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Bhatt K, Kandar S, Kumar N, Kapoor A, Singh R. Effective concentration ratio driven phase engineering of MBE-grown few-layer MoTe 2. NANOSCALE 2024; 16:15381-15395. [PMID: 39092858 DOI: 10.1039/d4nr00687a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/04/2024]
Abstract
The polymorphic nature of ultrathin transition metal dichalcogenide (TMDC) materials makes the phase engineering of these materials an interesting field of investigation. Understanding the phase-controlling behavior of different growth parameters is crucial for obtaining large-area growth of a desirable phase. Here, we report a detailed study on the effect of growth parameters for engineering different phases of few-layer MoTe2 on sapphire using molecular beam epitaxy (MBE). Our study shows that the 2H phase of MoTe2 is stabilized in a certain regime of the flux ratio and growth temperature, while on both the lower, as well as, the higher sides of this regime, the 1T' phase is favored. The combined effect of growth parameters is explained using the effective concentration ratio of Te and Mo at the growth surface, which is found to be the primary factor governing the phase selectivity in few-layer MoTe2. XPS and KPFM investigations show the contribution of excess carrier doping in driving the phase change. The effect of the sapphire substrate on the crystallinity and phase-dependent morphological features has also been studied. This knowledge of versatile and controlled phase engineering of few-layer MoTe2 paves the way for fabricating large-scale hetero-phase-based metal-semiconductor heterostructures for future electronic and optoelectronic device applications.
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Affiliation(s)
- Kamlesh Bhatt
- Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
| | - Santanu Kandar
- Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
| | - Nand Kumar
- School of Interdisciplinary Research (SIRe), Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Ashok Kapoor
- Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
| | - Rajendra Singh
- Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
- School of Interdisciplinary Research (SIRe), Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
- Department of Electrical Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
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2
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Chen J, Huang J, Zheng T, Yang M, Chen S, Ma J, Jian L, Pan Y, Zheng Z, Huo N, Gao W, Li J. 2D Reconfigurable van der Waals Heterojunction for Logic Gate Circuits and Wide-Spectrum Photodetectors via Sulfur Substitution and Band Matching. ACS APPLIED MATERIALS & INTERFACES 2024; 16:38231-38242. [PMID: 39001805 DOI: 10.1021/acsami.4c06028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/15/2024]
Abstract
The attractive physical properties of two-dimensional (2D) semiconductors in group IVA-VIA have been fully revealed in recent years. Combining them with 2D ambipolar materials to construct van der Waals heterojunctions (vdWHs) can offer tremendous opportunities for designing multifunctional electronic and optoelectronic devices, such as logic switching circuits, half-wave rectifiers, and broad-spectrum photodetectors. Here, an optimized SnSe0.75S0.25 is grown to design a SnSe0.75S0.25/MoTe2 vdWH for logic operation and wide-spectrum photodetection. Benefiting from the excellent gate modulation under the appropriate sulfur substitution and type-II band alignment, the device exhibits reconfigurable antiambipolar and ambipolar transfer behaviors at positive and negative source-drain voltage (Vds), enabling stable XNOR logic operation. It also features a gate-modulated positive and negative rectifying behavior with rectification ratios of 265:1 and 1:196, confirming its potential as half-wave logic rectifiers. Besides, the device can respond from visible to infrared wavelength up to 1400 nm. Under 635 nm illumination, the maximum responsivity of 1.16 A/W and response time of 657/500 μs are achieved at the Vds of -2 V. Furthermore, due to the strong in-plane anisotropic structure of SnSe0.75S0.25-alloyed nanosheet and narrow bandgap of 2H-MoTe2, it shows a broadband polarization-sensitive function with impressive photocurrent anisotropic ratios of 15.6 (635 nm), 7.0 (808 nm), and 3.7 (1310 nm). The direction along the maximum photocurrent can be reconfigurable depending on the wavelengths. These results indicate that our designed alloyed SnSe0.75S0.25/MoTe2 vdWH has reconfigurable logic operation and broadband photodetection capabilities in 2D multifunctional integrated circuits.
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Affiliation(s)
- Jianru Chen
- Guangdong Provincial Key Laboratory of Chip and Integration Technology, School of Semiconductor Science and Technology, Faculty of Engineering, South China Normal University, Foshan 528225, P. R. China
| | - Jianming Huang
- Guangdong Provincial Key Laboratory of Chip and Integration Technology, School of Semiconductor Science and Technology, Faculty of Engineering, South China Normal University, Foshan 528225, P. R. China
| | - Tao Zheng
- Guangdong Provincial Key Laboratory of Chip and Integration Technology, School of Semiconductor Science and Technology, Faculty of Engineering, South China Normal University, Foshan 528225, P. R. China
| | - Mengmeng Yang
- Guangdong Provincial Key Laboratory of Chip and Integration Technology, School of Semiconductor Science and Technology, Faculty of Engineering, South China Normal University, Foshan 528225, P. R. China
| | - Shengdi Chen
- Guangdong Provincial Key Laboratory of Chip and Integration Technology, School of Semiconductor Science and Technology, Faculty of Engineering, South China Normal University, Foshan 528225, P. R. China
| | - Jingyi Ma
- Guangdong Provincial Key Laboratory of Chip and Integration Technology, School of Semiconductor Science and Technology, Faculty of Engineering, South China Normal University, Foshan 528225, P. R. China
| | - Liang Jian
- Guangdong Provincial Key Laboratory of Chip and Integration Technology, School of Semiconductor Science and Technology, Faculty of Engineering, South China Normal University, Foshan 528225, P. R. China
| | - Yuan Pan
- Guangdong Provincial Key Laboratory of Chip and Integration Technology, School of Semiconductor Science and Technology, Faculty of Engineering, South China Normal University, Foshan 528225, P. R. China
| | - Zhaoqiang Zheng
