demonstrated via strain in few-layer suspended MoTe2 field effect transistors. Strain is applied by the electric double layer gating of a suspended channel using a single ion conducting solid polymer electrolyte. The phase transition is confirmed by simultaneous electrical transport and Raman spectroscopy. The out-of-plane vibration peak (A1g)─a signature of the 1T' phase─is observed when VSG ≥ 2.5 V. Further, a redshift in the in-plane vibration mode (E2g) is detected, which is a characteristic of a strain-induced phonon shift. Based on the magnitude of the shift, strain is estimated to be 0.2-0.3% by density functional theory. Electrically, the temperature coefficient of resistance transitions from negative to positive at VSG ≥ 2 V, confirming the transition from semiconducting to metallic. The approach to gate-controlled, reversible straining presented here can be extended to strain other two-dimensional materials, explore fundamental material properties, and introduce electronic device functionalities.
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Affiliation(s)
- Shubham
Sukumar Awate
- Department
of Chemical and Petroleum Engineering, University
of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Ke Xu
- Department
of Chemical and Petroleum Engineering, University
of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
- School
of Physics and Astronomy, Rochester Institute
of Technology, Rochester, New York 14623, United States
- Microsystems
Engineering, Rochester Institute of Technology, Rochester, New York 14623, United States
| | - Jierui Liang
- Department
of Chemical and Petroleum Engineering, University
of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Benjamin Katz
- Department
of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Ryan Muzzio
- Department
of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Vincent H. Crespi
- Department
of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department
of Materials Science and Engineering, The
Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department
of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Jyoti Katoch
- Department
of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Susan K. Fullerton-Shirey
- Department
of Chemical and Petroleum Engineering, University
of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
- Department
of Electrical and Computer Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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2
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Aftab S, Shehzad MA, Salman Ajmal HM, Kabir F, Iqbal MZ, Al-Kahtani AA. Bulk Photovoltaic Effect in Two-Dimensional Distorted MoTe 2. ACS NANO 2023; 17:17884-17896. [PMID: 37656985 DOI: 10.1021/acsnano.3c03593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/03/2023]
Abstract
In future solar cell technologies, the thermodynamic Shockley-Queisser limit for solar-to-current conversion in traditional p-n junctions could potentially be overcome with a bulk photovoltaic effect by creating an inversion broken symmetry in piezoelectric or ferroelectric materials. Here, we unveiled mechanical distortion-induced bulk photovoltaic behavior in a two-dimensional (2D) material, MoTe2, caused by the phase transition and broken inversion symmetry in MoTe2. The phase transition from single-crystalline semiconducting 2H-MoTe2 to semimetallic 1T'-MoTe2 was confirmed using X-ray photoelectron spectroscopy (XPS). We used a micrometer-scale system to measure the absorption of energy, which reduced from 800 to 63 meV during phase transformation from hexagonal to distorted octahedral and revealed a smaller bandgap semimetallic behavior. Experimentally, a large bulk photovoltaic response is anticipated with the maximum photovoltage VOC = 16 mV and a positive signal of the ISC = 60 μA (400 nm, 90.4 Wcm-2) in the absence of an external electric field. The maximum values of both R and EQE were found to be 98 mAW-1 and 30%, respectively. Our findings are distinctive features of the photocurrent responses caused by in-plane polarity and its potential from a wide pool of established TMD-based nanomaterials and a cutting-edge approach to optimize the efficiency in converting photons-to-electricity for power harvesting optoelectronics devices.
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Affiliation(s)
- Sikandar Aftab
- Department of Intelligent Mechatronics Engineering, Sejong University, Seoul 05006, South Korea
| | - Muhammad Arslan Shehzad
- Northwestern University Atomic and Nanoscale Characterization Experimental (NUANCE) Center, Northwestern University, Evanston, Illinois 60208, United States
| | - Hafiz Muhammad Salman Ajmal
- Department of Biomedical Engineering, Narowal Campus-University of Engineering and Technology, Lahore 54890, Pakistan
| | - Fahmid Kabir
- School of Engineering Science, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Muhammad Zahir Iqbal
- Nanotechnology Research Laboratory, Faculty of Engineering Sciences, GIK Institute of Engineering Sciences and Technology, Topi, Khyber Pakhtunkhwa 23640, Pakistan
| | - Abdullah A Al-Kahtani
- Chemistry Department, Collage of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
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3
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Wang S, Yang T, Kumar K, Namvar S, Kim S, Ahmadiparidari A, Shahbazi H, Singh S, Hemmat Z, Berry V, Cabana J, Khalili-Araghi F, Huang Z, Salehi-Khojin A. Thermodynamics and Kinetics in Anisotropic Growth of One-Dimensional Midentropy Nanoribbons. ACS NANO 2023. [PMID: 37467377 DOI: 10.1021/acsnano.3c04178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/21/2023]
Abstract
One-dimensional (1D) materials demonstrate anisotropic in-plane physical properties that enable a wide range of functionalities in electronics, photonics, valleytronics, optoelectronics, and catalysis. Here, we undertake an in-depth study of the growth mechanism for equimolar midentropy alloy of (NbTaTi)0.33S3 nanoribbons as a model system for 1D transition metal trichalcogenide structures. To understand the thermodynamic and kinetic effects in the growth process, the energetically preferred phases at different synthesis temperatures and times are investigated, and the phase evolution is inspected at a sequence of growth steps. It is uncovered that the dynamics of the growth process occurs at four different stages via preferential incorporation of chemical species at high-surface-energy facets. Also, a sequence of temperature and time dependent nonuniform to uniform phase evolutions has emerged in the composition and structure of (NbTaTi)0.33S3 which is described based on an anisotropic vapor-solid (V-S) mechanism. Furthermore, direct evidence for the 3D structure of the charge density wave (CDW) phase (width less than 100 nm) is provided by three-dimensional electron diffraction (3DED) in individual nanoribbons at cryogenic temperature, and detailed comparisons are made between the phases obtained before and after CDW transformation. This study provides important fundamental information for the design and synthesis of future 1D alloy structures.