- School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, P. R. China
| | - Nengjie Huo
- Guangdong Provincial Key Laboratory of Chip and Integration Technology, School of Semiconductor Science and Technology, Faculty of Engineering, South China Normal University, Foshan 528225, P. R. China
| | - Wei Gao
- Guangdong Provincial Key Laboratory of Chip and Integration Technology, School of Semiconductor Science and Technology, Faculty of Engineering, South China Normal University, Foshan 528225, P. R. China
| | - Jingbo Li
- College of Optical Science and Engineering, Zhejiang University, Hangzhou 310027, P. R. China
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3
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Chen L, Chen L, Chen H, Jiang K, Zhu L, Shang L, Li Y, Gong S, Hu Z. Phase transition in WSe 2-xTe x monolayers driven by charge injection and pressure: a first-principles study. NANOSCALE 2024. [PMID: 38477210 DOI: 10.1039/d3nr06164g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/14/2024]
Abstract
Alloying strategies permit new probes for governing structural stability and semiconductor-semimetal phase transition of transition metal dichalcogenides (TMDs). However, the possible structure and phase transition mechanism of the alloy TMDs, and the effect of an external field, have been still unclear. Here, the enrichment of the Te content in WSe2-xTex monolayers allows for coherent structural transition from the H phase to the T' phase. The crystal orbital Hamiltonian population (COHP) uncovers that the bonding state of the H phase approaches the high-energy domain near the Fermi level as the Te concentration increases, posing a source of structural instability followed by a weakened energy barrier for the phase transition. In addition, the structural phase transition driven by charge injection opens up new possibilities for the development of phase-change devices based on atomic thin films. For WSe2-xTex monolayers with the H phase as the stable phase, the critical value of electron concentration triggering the phase transition decreases with an increase in the x value. Furthermore, the energy barrier from the H phase to the T' phase can be effectively reduced by applying tensile strain, which could favor the phase switching in electronic devices. This work provides a critical reference for controllable modulation of phase-sensitive devices from alloy materials with rich phase characteristics.
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Affiliation(s)
- Liyuan Chen
- Technical Center for Multifunctional Magneto-Optical Spectroscopy (Shanghai), Engineering Research Center of Nanophotonics & Advanced Instrument (Ministry of Education), Department of Physics, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China.
| | - Li Chen
- Technical Center for Multifunctional Magneto-Optical Spectroscopy (Shanghai), Engineering Research Center of Nanophotonics & Advanced Instrument (Ministry of Education), Department of Physics, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China.
| | - Hongli Chen
- Technical Center for Multifunctional Magneto-Optical Spectroscopy (Shanghai), Engineering Research Center of Nanophotonics & Advanced Instrument (Ministry of Education), Department of Physics, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China.
| | - Kai Jiang
- Technical Center for Multifunctional Magneto-Optical Spectroscopy (Shanghai), Engineering Research Center of Nanophotonics & Advanced Instrument (Ministry of Education), Department of Physics, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China.
| | - Liangqing Zhu
- Technical Center for Multifunctional Magneto-Optical Spectroscopy (Shanghai), Engineering Research Center of Nanophotonics & Advanced Instrument (Ministry of Education), Department of Physics, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China.
| | - Liyan Shang
- Technical Center for Multifunctional Magneto-Optical Spectroscopy (Shanghai), Engineering Research Center of Nanophotonics & Advanced Instrument (Ministry of Education), Department of Physics, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China.
| | - Yawei Li
- Technical Center for Multifunctional Magneto-Optical Spectroscopy (Shanghai), Engineering Research Center of Nanophotonics & Advanced Instrument (Ministry of Education), Department of Physics, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China.
| | - Shijing Gong
- Technical Center for Multifunctional Magneto-Optical Spectroscopy (Shanghai), Engineering Research Center of Nanophotonics & Advanced Instrument (Ministry of Education), Department of Physics, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China.
| | - Zhigao Hu
- Technical Center for Multifunctional Magneto-Optical Spectroscopy (Shanghai), Engineering Research Center of Nanophotonics & Advanced Instrument (Ministry of Education), Department of Physics, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China.
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
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4
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Martín Sabanés N, Eaton MD, Moreno-Da Silva S, Naranjo A, Pérez EM. Automated statistical analysis of raman spectra of nanomaterials. NANOSCALE 2024; 16:2048-2059. [PMID: 38204411 DOI: 10.1039/d3nr03602b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
Both at the academic and the industrial level, material scientists are exploring routes for mass production and functionalization of graphene, carbon nanotubes (CNT), carbon dots, 2D materials, and heterostructures of these. Proper application of the novel materials requires fast and thorough characterization of the samples. Raman spectroscopy stands out as a standard non-invasive technique capable of giving key information on the structure and electronic properties of nanomaterials, including the presence of defects, degree of functionalization, diameter (in the case of CNT), different polytypes, doping, etc. Here, we present a computational tool to automatically analyze the Raman spectral features of nanomaterials, which we illustrate with the example of CNT and graphene. The algorithm manages hundreds of spectra simultaneously and provides statistical information (distribution of Raman shifts, average values of shifts and relative intensities, standard deviations, correlation between different peaks, etc.) of the main spectral features defining the structure and electronic properties of the samples, as well as publication-ready graphical material.