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Affiliation(s)
- Shuxi Wang
- Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Taimin Yang
- Department of Materials and Environmental Chemistry, Stockholm University, Stockholm 10691, Sweden
| | - Khagesh Kumar
- Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Shahriar Namvar
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Sungjoon Kim
- Department of Chemical Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Alireza Ahmadiparidari
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Hessam Shahbazi
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Sakshi Singh
- Department of Chemical Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Zahra Hemmat
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Vikas Berry
- Department of Chemical Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Jordi Cabana
- Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Fatemeh Khalili-Araghi
- Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Zhehao Huang
- Department of Materials and Environmental Chemistry, Stockholm University, Stockholm 10691, Sweden
| | - Amin Salehi-Khojin
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, United States
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4
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Vikraman D, Hussain S, Abbas Z, Karuppasamy K, Santhoshkumar P, Jung J, Kim HS. Density Functional Theory Approximations and Experimental Investigations on Co 1-xMo xTe 2 Alloy Electrocatalysts Tuning the Overall Water Splitting Reactions. ACS APPLIED MATERIALS & INTERFACES 2023. [PMID: 37229631 DOI: 10.1021/acsami.3c05055] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Understanding the relationship between electronic structure, surface characteristic, and reaction process of a catalyst helps to architect proficient electrodes for sustainable energy development. The highly active and stable catalysts made of earth-abundant materials provide a great endeavor toward green hydrogen production. Herein, we assembled the Co1-xMoxTe (x = 0-1) nanoarray structures into a bifunctional electrocatalyst to achieve high-performance hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) kinetics under alkaline conditions. The designed Co0.75Mo0.25Te and Co0.50Mo0.50 electrocatalysts require minimum overpotential and Tafel slope for high-efficacy HER and OER, respectively. Furthermore, we constructed a Co0.50Mo0.50Te2∥Co0.50Mo0.50Te2 device for overall water splitting with an overpotential of 1.39 V to achieve a current density of 10 mA cm-2, which is superior to noble electrocatalyst performance, with stable reaction throughout the 50 h continuous process. Density functional theory approximations and Gibbs free energy calculations validate the enhanced water splitting reaction catalyzed by the Co0.50Mo0.50Te2 nanoarrays. The partial replacement of Co atoms with Mo atoms in the Co0.50Mo0.50Te2 structure substantially enhances the water electrolysis kinetics through the synergistic effects between the combined metal atoms and the bonded chalcogen.
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Affiliation(s)
- Dhanasekaran Vikraman
- Division of Electronics and Electrical Engineering, Dongguk University-Seoul, Seoul 04620, Republic of Korea
| | - Sajjad Hussain
- Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 05006, Republic of Korea
- Hybrid Materials Center (HMC), Sejong University, Seoul 05006, Republic of Korea
| | - Zeesham Abbas
- Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 05006, Republic of Korea
| | - K Karuppasamy
- Division of Electronics and Electrical Engineering, Dongguk University-Seoul, Seoul 04620, Republic of Korea
| | - P Santhoshkumar
- Millimeter-Wave Innovation Technology (MINT) Research Centre, Dongguk University-Seoul, Seoul 04620, Republic of Korea
| | - Jongwan Jung
- Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 05006, Republic of Korea
- Hybrid Materials Center (HMC), Sejong University, Seoul 05006, Republic of Korea
| | - Hyun-Seok Kim
- Division of Electronics and Electrical Engineering, Dongguk University-Seoul, Seoul 04620, Republic of Korea
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5
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Kowalczyk H, Biscaras J, Pistawala N, Harnagea L, Singh S, Shukla A. Gate and Temperature Driven Phase Transitions in Few-Layer MoTe 2. ACS NANO 2023; 17:6708-6718. [PMID: 36972180 DOI: 10.1021/acsnano.2c12610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
MoTe2 has a stable hexagonal semiconducting phase (2H) as well as two semimetallic phases with monoclinic (1T') and orthorhombic (Td) structures. A structural change can thus be accompanied by a significant change in electronic transport properties. The two semimetallic phases are connected by a temperature driven transition and could exhibit topological properties. Here we make extensive Raman measurements as a function of layer thickness, temperature, and electrostatic doping on few layer 2H-MoTe2 and also on 1T'-MoTe2 and Td-WTe2. Recent work in MoTe2 has raised the possibility of a 2H-1T' transition through technology compatible pathways. It has been claimed that such a transition, of promise for device applications, is activated by electrostatic gating. We investigate this claim and find that few-layer tellurides are characterized by high mobility of Te ions, even in ambient conditions and especially through the variation of external parameters like electric field or temperature. These can generate Te clusters, vacancies at crystalline sites, and facilitate structural transitions. We however find that the purported 2H-1T' transition in MoTe2 cannot be obtained by a pure electrostatic field.
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Affiliation(s)
- Hugo Kowalczyk
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, 75005 Paris, France
| | - Johan Biscaras
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, 75005 Paris, France
| | - Nashra Pistawala
- Department of Physics, Indian Institute of Science Education and Research, Pune, Maharashtra 411008, India
| | - Luminita Harnagea
- Department of Physics, Indian Institute of Science Education and Research, Pune, Maharashtra 411008, India
| | - Surjeet Singh
- Department of Physics, Indian Institute of Science Education and Research, Pune, Maharashtra 411008, India
| | - Abhay Shukla
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, 75005 Paris, France
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6
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Aftab S, Hegazy HH, Iqbal MZ. Recent advances in 2D TMD circular photo-galvanic effects. NANOSCALE 2023; 15:3651-3665. [PMID: 36734944 DOI: 10.1039/d2nr05337c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Two-dimensional (2D) layered semiconductors are appealing materials for high-specific-power photovoltaic systems due to their unique optoelectronic properties. The 2D materials can be naturally thin, and their properties can be altered in a variety of ways. Therefore, these materials may be used to develop high-performance opto-spintronic and photovoltaic devices. The most recent and promising strategies were used to induce circular photo-galvanic effects (CPGEs) in 2D TMD materials with broken inversion symmetry. The majority of quantum devices were manufactured by mechanical exfoliation to investigate the electrical behavior of ultrathin 2D materials. The investigation of CPGEs in 2D materials could enable the exploration of spin-polarized optoelectronics to produce more energy-efficient computing systems. The current research on nanomaterial-based materials paves the way for developing materials to store, manipulate, and transmit information with better performance. Finally, this study concludes by summarizing the current challenges and prospects.