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5
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Reuter C, Ecke G, Strehle S. Exploring the Surface Oxidation and Environmental Instability of 2H-/1T'-MoTe 2 Using Field Emission-Based Scanning Probe Lithography. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2310887. [PMID: 37931614 DOI: 10.1002/adma.202310887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Indexed: 11/08/2023]
Abstract
An unconventional approach for the resistless nanopatterning 2H- and 1T'-MoTe2 by means of scanning probe lithography is presented. A Fowler-Nordheim tunneling current of low energetic electrons (E = 30-60 eV) emitted from the tip of an atomic force microscopy (AFM) cantilever is utilized to induce a nanoscale oxidation on a MoTe2 nanosheet surface under ambient conditions. Due to the water solubility of the generated oxide, a direct pattern transfer into the MoTe2 surface can be achieved by a simple immersion of the sample in deionized water. The tip-grown oxide is characterized using Auger electron and Raman spectroscopy, revealing it consists of amorphous MoO3 /MoOx as well as TeO2 /TeOx . With the presented technology in combination with subsequent AFM imaging it is possible to demonstrate a strong anisotropic sensitivity of 1T'-/(Td )-MoTe2 to aqueous environments. Finally the discussed approach is used to structure a nanoribbon field effect transistor out of a few-layer 2H-MoTe2 nanosheet.
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Affiliation(s)
- Christoph Reuter
- Institute of Micro- and Nanotechnologies, Microsystems Technology Group, Technische Universität Ilmenau, Max-Planck-Ring 12, 98693, Ilmenau, Germany
| | - Gernot Ecke
- Institute of Micro- and Nanotechnologies, Nanotechnology Group, Technische Universität Ilmenau, Gustav-Kirchhoff-Straße 1, 98693, Ilmenau, Germany
| | - Steffen Strehle
- Institute of Micro- and Nanotechnologies, Microsystems Technology Group, Technische Universität Ilmenau, Max-Planck-Ring 12, 98693, Ilmenau, Germany
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6
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Yin Z, Panaccione W, Hu A, Douglas ORT, Tanjil MRE, Jeong Y, Zhao H, Wang MC. Directionally-Resolved Phononic Properties of Monolayer 2D Molybdenum Ditelluride (MoTe 2) under Uniaxial Elastic Strain. NANO LETTERS 2023; 23:11763-11770. [PMID: 38100381 DOI: 10.1021/acs.nanolett.3c03706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2023]
Abstract
Understanding the phonon characteristics of two-dimensional (2D) molybdenum ditelluride (MoTe2) under strain is critical to manipulating its multiphysical properties. Although there have been numerous computational efforts to elucidate the strain-coupled phonon properties of monolayer MoTe2, empirical validation is still lacking. In this work, monolayer 1H-MoTe2 under uniaxial strain is studied via in situ micro-Raman spectroscopy. Directionally dependent monotonic softening of the doubly degenerate in-plane E2g1 phonon mode is observed with increasing uniaxial strain, where the E2g1 peak red-shifts -1.66 ± 0.04 cm-1/% along the armchair direction and -0.80 ± 0.07 cm-1/% along the zigzag direction. The corresponding Grüneisen parameters are calculated to be 1.09 and 0.52 along the armchair and zigzag directions, respectively. This work provides the first empirical quantification and validation of the orientation-dependent strain-coupled phonon response in monolayer 1H-MoTe2 and serves as a benchmark for other prototypical 2D transition-metal tellurides.
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Affiliation(s)
- Zhewen Yin
- Department of Mechanical Engineering, University of South Florida, Tampa, Florida 33620, United States
| | - Wyatt Panaccione
- Department of Mechanical Engineering, University of South Florida, Tampa, Florida 33620, United States
| | - Anjun Hu
- Department of Medical Engineering, University of South Florida, Tampa, Florida 33620, United States
| | - Ossie R T Douglas
- Department of Mechanical Engineering, University of South Florida, Tampa, Florida 33620, United States
| | - Md Rubayat-E Tanjil
- Department of Mechanical Engineering, University of South Florida, Tampa, Florida 33620, United States
| | - Yunjo Jeong
- Department of Mechanical Engineering, University of South Florida, Tampa, Florida 33620, United States
| | - Huijuan Zhao
- Department of Mechanical Engineering, Clemson University, Clemson, South Carolina 29634-0921, United States
| | - Michael Cai Wang
- Department of Mechanical Engineering, University of South Florida, Tampa, Florida 33620, United States
- Department of Medical Engineering, University of South Florida, Tampa, Florida 33620, United States
- Department of Chemical, Biological, and Materials Engineering, University of South Florida, Tampa, Florida 33620, United States
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7
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Liu F, Lin X, Yan Y, Gan X, Cheng Y, Luo X. Self-Powered Programmable van der Waals Photodetectors with Nonvolatile Semifloating Gate. NANO LETTERS 2023; 23:11645-11654. [PMID: 38088857 DOI: 10.1021/acs.nanolett.3c03500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2023]
Abstract
Tunable photovoltaic photodetectors are of significant relevance in the fields of programmable and neuromorphic optoelectronics. However, their widespread adoption is hindered by intricate architectural design and energy consumption challenges. This study employs a nonvolatile MoTe2/hexagonal boron nitride/graphene semifloating photodetector to address these issues. Programed with pulsed gate voltage, the MoTe2 channel can be reconfigured from an n+-n to a p-n homojunction and the photocurrent transition changes from negative to positive values. Scanning photocurrent mapping reveals that the negative and positive photocurrents are attributed to Schottky junction and p-n homojunction, respectively. In the p-n configuration, the device demonstrates self-driven, linear, rapid response (∼3 ms), and broadband sensitivity (from 405 to 1500 nm) for photodetection, with typical performances of responsivity at ∼0.5 A/W and detectivity ∼1.6 × 1012 Jones under 635 nm illumination. These outstanding photodetection capabilities emphasize the potential of the semifloating photodetector as a pioneering approach for advancing logical and nonvolatile optoelectronics.
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Affiliation(s)
- Fan Liu
- Frontiers Science Center for Flexible Electronics (FSCFE), Shaanxi Institute of Flexible Electronics (SIFE) & Shaanxi Institute of Biomedical Materials and Engineering (SIBME), Northwestern Polytechnical University, Xi'an 710129, China
| | - Xi Lin
- Frontiers Science Center for Flexible Electronics (FSCFE), Shaanxi Institute of Flexible Electronics (SIFE) & Shaanxi Institute of Biomedical Materials and Engineering (SIBME), Northwestern Polytechnical University, Xi'an 710129, China
| | - Yuting Yan
- Frontiers Science Center for Flexible Electronics (FSCFE), Shaanxi Institute of Flexible Electronics (SIFE) & Shaanxi Institute of Biomedical Materials and Engineering (SIBME), Northwestern Polytechnical University, Xi'an 710129, China
| | - Xuetao Gan
- Key Laboratory of Light Field Manipulation and Information Acquisition, Ministry of Industry and Information Technology, and Shaanxi Key Laboratory of Optical Information Technology, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710129, China
| | - Yingchun Cheng
- Key Laboratory of Flexible Electronics & Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, Nanjing 211816, China
| | - Xiaoguang Luo
- Frontiers Science Center for Flexible Electronics (FSCFE), Shaanxi Institute of Flexible Electronics (SIFE) & Shaanxi Institute of Biomedical Materials and Engineering (SIBME), Northwestern Polytechnical University, Xi'an 710129, China
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8
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Lee D, Jeong H, Lee H, Kim YH, Park JY. Phase-dependent Friction on Exfoliated Transition Metal Dichalcogenides Atomic Layers. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2302713. [PMID: 37485739 DOI: 10.1002/smll.202302713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 07/07/2023] [Indexed: 07/25/2023]
Abstract
The fundamental aspects of energy dissipation on 2-dimensional (2D) atomic layers are extensively studied. Among various atomic layers, transition metal dichalcogenides (TMDs) exists in several phases based on their lattice structure, which give rise to the different phononic and electronic contributions in energy dissipation. 2H and 1T' (distorted 1T) phase MoS2 and MoTe2 atomic layers exfoliated on mica substrate are obtained and investigated their nanotribological properties with atomic force microscopy (AFM)/ friction force microscopy (FFM). Surprisingly, 1T' phase of both MoS2 and MoTe2 exhibits ≈10 times higher friction compared to 2H phase. With density functional theory analyses, the friction increase is attributed to enhanced electronic excitation, efficient phonon dissipation, and increased potential energy surface barrier at the tip-sample interface. This study suggests the intriguing possibility of tuning the friction of TMDs through phase transition, which can lead to potential application in tunable tribological devices.
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Affiliation(s)
- Dooho Lee
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Hochan Jeong
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Hyunsoo Lee
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Yong-Hyun Kim
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
- Graduate School of Nanoscience and Technology, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Jeong Young Park
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
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9
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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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Shi J, Bie YQ, Zong A, Fang S, Chen W, Han J, Cao Z, Zhang Y, Taniguchi T, Watanabe K, Fu X, Bulović V, Kaxiras E, Baldini E, Jarillo-Herrero P, Nelson KA. Intrinsic 1[Formula: see text] phase induced in atomically thin 2H-MoTe 2 by a single terahertz pulse. Nat Commun 2023; 14:5905. [PMID: 37737233 PMCID: PMC10516973 DOI: 10.1038/s41467-023-41291-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Accepted: 08/29/2023] [Indexed: 09/23/2023] Open
Abstract
The polymorphic transition from 2H to 1[Formula: see text]-MoTe2, which was thought to be induced by high-energy photon irradiation among many other means, has been intensely studied for its technological relevance in nanoscale transistors due to the remarkable improvement in electrical performance. However, it remains controversial whether a crystalline 1[Formula: see text] phase is produced because optical signatures of this putative transition are found to be associated with the formation of tellurium clusters instead. Here we demonstrate the creation of an intrinsic 1[Formula: see text] lattice after irradiating a mono- or few-layer 2H-MoTe2 with a single field-enhanced terahertz pulse. Unlike optical pulses, the low terahertz photon energy limits possible structural damages. We further develop a single-shot terahertz-pump-second-harmonic-probe technique and reveal a transition out of the 2H-phase within 10 ns after photoexcitation. Our results not only provide important insights to resolve the long-standing debate over the light-induced polymorphic transition in MoTe2 but also highlight the unique capability of strong-field terahertz pulses in manipulating quantum materials.
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Affiliation(s)
- Jiaojian Shi
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139 USA
| | - Ya-Qing Bie
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 USA
- State Key Lab of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou, 510275 People’s Republic of China
| | - Alfred Zong
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 USA
- Department of Chemistry, University of California, Berkeley, CA 94720 USA
| | - Shiang Fang
- Department of Physics, Harvard University, Cambridge, MA 02138 USA
- Department of Physics and Astronomy, Center for Materials Theory, Rutgers University, Piscataway, NJ 08854 USA
- Present Address: Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 USA
| | - Wei Chen
- Department of Physics, Harvard University, Cambridge, MA 02138 USA
| | - Jinchi Han
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139 USA
- School of Integrated Circuits, Peking University, Beijing, 100871 People’s Republic of China
| | - Zhaolong Cao
- State Key Lab of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou, 510275 People’s Republic of China
| | - Yong Zhang
- Center for Materials Science & Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 USA
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044 Japan
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044 Japan
| | - Xuewen Fu
- Ultrafast Electron Microscopy Laboratory, The MOE Key Laboratory of Weak-Light Nonlinear Photonics, School of Physics, Nankai University, Tianjin, 300071 People’s Republic of China
| | - Vladimir Bulović
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139 USA
| | | | - Edoardo Baldini
- Department of Physics, Center for Complex Quantum System, The University of Texas at Austin, Austin, TX 78712 USA
| | - Pablo Jarillo-Herrero
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 USA
| | - Keith A. Nelson
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139 USA
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11
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Jang YJ, Paul KK, Park JC, Kim M, Tran MD, Song HY, Yun SJ, Lee H, Enkhbat T, Kim J, Lee YH, Kim JH. Boosting internal quantum efficiency via ultrafast triplet transfer to 2H-MoTe 2 film. SCIENCE ADVANCES 2023; 9:eadg2324. [PMID: 37343104 DOI: 10.1126/sciadv.adg2324] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 05/16/2023] [Indexed: 06/23/2023]
Abstract
Organic systems often allow to create two triplet spin states (triplet excitons) by converting an initially excited singlet spin state (a singlet exciton). An ideally designed organic/inorganic heterostructure could reach the photovoltaic energy harvest over the Shockley-Queisser (S-Q) limit because of the efficient conversion of triplet excitons into charge carriers. Here, we demonstrate the molybdenum ditelluride (MoTe2)/pentacene heterostructure to boost the carrier density via efficient triplet transfer from pentacene to MoTe2 using ultrafast transient absorption spectroscopy. We observe carrier multiplication by nearly four times by doubling carriers in MoTe2 via the inverse Auger process and subsequently doubling carriers via triplet extraction from pentacene. We also verify efficient energy conversion by doubling the photocurrent in the MoTe2/pentacene film. This puts a step forward to enhancing photovoltaic conversion efficiency beyond the S-Q limit in the organic/inorganic heterostructures.