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Affiliation(s)
- Sikandar Aftab
- Department of Intelligent Mechatronics Engineering, Sejong University, Seoul 05006, South Korea.
| | - Hosameldin Helmy Hegazy
- Research Center for Advanced Materials Science (RCAMS), King Khalid University, Abha 61413, P. O. Box 9004, Saudi Arabia
- Department of Physics, Faculty of Science, King Khalid University, P.O. Box 9004, Abha, Saudi Arabia
| | - Muhammad Zahir Iqbal
- Faculty of Engineering Sciences, Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi 23640, Khyber Pakhtunkhwa, Pakistan
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7
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Lacinska EM, Furman M, Binder J, Lutsyk I, Kowalczyk PJ, Stepniewski R, Wysmolek A. Raman Optical Activity of 1T-TaS 2. NANO LETTERS 2022; 22:2835-2842. [PMID: 35369696 PMCID: PMC9011401 DOI: 10.1021/acs.nanolett.1c04990] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Measurements of optical activity can be readily performed in transparent matter by means of a rotation of transmitted light polarization. In the case of opaque bulk materials, such measurements cannot be performed, making it difficult to assess possible chiral properties. In this work, we present full angular polarization dependencies of the Raman modes of bulk 1T-TaS2, which has recently been suggested to have chiral properties after pulsed laser excitation. We found that a mechanical rotation of the sample does not alter polarization-resolved Raman spectra, which can only be explained by introducing an antisymmetric Raman tensor, frequently used to describe Raman optical activity (ROA). Raman spectra obtained under circularly polarized excitation demonstrate that 1T-TaS2 indeed shows ROA, providing strong evidence that 1T-TaS2 is chiral under the used conditions of laser excitation. Our results suggest that ROA may be used as a universal tool to study chiral properties of quantum materials.
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Affiliation(s)
- Ewa M. Lacinska
- Faculty
of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - Magdalena Furman
- Faculty
of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - Johannes Binder
- Faculty
of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - Iaroslav Lutsyk
- Faculty
of Physics and Applied Informatics, University
of Lodz, Pomorska 149/153, 90-236 Lodz, Poland
| | - Pawel J. Kowalczyk
- Faculty
of Physics and Applied Informatics, University
of Lodz, Pomorska 149/153, 90-236 Lodz, Poland
| | - Roman Stepniewski
- Faculty
of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - Andrzej Wysmolek
- Faculty
of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
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8
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Su B, Huang Y, Hou YH, Li J, Yang R, Ma Y, Yang Y, Zhang G, Zhou X, Luo J, Chen Z. Persistence of Monoclinic Crystal Structure in 3D Second-Order Topological Insulator Candidate 1T'-MoTe 2 Thin Flake Without Structural Phase Transition. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2101532. [PMID: 34923770 PMCID: PMC8844473 DOI: 10.1002/advs.202101532] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 10/29/2021] [Indexed: 05/29/2023]
Abstract
A van der Waals material, MoTe2 with a monoclinic 1T' crystal structure is a candidate for 3D second-order topological insulators (SOTIs) hosting gapless hinge states and insulating surface states. However, due to the temperature-induced structural phase transition, the monoclinic 1T' structure of MoTe2 is transformed into the orthorhombic Td structure as the temperature is lowered, which hinders the experimental verification and electronic applications of the predicted SOTI state at low temperatures. Here, systematic Raman spectroscopy studies of the exfoliated MoTe2 thin flakes with variable thicknesses at different temperatures, are presented. As a spectroscopic signature of the orthorhombic Td structure of MoTe2 , the out-of-plane vibration mode D at ≈ 125 cm-1 is always visible below a certain temperature in the multilayer flakes thicker than ≈ 27.7 nm, but vanishes in the temperature range from 80 to 320 K when the flake thickness becomes lower than ≈ 19.5 nm. The absence of the out-of-plane vibration mode D in the Raman spectra here demonstrates not only the disappearance of the monoclinic-to-orthorhombic phase transition but also the persistence of the monoclinic 1T' structure in the MoTe2 thin flakes thinner than ≈ 19.5 nm at low temperatures down to 80 K, which may be caused by the high enough density of the holes introduced during the gold-enhanced exfoliation process and exposure to air. The MoTe2 thin flakes with the low-temperature monoclinic 1T' structure provide a material platform for realizing SOTI states in van der Waals materials at low temperatures, which paves the way for developing a new generation of electronic devices based on SOTIs.
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Affiliation(s)
- Bo Su
- Beijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of SciencesBeijing100190China
- School of Physical SciencesUniversity of Chinese Academy of SciencesBeijing100190China
| | - Yuan Huang
- Beijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of SciencesBeijing100190China
- Songshan Lake Materials LaboratoryDongguan523808China
| | - Yan Hui Hou
- Beijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of SciencesBeijing100190China
- School of Materials Science and EngineeringTianjin University of TechnologyTianjin300384China
| | - Jiawei Li
- Beijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of SciencesBeijing100190China
- School of Physical SciencesUniversity of Chinese Academy of SciencesBeijing100190China
| | - Rong Yang
- Beijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of SciencesBeijing100190China
- Songshan Lake Materials LaboratoryDongguan523808China
| | - Yongchang Ma
- School of Materials Science and EngineeringTianjin University of TechnologyTianjin300384China
| | - Yang Yang
- Beijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of SciencesBeijing100190China
- Songshan Lake Materials LaboratoryDongguan523808China
| | - Guangyu Zhang
- Beijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of SciencesBeijing100190China
- School of Physical SciencesUniversity of Chinese Academy of SciencesBeijing100190China
- Songshan Lake Materials LaboratoryDongguan523808China
- Collaborative Innovation Center of Quantum MatterBeijingChina
| | - Xingjiang Zhou
- Beijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of SciencesBeijing100190China
- School of Physical SciencesUniversity of Chinese Academy of SciencesBeijing100190China
- Songshan Lake Materials LaboratoryDongguan523808China
- Collaborative Innovation Center of Quantum MatterBeijingChina
| | - Jianlin Luo
- Beijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of SciencesBeijing100190China
- School of Physical SciencesUniversity of Chinese Academy of SciencesBeijing100190China
- Songshan Lake Materials LaboratoryDongguan523808China
- Collaborative Innovation Center of Quantum MatterBeijingChina
| | - Zhi‐Guo Chen
- Beijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of SciencesBeijing100190China
- School of Physical SciencesUniversity of Chinese Academy of SciencesBeijing100190China
- Songshan Lake Materials LaboratoryDongguan523808China
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9
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Deng Y, Li P, Zhu C, Zhou J, Wang X, Cui J, Yang X, Tao L, Zeng Q, Duan R, Fu Q, Zhu C, Xu J, Qu F, Yang C, Jing X, Lu L, Liu G, Liu Z. Controlled Synthesis of Mo xW 1-xTe 2 Atomic Layers with Emergent Quantum States. ACS NANO 2021; 15:11526-11534. [PMID: 34162202 DOI: 10.1021/acsnano.1c01441] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Recently, new states of matter like superconducting or topological quantum states were found in transition metal dichalcogenides (TMDs) and manifested themselves in a series of exotic physical behaviors. Such phenomena have been demonstrated to exist in a series of transition metal tellurides including MoTe2, WTe2, and alloyed MoxW1-xTe2. However, the behaviors in the alloy system have been rarely addressed due to their difficulty in obtaining atomic layers with controlled composition, albeit the alloy offers a great platform to tune the quantum states. Here, we report a facile CVD method to synthesize the MoxW1-xTe2 with controllable thickness and chemical composition ratios. The atomic structure of a monolayer MoxW1-xTe2 alloy was experimentally confirmed by scanning transmission electron microscopy. Importantly, two different transport behaviors including superconducting and Weyl semimetal states were observed in Mo-rich Mo0.8W0.2Te2 and W-rich Mo0.2W0.8Te2 samples, respectively. Our results show that the electrical properties of MoxW1-xTe2 can be tuned by controlling the chemical composition, demonstrating our controllable CVD growth method is an efficient strategy to manipulate the physical properties of TMDCs. Meanwhile, it provides a perspective on further comprehension and sheds light on the design of devices with topological multicomponent TMDC materials.
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Affiliation(s)
- Ya Deng
- School of Materials Science & Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Peiling Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chao Zhu
- School of Materials Science & Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Jiadong Zhou
- School of Materials Science & Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Xiaowei Wang
- School of Materials Science & Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Jian Cui
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xue Yang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Li Tao
- Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Qingsheng Zeng
- School of Materials Science & Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Ruihuan Duan
- School of Materials Science & Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Qundong Fu
- School of Materials Science & Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Chao Zhu
- School of Materials Science & Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Jianbin Xu
- Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Fanming Qu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Changli Yang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiunian Jing
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Li Lu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Guangtong Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Zheng Liu
- CINTRA CNRS/NTU/THALES, UMI 3288, Singapore 637553, Singapore
- School of Materials Science and Engineering, School of Physical and Mathematical Science and School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, Singapore
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10
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Cheon Y, Lim SY, Kim K, Cheong H. Structural Phase Transition and Interlayer Coupling in Few-Layer 1T' and T d MoTe 2. ACS NANO 2021; 15:2962-2970. [PMID: 33480685 DOI: 10.1021/acsnano.0c09162] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We performed polarized Raman spectroscopy on mechanically exfoliated few-layer MoTe2 samples and observed both 1T' and Td phases at room temperature. Few-layer 1T' and Td MoTe2 exhibited a significant difference especially in interlayer vibration modes, from which the interlayer coupling strengths were extracted using the linear chain model: strong in-plane anisotropy was observed in both phases. Furthermore, temperature-dependent Raman measurements revealed a peculiar phase transition behavior in few-layer 1T' MoTe2. In contrast to bulk 1T' MoTe2 crystals, where the phase transition to the Td phase occurs at ∼250 K, the temperature-driven phase transition to the Td phase is increasingly suppressed as the thickness is reduced, and the transition and the critical temperature varied dramatically from sample to sample even for the same thickness. Raman spectra of intermediate phases that correspond to neither 1T' nor Td phase with different interlayer vibration modes were observed, which suggests that several metastable phases exist with similar total energies.
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Affiliation(s)
- Yeryun Cheon
- Department of Physics, Sogang University, Seoul 04107, Korea
| | - Soo Yeon Lim
- Department of Physics, Sogang University, Seoul 04107, Korea
| | - Kangwon Kim
- Department of Physics, Sogang University, Seoul 04107, Korea
| | - Hyeonsik Cheong
- Department of Physics, Sogang University, Seoul 04107, Korea
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11
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Ge R, Wu X, Liang L, Hus SM, Gu Y, Okogbue E, Chou H, Shi J, Zhang Y, Banerjee SK, Jung Y, Lee JC, Akinwande D. A Library of Atomically Thin 2D Materials Featuring the Conductive-Point Resistive Switching Phenomenon. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2007792. [PMID: 33368706 DOI: 10.1002/adma.202007792] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Indexed: 06/12/2023]
Abstract
Non-volatile resistive switching (NVRS) is a widely available effect in transitional metal oxides, colloquially known as memristors, and of broad interest for memory technology and neuromorphic computing. Until recently, NVRS was not known in other transitional metal dichalcogenides (TMDs), an important material class owing to their atomic thinness enabling the ultimate dimensional scaling. Here, various monolayer or few-layer 2D materials are presented in the conventional vertical structure that exhibit NVRS, including TMDs (MX2 , M = transitional metal, e.g., Mo, W, Re, Sn, or Pt; X = chalcogen, e.g., S, Se, or Te), TMD heterostructure (WS2 /MoS2 ), and an atomically thin insulator (h-BN). These results indicate the universality of the phenomenon in 2D non-conductive materials, and feature low switching voltage, large ON/OFF ratio, and forming-free characteristic. A dissociation-diffusion-adsorption model is proposed, attributing the enhanced conductance to metal atoms/ions adsorption into intrinsic vacancies, a conductive-point mechanism supported by first-principle calculations and scanning tunneling microscopy characterizations. The results motivate further research in the understanding and applications of defects in 2D materials.