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Affiliation(s)
- Yu Jin Jang
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
- Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Kamal Kumar Paul
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
- Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Jin Cheol Park
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Meeree Kim
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
- Department of Chemistry, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Minh Dao Tran
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
- Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Hyun Yong Song
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Seok Joon Yun
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
- Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Hyoyoung Lee
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
- Department of Chemistry, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Temujin Enkhbat
- Department of Physics, Incheon National University, Incheon 22012, Republic of Korea
| | - JunHo Kim
- Department of Physics, Incheon National University, Incheon 22012, Republic of Korea
| | - Young Hee Lee
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Ji-Hee Kim
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
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12
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Jones LH, Xing Z, Swallow JEN, Shiel H, Featherstone TJ, Smiles MJ, Fleck N, Thakur PK, Lee TL, Hardwick LJ, Scanlon DO, Regoutz A, Veal TD, Dhanak VR. Band Alignments, Electronic Structure, and Core-Level Spectra of Bulk Molybdenum Dichalcogenides (MoS 2, MoSe 2, and MoTe 2). THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2022; 126:21022-21033. [PMID: 36561200 PMCID: PMC9761681 DOI: 10.1021/acs.jpcc.2c05100] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 11/12/2022] [Indexed: 06/17/2023]
Abstract
A comprehensive study of bulk molybdenum dichalcogenides is presented with the use of soft and hard X-ray photoelectron (SXPS and HAXPES) spectroscopy combined with hybrid density functional theory (DFT). The main core levels of MoS2, MoSe2, and MoTe2 are explored. Laboratory-based X-ray photoelectron spectroscopy (XPS) is used to determine the ionization potential (IP) values of the MoX2 series as 5.86, 5.40, and 5.00 eV for MoSe2, MoSe2, and MoTe2, respectively, enabling the band alignment of the series to be established. Finally, the valence band measurements are compared with the calculated density of states which shows the role of p-d hybridization in these materials. Down the group, an increase in the p-d hybridization from the sulfide to the telluride is observed, explained by the configuration energy of the chalcogen p orbitals becoming closer to that of the valence Mo 4d orbitals. This pushes the valence band maximum closer to the vacuum level, explaining the decreasing IP down the series. High-resolution SXPS and HAXPES core-level spectra address the shortcomings of the XPS analysis in the literature. Furthermore, the experimentally determined band alignment can be used to inform future device work.
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Affiliation(s)
- Leanne
A. H. Jones
- Stephenson
Institute for Renewable Energy and Department of Physics, University of Liverpool, LiverpoolL69 7ZF, U.K.
| | - Zongda Xing
- Department
of Chemistry, University College London, 20 Gordon Street, LondonWC1H 0AJ, U.K.
| | - Jack E. N. Swallow
- Stephenson
Institute for Renewable Energy and Department of Physics, University of Liverpool, LiverpoolL69 7ZF, U.K.
| | - Huw Shiel
- Stephenson
Institute for Renewable Energy and Department of Physics, University of Liverpool, LiverpoolL69 7ZF, U.K.
| | - Thomas J. Featherstone
- Stephenson
Institute for Renewable Energy and Department of Physics, University of Liverpool, LiverpoolL69 7ZF, U.K.
| | - Matthew J. Smiles
- Stephenson
Institute for Renewable Energy and Department of Physics, University of Liverpool, LiverpoolL69 7ZF, U.K.
| | - Nicole Fleck
- Stephenson
Institute for Renewable Energy and Department of Physics, University of Liverpool, LiverpoolL69 7ZF, U.K.
| | - Pardeep K. Thakur
- Diamond
Light Source Ltd., Diamond House, Harwell
Science and Innovation Campus, Didcot, OxfordshireOX11 0DE, U.K.
| | - Tien-Lin Lee
- Diamond
Light Source Ltd., Diamond House, Harwell
Science and Innovation Campus, Didcot, OxfordshireOX11 0DE, U.K.
| | - Laurence J. Hardwick
- Stephenson
Institute for Renewable Energy and Department of Chemistry, University of Liverpool, LiverpoolL69 7ZF, U.K.
| | - David O. Scanlon
- Department
of Chemistry, University College London, 20 Gordon Street, LondonWC1H 0AJ, U.K.
| | - Anna Regoutz
- Department
of Chemistry, University College London, 20 Gordon Street, LondonWC1H 0AJ, U.K.
| | - Tim D. Veal
- Stephenson
Institute for Renewable Energy and Department of Physics, University of Liverpool, LiverpoolL69 7ZF, U.K.
| | - Vinod R. Dhanak
- Stephenson
Institute for Renewable Energy and Department of Physics, University of Liverpool, LiverpoolL69 7ZF, U.K.