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Affiliation(s)
- Ruijing Ge
- Microelectronics Research Center, The University of Texas at Austin, Austin, TX, 78758, USA
| | - Xiaohan Wu
- Microelectronics Research Center, The University of Texas at Austin, Austin, TX, 78758, USA
| | - Liangbo Liang
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Saban M Hus
- Microelectronics Research Center, The University of Texas at Austin, Austin, TX, 78758, USA
| | - Yuqian Gu
- Microelectronics Research Center, The University of Texas at Austin, Austin, TX, 78758, USA
| | - Emmanuel Okogbue
- Nanoscience Technology Center and Department of Electrical Engineering, University of Central Florida, Orlando, FL, 32826, USA
| | - Harry Chou
- Microelectronics Research Center, The University of Texas at Austin, Austin, TX, 78758, USA
| | - Jianping Shi
- Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing, 100871, China
- The Institute for Advanced Studies, Wuhan University, Wuhan, 430072, China
| | - Yanfeng Zhang
- Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing, 100871, China
| | - Sanjay K Banerjee
- Microelectronics Research Center, The University of Texas at Austin, Austin, TX, 78758, USA
| | - Yeonwoong Jung
- Nanoscience Technology Center and Department of Electrical Engineering, University of Central Florida, Orlando, FL, 32826, USA
- Department of Materials Science and Technology, University of Central Florida, Orlando, FL, 32816, USA
| | - Jack C Lee
- Microelectronics Research Center, The University of Texas at Austin, Austin, TX, 78758, USA
| | - Deji Akinwande
- Microelectronics Research Center, The University of Texas at Austin, Austin, TX, 78758, USA
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12
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Das S, Debnath K, Chakraborty B, Singh A, Grover S, Muthu DVS, Waghmare UV, Sood AK. Symmetry induced phonon renormalization in few layers of 2H-MoTe 2 transistors: Raman and first-principles studies. NANOTECHNOLOGY 2021; 32:045202. [PMID: 33036010 DOI: 10.1088/1361-6528/abbfd6] [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
Understanding of electron-phonon coupling (EPC) in two-dimensional (2D) materials manifesting as phonon renormalization is essential to their possible applications in nanoelectronics. Here we report in situ Raman measurements of electrochemically top-gated 2, 3 and 7 layered 2H-MoTe2 channel based field-effect transistors. While the [Formula: see text] and B2g phonon modes exhibit frequency softening and linewidth broadening with hole doping concentration (p) up to ∼2.3 × 1013/cm2, A1g shows relatively small frequency hardening and linewidth sharpening. The dependence of frequency renormalization of the [Formula: see text] mode on the number of layers in these 2D crystals confirms that hole doping occurs primarily in the top two layers, in agreement with recent predictions. We present first-principles density functional theory analysis of bilayer MoTe2 that qualitatively captures our observations, and explain that a relatively stronger coupling of holes with [Formula: see text] or B2g modes as compared with the A1g mode originates from the in-plane orbital character and symmetry of the states at valence band maximum. The contrast between the manifestation of EPC in monolayer MoS2 and those observed here in a few-layered MoTe2 demonstrates the role of the symmetry of phonons and electronic states in determining the EPC in these isostructural systems.
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Affiliation(s)
- Subhadip Das
- Department of Physics, Indian Institute of Science, Bangalore 560012, India
| | - Koyendrila Debnath
- Theoretical Sciences Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore-560064, India
| | | | - Anjali Singh
- Center for Study of Science, Technology & Policy (CSTEP), Bangalore 560094, India
| | - Shivani Grover
- Theoretical Sciences Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore-560064, India
| | - D V S Muthu
- Department of Physics, Indian Institute of Science, Bangalore 560012, India
| | - U V Waghmare
- Theoretical Sciences Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore-560064, India
| | - A K Sood
- Department of Physics, Indian Institute of Science, Bangalore 560012, India
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13
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Xu X, Han B, Liu S, Yang S, Jia X, Xu W, Gao P, Ye Y, Dai L. Atomic-Precision Repair of a Few-Layer 2H-MoTe 2 Thin Film by Phase Transition and Recrystallization Induced by a Heterophase Interface. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2000236. [PMID: 32329549 DOI: 10.1002/adma.202000236] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 03/26/2020] [Accepted: 04/02/2020] [Indexed: 06/11/2023]
Abstract
2D semiconductors have emerged as promising candidates for post-silicon nanoelectronics, owing to their unique properties and atomic thickness. However, in the handling of 2D material, various forms of macroscopic damage, such as cracks, wrinkles, and scratches, etc., are usually introduced, which cause adverse effects on the material properties and device performance. Repairing such macroscopic damage is crucial for improving device performance and reliability, especially for large-scale 2D device arrays. Here, a method is demonstrated repair damage to few-layer 2H-MoTe2 films with atomic precision, and its mechanism is elucidated. The repaired 2H-MoTe2 inherits the lattice orientation of the adjacent original 2H-MoTe2 , thereby forming an atomically perfect lattice at the repaired interface. The time-evolution experiments show that the interface between the 2H- and early formed 1T'-MoTe2 plays an important role in the subsequent phase transition and recrystallization. Electrical measurements on the original MoTe2 , repaired MoTe2 , and cross-interface regions show unobservable differences, indicating that the repaired MoTe2 has the same electrical quality as the original one and the interface does not introduce extra scattering centers for carrier transport. The findings provide an effective strategy for macroscopic damage repair of few-layer 2H-MoTe2 , which paves the way for its practical application in advanced electronics and optoelectronics.