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13
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Sagar P, Srivastava M, Tiwari RK, Kumar A, Srivastava A, Pandey G, Srivastava S. In-situ One-pot Novel Synthesis of Molybdenum di-Telluride@Carbon Nano-Dots for Sensitive and Selective Detection of Hydrogen Peroxide Molecules via Turn-off Fluorescence Mechanism. Microchem J 2022. [DOI: 10.1016/j.microc.2022.108134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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14
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Quantitative analysis of temperature-dependent vibrational properties of Cobalt incorporated WSe2 ternary alloy. J SOLID STATE CHEM 2022. [DOI: 10.1016/j.jssc.2022.123359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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15
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Ko BM, Khan MF, Dastgeer G, Han GN, Khan MA, Eom J. Reconfigurable carrier type and photodetection of MoTe 2 of various thicknesses by deep ultraviolet light illumination. NANOSCALE ADVANCES 2022; 4:2744-2751. [PMID: 36132280 PMCID: PMC9417606 DOI: 10.1039/d1na00881a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 05/09/2022] [Indexed: 06/15/2023]
Abstract
Tuning of the Fermi level in transition metal dichalcogenides (TMDCs) leads to devices with excellent electrical and optical properties. In this study, we controlled the Fermi level of MoTe2 by deep ultraviolet (DUV) light illumination in different gaseous environments. Specifically, we investigated the reconfigurable carrier type of an intrinsic p-MoTe2 flake that gradually transformed into n-MoTe2 after illumination with DUV light for 30, 60, 90, 120, 160, 250, 500, 900, and 1200 s in a nitrogen (N2) gas environment. Subsequently, we illuminated this n-MoTe2 sample with DUV light in oxygen (O2) gas and reversed its carrier polarity toward p-MoTe2. However, using this doping scheme to reveal the effect of DUV light on various layers (3-30 nm) of MoTe2 is challenging. The DUV + N2 treatment significantly altered the polarity of MoTe2 of different thicknesses from p-type to n-type under the DUV + N2 treatment, but the DUV + O2 treatment did not completely alter the polarity of thicker n-MoTe2 flakes to p-type. In addition, we investigated the photoresponse of MoTe2 after DUV light treatment in N2 and O2 gas environments. From the time-resolved photoresponsivity at different polarity states of MoTe2, we have shown that the response time of the DUV + O2 treated p-MoTe2 is faster than that of the pristine and doped n-MoTe2 films. These carrier polarity modulations and photoresponse paves the way for wider applications of MoTe2 in optoelectronic devices.
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Affiliation(s)
- Byung Min Ko
- Department of Physics & Astronomy and Graphene Research Institute, Sejong University Seoul 05006 Korea
| | - Muhammad Farooq Khan
- Department of Electrical Engineering, Sejong University 209 Neungdong-ro, Gwangjin-gu Seoul 05006 Korea
| | - Ghulam Dastgeer
- Department of Physics & Astronomy and Graphene Research Institute, Sejong University Seoul 05006 Korea
| | - Gyu Nam Han
- Department of Physics & Astronomy and Graphene Research Institute, Sejong University Seoul 05006 Korea
| | - Muhammad Asghar Khan
- Department of Physics & Astronomy and Graphene Research Institute, Sejong University Seoul 05006 Korea
| | - Jonghwa Eom
- Department of Physics & Astronomy and Graphene Research Institute, Sejong University Seoul 05006 Korea
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16
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Negedu SD, Tromer R, Gowda CC, Woellner CF, Olu FE, Roy AK, Pandey P, Galvao DS, Ajayan PM, Kumbhakar P, Tiwary CS. Two-dimensional cobalt telluride as a piezo-tribogenerator. NANOSCALE 2022; 14:7788-7797. [PMID: 35394476 DOI: 10.1039/d2nr00132b] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Two-dimensional (2D) materials have been shown to be efficient in energy harvesting. Here, we report the use of waste heat to generate electricity via the combined piezoelectric and triboelectric properties of 2D cobalt telluride (CoTe2). The piezo-triboelectric nanogenerator (PTNG) produced an open-circuit voltage of ∼5 V under 1 N force and the effect of temperature in the range of 305-363 K shows a four-fold energy conversion efficiency improvement. The 2D piezo-tribogenerator shows excellent characteristics with a maximum voltage of ∼10 V, fast response time, and high responsivity. Density functional theory was used to gain further insights and validation of the experimental results. Our results could lead to energy harvesting approaches using 2D materials from various thermal sources and dissipating waste heat from electronic devices.
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Affiliation(s)
- Solomon Demiss Negedu
- Department of Metallurgical and Materials Engineering, Indian Institute of Technology Kharagpur, West Bengal, 721302, India.
- Materials Science and Engineering, Jimma Institute of Technology, Jimma University, Jimma, Ethiopia
| | - Raphael Tromer
- Applied Physics Department, University of Campinas, Brazil.
| | - Chinmayee Chowde Gowda
- School of Nano Science and Technology, Indian Institute of Technology Kharagpur, West Bengal, 721302, India
| | - Cristiano F Woellner
- Physics Department, Federal University of Parana, UFPR, Curitiba, PR, 81531-980, Brazil
| | - Femi Emmanuel Olu
- Materials Science and Engineering, Jimma Institute of Technology, Jimma University, Jimma, Ethiopia
| | - Ajit K Roy
- Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright Patterson AFB, OH 45433-7718, USA
| | - Prafull Pandey
- Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Douglas S Galvao
- Applied Physics Department, University of Campinas, Brazil.
- Center for Computational Engineering and Sciences, State University of Campinas, Campinas, SP, 13083-970, Brazil
| | - Pulickel M Ajayan
- Department of Materials Science and Nano Engineering, Rice University, Houston, TX 77005, USA.
| | - Partha Kumbhakar
- Department of Metallurgical and Materials Engineering, Indian Institute of Technology Kharagpur, West Bengal, 721302, India.
| | - Chandra S Tiwary
- Department of Metallurgical and Materials Engineering, Indian Institute of Technology Kharagpur, West Bengal, 721302, India.