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Affiliation(s)
- Xiaolong Xu
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing, 100871, China
| | - Bo Han
- Electron Microscopy Laboratory and International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, China
| | - Shuai Liu
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing, 100871, China
| | - Shiqi Yang
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing, 100871, China
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China
| | - Xionghui Jia
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing, 100871, China
| | - Wanjin Xu
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing, 100871, China
| | - Peng Gao
- Electron Microscopy Laboratory and International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, China
- Collaborative Innovation Center of Quantum Matter, Beijing, 100871, China
| | - Yu Ye
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing, 100871, China
- Collaborative Innovation Center of Quantum Matter, Beijing, 100871, China
| | - Lun Dai
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing, 100871, China
- Collaborative Innovation Center of Quantum Matter, Beijing, 100871, China
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14
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Yu J, Kuang X, Gao Y, Wang Y, Chen K, Ding Z, Liu J, Cong C, He J, Liu Z, Liu Y. Direct Observation of the Linear Dichroism Transition in Two-Dimensional Palladium Diselenide. NANO LETTERS 2020; 20:1172-1182. [PMID: 31944114 DOI: 10.1021/acs.nanolett.9b04598] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The linear dichroism (LD) transition within anisotropic photonic materials displays promising prospects for applications in polarization-wavelength-selective detectors, optical switching, and optical communication. In conventional two-dimensional (2D) anisotropic materials, the LD is predominantly uniaxial over a broad spectrum of wavelengths and arises principally from the reduced symmetry of the materials. However, the LD transition behavior in crystalline 2D materials remains elusive. Here, we demonstrate the observation of a unique LD conversion phenomenon at a wavelength of 472 nm in palladium diselenide (PdSe2) using polarization-resolved absorption spectroscopy. This material exhibits prominent anisotropic responses and a high absorption ratio of αy/αx ≈ 1.11 at 364 nm, 1.15 at 532 nm, and 0.84 at 633 nm. We propose that this abnormal LD conversion behavior originates from the forceful localization rules at different parallel energy bands that exist within this material. Furthermore, the robust periodicity of Ag and B1g modes in polarization-resolved Raman spectroscopy is in good agreement with the theoretical structure symmetry analysis. This indicates the strong intrinsic LD effect in the anisotropic nature of PdSe2, which offers a macrolevel determination of crystal orientations. Such unique LD conversion features, in combination with strong LD effects, enable the air-stable PdSe2 to be a potential candidate for technological innovations in multispectral imaging, sensing, and polarization-sensitive and wavelength-controllable photoelectronic applications.
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Affiliation(s)
- Juan Yu
- School of Physics and Electronics, Hunan Key Laboratory for Super-microstructure and Ultrafast Process , Central South University , 932 South Lushan Road , Changsha , Hunan 410083 , People's Republic of China
- School of Electronics and Information , Hangzhou Dianzi University , 1158 Second Street, Xiasha College Park , Hangzhou , Zhejiang 310018 , People's Republic of China
| | - Xiaofei Kuang
- School of Electronics and Information , Hangzhou Dianzi University , 1158 Second Street, Xiasha College Park , Hangzhou , Zhejiang 310018 , People's Republic of China
| | - Yuanji Gao
- School of Physics and Electronics, Hunan Key Laboratory for Super-microstructure and Ultrafast Process , Central South University , 932 South Lushan Road , Changsha , Hunan 410083 , People's Republic of China
| | - Yunpeng Wang
- School of Physics and Electronics, Hunan Key Laboratory for Super-microstructure and Ultrafast Process , Central South University , 932 South Lushan Road , Changsha , Hunan 410083 , People's Republic of China
| | - Keqiu Chen
- Department of Applied Physics, School of Physics and Electronics , Hunan University , Changsha 410082 , People's Republic of China
| | - Zhongke Ding
- Department of Applied Physics, School of Physics and Electronics , Hunan University , Changsha 410082 , People's Republic of China
| | - Jia Liu
- Gemmological Institute , China University of Geoscience , Wuhan 430074 , People's Republic of China
| | - Chunxiao Cong
- School of Information Science and Technology , Fudan University , Shanghai 200433 , People's Republic of China
| | - Jun He
- School of Physics and Electronics, Hunan Key Laboratory for Super-microstructure and Ultrafast Process , Central South University , 932 South Lushan Road , Changsha , Hunan 410083 , People's Republic of China
| | - Zongwen Liu
- School of Chemical and Biomolecular Engineering , The University of Sydney , Darlington NSW 2008 , Australia
| | - Yanping Liu
- School of Physics and Electronics, Hunan Key Laboratory for Super-microstructure and Ultrafast Process , Central South University , 932 South Lushan Road , Changsha , Hunan 410083 , People's Republic of China
- Shenzhen Research Institute of Central South University , A510a, Virtual University Building, Southern District, High-Tech Industrial Park, Yuehai Street, Nanshan District , Shenzhen , People's Republic of China
- State Key Laboratory of High Performance Complex Manufacturing , Central South University , 932 South Lushan Road , Changsha , Hunan 410083 , People's Republic of China
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15
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Tu H, Zhang J, Guo Z, Xu C. Biaxial strain modulated the electronic structure of hydrogenated 2D tetragonal silicene. RSC Adv 2019; 9:42245-42251. [PMID: 35542882 PMCID: PMC9076574 DOI: 10.1039/c9ra08634j] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 12/16/2019] [Indexed: 11/21/2022] Open
Abstract
Silicene-based materials have attracted great attention due to their easier incorporation into silicon-based devices and components. In addition to the reported hydrogenated 2D tetragonal silicene (γ-SiH), we propose two stable atomic configurations of hydrogenated 2D tetragonal silicene (α-SiH and β-SiH) based on first-principles calculation. The calculated results indicate hydrogenation can effectively open the band gap of 2D tetragonal silicene, α-SiH is a semiconductor with a direct band gap of 2.436 eV whereas β-SiH is indirect band gap of 2.286 eV. We also find that the electronic band structure of α-SiH, β-SiH and γ-SiH can be modulated via biaxial strain. By applying biaxial strain in the range of -10% to 12%, the band gap of α-SiH, β-SiH and γ-SiH can be tuned in a range of 1.732-2.585 eV. Furthermore, direct-indirect or indirect-direct transition can be induced under biaxial strain, showing a high degree of flexibility in electronic band structure. The research not only broadens the diversity of hydrogenated 2D tetragonal silicenes, but also provides more possibilities of their applications in spintronic devices.