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17
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Zeng Z, Braun K, Ge C, Eberle M, Zhu C, Sun X, Yang X, Yi J, Liang D, Wang Y, Huang L, Luo Z, Li D, Pan A, Wang X. Picosecond electrical response in graphene/MoTe 2 heterojunction with high responsivity in the near infrared region. FUNDAMENTAL RESEARCH 2022; 2:405-411. [PMID: 38933404 PMCID: PMC11197620 DOI: 10.1016/j.fmre.2021.09.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 08/28/2021] [Accepted: 09/21/2021] [Indexed: 11/19/2022] Open
Abstract
Understanding the fundamental charge carrier dynamics is of great significance for photodetectors with both high speed and high responsivity. Devices based on two-dimensional (2D) transition metal dichalcogenides can exhibit picosecond photoresponse speed. However, 2D materials naturally have low absorption, and when increasing thickness to gain higher responsivity, the response time usually slows to nanoseconds, limiting their photodetection performance. Here, by taking time-resolved photocurrent measurements, we demonstrated that graphene/MoTe2 van der Waals heterojunctions realize a fast 10 ps photoresponse time owing to the reduced average photocurrent drift time in the heterojunction, which is fundamentally distinct from traditional Dirac semimetal photodetectors such as graphene or Cd3As2 and implies a photodetection bandwidth as wide as 100 GHz. Furthermore, we found that an additional charge carrier transport channel provided by graphene can effectively decrease the photocurrent recombination loss to the entire device, preserving a high responsivity in the near-infrared region. Our study provides a deeper understanding of the ultrafast electrical response in van der Waals heterojunctions and offers a promising approach for the realization of photodetectors with both high responsivity and ultrafast electrical response.
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Affiliation(s)
- Zhouxiaosong Zeng
- School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Kai Braun
- Institute of Physical and Theoretical Chemistry and LISA+, University of Tübingen, Auf der Morgenstelle 18, Tübingen 72076, Germany
| | - Cuihuan Ge
- School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Martin Eberle
- Institute of Physical and Theoretical Chemistry and LISA+, University of Tübingen, Auf der Morgenstelle 18, Tübingen 72076, Germany
| | - Chenguang Zhu
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, College of Materials Science and Engineering, Hunan University, Changsha 410082, China
| | - Xingxia Sun
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, College of Materials Science and Engineering, Hunan University, Changsha 410082, China
| | - Xin Yang
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, College of Materials Science and Engineering, Hunan University, Changsha 410082, China
| | - Jiali Yi
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, College of Materials Science and Engineering, Hunan University, Changsha 410082, China
| | - Delang Liang
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, College of Materials Science and Engineering, Hunan University, Changsha 410082, China
| | - Yufan Wang
- School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Lanyu Huang
- School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Ziyu Luo
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, College of Materials Science and Engineering, Hunan University, Changsha 410082, China
| | - Dong Li
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, College of Materials Science and Engineering, Hunan University, Changsha 410082, China
| | - Anlian Pan
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, College of Materials Science and Engineering, Hunan University, Changsha 410082, China
| | - Xiao Wang
- School of Physics and Electronics, Hunan University, Changsha 410082, China
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18
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Zhao Y, Liu L, Liu S, Wang Y, Li Y, Zhang XD. Electronic and Near-Infrared-II Optical Properties of I-Doped Monolayer MoTe 2: A First-Principles Study. ACS OMEGA 2022; 7:11956-11963. [PMID: 35449971 PMCID: PMC9016853 DOI: 10.1021/acsomega.2c00071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 03/15/2022] [Indexed: 06/14/2023]
Abstract
Near-infrared-II (NIR-II, 1000-1700 nm) fluorescence imaging is widely used for in vivo biological imaging. With the unique electronic structures and capability of band-gap engineering, two-dimensional (2D) materials can be potential candidates for NIR-II imaging. Herein, a theoretical investigation of the electronic structure and optical properties of iodine (I)-doped monolayer MoTe2 systems with different doping concentrations is carried out through simulations to explore their NIR optical properties. The results suggest that the emergence of impurity levels due to I doping effectively reduces the bandwidth of I-doped monolayer MoTe2 systems, and the bandwidth decreases with the increase in the I doping concentration. Although the I and Mo atoms possess clear covalent-bonding features according to the charge density difference, impurity levels induced by the strong hybridization between the I 5p and Mo 4d orbitals cross the Fermi level, making the doped systems exhibit metallic behavior. In addition, with the increase in the I doping concentration, the energy required for electron transition from valence bands to impurity levels gradually decreases, which can be linked to the enhancement of the optical absorption in the red-shifted NIR-II region. Meanwhile, with a higher I doping concentration, the emission spectra, which are the product of the absorption spectra and quasi-Fermi distributions for electrons and holes, can be enhanced in the NIR-II window.