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Affiliation(s)
- Haoran Tu
- Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), Department of Physics, Jilin University Changchun 130012 China
| | - Jing Zhang
- Institute for Interdisciplinary Quantum Information Technology, Jilin Engineering Normal University Changchun 130052 China
| | - Zexuan Guo
- Institute for Interdisciplinary Quantum Information Technology, Jilin Engineering Normal University Changchun 130052 China
| | - Chunyan Xu
- Institute for Interdisciplinary Quantum Information Technology, Jilin Engineering Normal University Changchun 130052 China
- Jilin Engineering Laboratory for Quantum Information Technology Changchun 130052 China
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16
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Zheng Q, Ren P, Peng Y, Zhou W, Yin Y, Wu H, Gong W, Wang W, Tang D, Zou B. In-Plane Anisotropic Raman Response and Electrical Conductivity with Robust Electron-Photon and Electron-Phonon Interactions of Air Stable MoO 2 Nanosheets. J Phys Chem Lett 2019; 10:2182-2190. [PMID: 30925055 DOI: 10.1021/acs.jpclett.9b00455] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The monoclinic m-MoO2 shows strong in-plane anisotropy that is essential to design anisotropic nanodevices. However, there is not yet detailed study on the anisotropy of m-MoO2 nanostructures. Here, the in-plane anisotropic Raman spectra and electrical conductivity of single-crystal m-MoO2 nanosheets were investigated systematically for the first time. Angle-resolved polarized Raman spectroscopy (ARPRS) shows distinct dependence on the excitation laser wavelength and sample thickness, demonstrating the robust wavelength-dependent optical absorption, electron-photon/electron-phonon interactions, and anisotropic phonon polarization in m-MoO2 nanosheets. Such results agree well with the semiclassical Placzek model. Moreover, the angle-dependent electrical conductivity of starburst-like m-MoO2 nanosheet devices shows a strong anisotropy with a conductivity ratio (σmax/σmin) of up to 10.1, which is the largest value in the previously reported 2D materials. This work underscores the importance of understanding the in-plane anisotropic light-matter interactions for the application of m-MoO2 nanosheets in anisotropic plasmonics and artificial synapse.
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Affiliation(s)
- Qi Zheng
- Synergetic Innovation Center for Quantum Effects and Application, Key Laboratory of Low-dimensional Quantum Structures and Quantum Control of Ministry of Education, School of Physics and Electronics , Hunan Normal University , Changsha 410081 , People's Republic of China
| | - Pinyun Ren
- Institute of Physics and Electronic Engineering , Sichuan University of Science and Engineering , Zigong 643000 , People's Republic of China
| | - Yuehua Peng
- Synergetic Innovation Center for Quantum Effects and Application, Key Laboratory of Low-dimensional Quantum Structures and Quantum Control of Ministry of Education, School of Physics and Electronics , Hunan Normal University , Changsha 410081 , People's Republic of China
| | - Weichang Zhou
- Synergetic Innovation Center for Quantum Effects and Application, Key Laboratory of Low-dimensional Quantum Structures and Quantum Control of Ministry of Education, School of Physics and Electronics , Hunan Normal University , Changsha 410081 , People's Republic of China
| | - Yanling Yin
- Synergetic Innovation Center for Quantum Effects and Application, Key Laboratory of Low-dimensional Quantum Structures and Quantum Control of Ministry of Education, School of Physics and Electronics , Hunan Normal University , Changsha 410081 , People's Republic of China
| | - Hao Wu
- Synergetic Innovation Center for Quantum Effects and Application, Key Laboratory of Low-dimensional Quantum Structures and Quantum Control of Ministry of Education, School of Physics and Electronics , Hunan Normal University , Changsha 410081 , People's Republic of China
| | - Wentao Gong
- Synergetic Innovation Center for Quantum Effects and Application, Key Laboratory of Low-dimensional Quantum Structures and Quantum Control of Ministry of Education, School of Physics and Electronics , Hunan Normal University , Changsha 410081 , People's Republic of China
| | - Weike Wang
- Synergetic Innovation Center for Quantum Effects and Application, Key Laboratory of Low-dimensional Quantum Structures and Quantum Control of Ministry of Education, School of Physics and Electronics , Hunan Normal University , Changsha 410081 , People's Republic of China
| | - Dongsheng Tang
- Synergetic Innovation Center for Quantum Effects and Application, Key Laboratory of Low-dimensional Quantum Structures and Quantum Control of Ministry of Education, School of Physics and Electronics , Hunan Normal University , Changsha 410081 , People's Republic of China
| | - Bingsuo Zou
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, School of Physics , Beijing Institute of Technology , Beijing 100081 , People's Republic of China
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17
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Xu X, Chen S, Liu S, Cheng X, Xu W, Li P, Wan Y, Yang S, Gong W, Yuan K, Gao P, Ye Y, Dai L. Millimeter-Scale Single-Crystalline Semiconducting MoTe 2 via Solid-to-Solid Phase Transformation. J Am Chem Soc 2019; 141:2128-2134. [PMID: 30633514 DOI: 10.1021/jacs.8b12230] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Among the Mo- and W-based two-dimensional (2D) transition metal dichalcogenides, MoTe2 is particularly interesting for phase-engineering applications, because it has the smallest free energy difference between the semiconducting 2H phase and metallic 1T' phase. In this work, we reveal that, under the proper circumstance, Mo and Te atoms can rearrange themselves to transform from a polycrystalline 1T' phase into a single-crystalline 2H phase in a large scale. We manifest the mechanisms of the solid-to-solid transformation by conducting density functional theory calculations, transmission electron microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy. The phase transformation is well described by the time-temperature-transformation diagram. By optimizing the kinetic rates of nucleation and crystal growth, we have synthesized a single-crystalline 2H-MoTe2 domain with a diameter of 2.34 mm, a centimeter-scale 2H-MoTe2 thin film with a domain size up to several hundred micrometers, and a seamless 1T'-2H MoTe2 coplanar homojunction. The 1T'-2H MoTe2 homojunction provides an elegant solution for ohmic contact of 2D semiconductors. The controlled solid-to-solid phase transformation in 2D limit provides a new route to realize wafer-scale single-crystalline 2D semiconductor and coplanar heterostructure for 2D circuitry.
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Affiliation(s)
- Xiaolong Xu
- State Key Lab for Artificial Microstructure & Mesoscopic Physics, School of Physics , Peking University , Beijing 100871 , China.,Collaborative Innovation Center of Quantum Matter , Beijing 100871 , China
| | - Shulin Chen
- Electron Microscopy Laboratory, School of Physics , Peking University , Beijing 100871 , China
| | - Shuai Liu
- State Key Lab for Artificial Microstructure & Mesoscopic Physics, School of Physics , Peking University , Beijing 100871 , China
| | - Xing Cheng
- State Key Lab for Artificial Microstructure & Mesoscopic Physics, School of Physics , Peking University , Beijing 100871 , China
| | - Wanjin Xu
- State Key Lab for Artificial Microstructure & Mesoscopic Physics, School of Physics , Peking University , Beijing 100871 , China
| | - Pan Li
- State Key Lab for Artificial Microstructure & Mesoscopic Physics, School of Physics , Peking University , Beijing 100871 , China
| | - Yi Wan
- State Key Lab for Artificial Microstructure & Mesoscopic Physics, School of Physics , Peking University , Beijing 100871 , China
| | - Shiqi Yang
- State Key Lab for Artificial Microstructure & Mesoscopic Physics, School of Physics , Peking University , Beijing 100871 , China.,Academy for Advanced Interdisciplinary Studies , Peking University , Beijing 100871 , China
| | - Wenting Gong
- State Key Lab for Artificial Microstructure & Mesoscopic Physics, School of Physics , Peking University , Beijing 100871 , China
| | - Kai Yuan
- State Key Lab for Artificial Microstructure & Mesoscopic Physics, School of Physics , Peking University , Beijing 100871 , China
| | - Peng Gao
- Collaborative Innovation Center of Quantum Matter , Beijing 100871 , China.,Electron Microscopy Laboratory, School of Physics , Peking University , Beijing 100871 , China.,International Center for Quantum Materials, School of Physics , Peking University , Beijing 100871 , China
| | - Yu Ye
- State Key Lab for Artificial Microstructure & Mesoscopic Physics, School of Physics , Peking University , Beijing 100871 , China.,Collaborative Innovation Center of Quantum Matter , Beijing 100871 , China
| | - Lun Dai
- State Key Lab for Artificial Microstructure & Mesoscopic Physics, School of Physics , Peking University , Beijing 100871 , China.,Collaborative Innovation Center of Quantum Matter , Beijing 100871 , China
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18
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Hoang AT, Shinde SM, Katiyar AK, Dhakal KP, Chen X, Kim H, Lee SW, Lee Z, Ahn JH. Orientation-dependent optical characterization of atomically thin transition metal ditellurides. NANOSCALE 2018; 10:21978-21984. [PMID: 30451270 DOI: 10.1039/c8nr07592a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Molybdenum ditellurides (MoTe2) have recently attracted attention owing to their excellent structurally tunable nature between 1T'(metallic)- and 2H(semiconducting)-phases; thus, the controllable fabrication and critical identification of MoTe2 are highly desired. Here, we semi-controllably synthesized 1T'- and 2H-MoTe2 crystals using the atmospheric pressure chemical vapor deposition (APCVD) technique and studied their grain-orientation dependency using polarization-sensitive optical microscopy, Raman scattering, and second-harmonic generation (SHG) microspectroscopy. The polycrystalline 1T'-MoTe2 phase with quasi-1D "Mo-Mo" zigzag chains showed anisotropic optical absorption, leading to a clear visualization of the lattice domains. On the other hand, 2H-MoTe2 lattice grains did not exhibit any discernible difference under polarized light illumination. The combined aforementioned microscopy techniques could be used as an easy-to-access and non-destructive tool for a quick and solid identification of intended lattice orientation development in industry-scale MoTe2 crystal manufacturing.
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Affiliation(s)
- Anh Tuan Hoang
- School of Electrical and Electronic Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea.
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19
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Wu J, Xie L. Structural Quantification for Graphene and Related Two-Dimensional Materials by Raman Spectroscopy. Anal Chem 2018; 91:468-481. [DOI: 10.1021/acs.analchem.8b04991] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Juanxia Wu
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, P. R. China
| | - Liming Xie
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, P. R. China
- School of Nanoscience and Technology, University of Chinese Academy of Sciences, Beijing 100049, P. R. China
- International College, University of Chinese Academy of Sciences, Beijing 100049, P. R. China
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20
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Kang S, Jeon S, Kim S, Seol D, Yang H, Lee J, Kim Y. Tunable Out-of-Plane Piezoelectricity in Thin-Layered MoTe 2 by Surface Corrugation-Mediated Flexoelectricity. ACS APPLIED MATERIALS & INTERFACES 2018; 10:27424-27431. [PMID: 30022658 DOI: 10.1021/acsami.8b06325] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Piezoelectricity crystallographically exists only in the in-plane direction in two-dimensional transition metal dichalcogenides. Here, we demonstrated flexoelectricity-tunable out-of-plane piezoelectricity in semiconducting 2H-MoTe2 flakes by creating surface corrugation. In particular, the strong out-of-plane piezoelectricity and its spatial variation depending on local flexoelectricity was observed even though crystallographically there exists only in-plane piezoelectricity. Surface corrugation-mediated flexoelectricity tuning can be applied to other two-dimensional or thin-layered materials and, furthermore, the results could provide useful information on the interweaving nature between mechanical stimulus and electric dipole in low-dimensional materials.
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Affiliation(s)
| | - Sera Jeon
- Department of Physics , Pusan National University , Busan 46241 , Republic of Korea
| | | | | | | | - Jaekwang Lee
- Department of Physics , Pusan National University , Busan 46241 , Republic of Korea
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Structural phase transition in monolayer MoTe2 driven by electrostatic doping. Nature 2017; 550:487-491. [DOI: 10.1038/nature24043] [Citation(s) in RCA: 428] [Impact Index Per Article: 61.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 08/10/2017] [Indexed: 12/22/2022]
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