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Affiliation(s)
- Yue Zhao
- Tianjin
Key Laboratory of Brain Science and Neural Engineering, Academy of
Medical Engineering and Translational Medicine, Tianjin University, Tianjin 300072, China
| | - Ling Liu
- Tianjin
Key Laboratory of Brain Science and Neural Engineering, Academy of
Medical Engineering and Translational Medicine, Tianjin University, Tianjin 300072, China
- Department
of Physics, Shanxi Medical University, Taiyuan 030001, China
| | - Shuangjie Liu
- Tianjin
Key Laboratory of Brain Science and Neural Engineering, Academy of
Medical Engineering and Translational Medicine, Tianjin University, Tianjin 300072, China
| | - Yang Wang
- Tianjin
Key Laboratory of Brain Science and Neural Engineering, Academy of
Medical Engineering and Translational Medicine, Tianjin University, Tianjin 300072, China
| | - Yonghui Li
- Department
of Physics and Tianjin Key Laboratory of Low Dimensional Materials
Physics and Preparing Technology, Institute of Advanced Materials
Physics, School of Sciences, Tianjin University, Tianjin 300350, China
| | - Xiao-Dong Zhang
- Tianjin
Key Laboratory of Brain Science and Neural Engineering, Academy of
Medical Engineering and Translational Medicine, Tianjin University, Tianjin 300072, China
- Department
of Physics and Tianjin Key Laboratory of Low Dimensional Materials
Physics and Preparing Technology, Institute of Advanced Materials
Physics, School of Sciences, Tianjin University, Tianjin 300350, China
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19
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Jung E, Park JC, Seo YS, Kim JH, Hwang J, Lee YH. Unusually large exciton binding energy in multilayered 2H-MoTe 2. Sci Rep 2022; 12:4543. [PMID: 35296786 PMCID: PMC8927107 DOI: 10.1038/s41598-022-08692-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 12/23/2021] [Indexed: 11/15/2022] Open
Abstract
Although large exciton binding energies of typically 0.6–1.0 eV are observed for monolayer transition metal dichalcogenides (TMDs) owing to strong Coulomb interaction, multilayered TMDs yield relatively low exciton binding energies owing to increased dielectric screening. Recently, the ideal carrier-multiplication threshold energy of twice the bandgap has been realized in multilayered semiconducting 2H-MoTe2 with a conversion efficiency of 99%, which suggests strong Coulomb interaction. However, the origin of strong Coulomb interaction in multilayered 2H-MoTe2, including the exciton binding energy, has not been elucidated to date. In this study, unusually large exciton binding energy is observed through optical spectroscopy conducted on CVD-grown 2H-MoTe2. To extract exciton binding energy, the optical conductivity is fitted using the Lorentz model to describe the exciton peaks and the Tauc–Lorentz model to describe the indirect and direct bandgaps. The exciton binding energy of 4 nm thick multilayered 2H-MoTe2 is approximately 300 meV, which is unusually large by one order of magnitude when compared with other multilayered TMD semiconductors such as 2H-MoS2 or 2H-MoSe2. This finding is interpreted in terms of small exciton radius based on the 2D Rydberg model. The exciton radius of multilayered 2H-MoTe2 resembles that of monolayer 2H-MoTe2, whereas those of multilayered 2H-MoS2 and 2H-MoSe2 are large when compared with monolayer 2H-MoS2 and 2H-MoSe2. From the large exciton binding energy in multilayered 2H-MoTe2, it is expected to realize the future applications such as room-temperature and high-temperature polariton lasing.
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Affiliation(s)
- Eilho Jung
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea.,Department of Physics, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Jin Cheol Park
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea.,Department of Energy Science, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Yu-Seong Seo
- Department of Physics, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Ji-Hee Kim
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea. .,Department of Energy Science, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea.
| | - Jungseek Hwang
- Department of Physics, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea.
| | - Young Hee Lee
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea. .,Department of Physics, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea. .,Department of Energy Science, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea.
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20
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Ji E, Kim JH, Lee W, Shin JC, Seo H, Ihm K, Park JW, Lee GH. Modulation of electrical properties in MoTe 2 by XeF 2-mediated surface oxidation. NANOSCALE ADVANCES 2022; 4:1191-1198. [PMID: 36131764 PMCID: PMC9417833 DOI: 10.1039/d1na00783a] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 01/04/2022] [Indexed: 06/15/2023]
Abstract
Transition metal dichalcogenides (TMDs) are promising candidates for the semiconductor industry owing to their superior electrical properties. Their surface oxidation is of interest because their electrical properties can be easily modulated by an oxidized layer on top of them. Here, we demonstrate the XeF2-mediated surface oxidation of 2H-MoTe2 (alpha phase MoTe2). MoTe2 exposed to XeF2 gas forms a thin and uniform oxidized layer (∼2.5 nm-thick MoO x ) on MoTe2 regardless of the exposure time (within ∼120 s) due to the passivation effect and simultaneous etching. We used the oxidized layer for contacts between the metal and MoTe2, which help reduce the contact resistance by overcoming the Fermi level pinning effect by the direct metal deposition process. The MoTe2 field-effect transistors (FETs) with a MoO x interlayer exhibited two orders of magnitude higher field-effect hole mobility of 6.31 cm2 V-1 s-1 with a high on/off current ratio of ∼105 than that of the MoTe2 device with conventional metal contacts (0.07 cm2 V-1 s-1). Our work shows a straightforward and effective method for forming a thin oxide layer for MoTe2 devices, applicable for 2D electronics.
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Affiliation(s)
- Eunji Ji
- Department of Material Science and Engineering, Yonsei University Seoul 03722 Korea
| | - Jong Hun Kim
- Department of Material Science and Engineering, Yonsei University Seoul 03722 Korea
- Department of Materials Science and Engineering, Seoul National University Seoul 08826 Korea
- Research Institute of Advanced Materials (RIAM), Seoul National University Seoul 08826 Korea
| | - Wanggon Lee
- Department of Energy Systems Research, Ajou University Suwon 16499 Republic of Korea
| | - June-Chul Shin
- Department of Materials Science and Engineering, Seoul National University Seoul 08826 Korea
| | - Hyungtak Seo
- Department of Materials Science and Engineering, Ajou University Suwon 16499 Republic of Korea
| | - Kyuwook Ihm
- Department of Physics and Pohang Accelerator Laboratory, Pohang University of Science and Technology 37673 Pohang Korea
| | - Jin-Woo Park
- Department of Material Science and Engineering, Yonsei University Seoul 03722 Korea
| | - Gwan-Hyoung Lee
- Department of Materials Science and Engineering, Seoul National University Seoul 08826 Korea
- Research Institute of Advanced Materials (RIAM), Seoul National University Seoul 08826 Korea
- Institute of Engineering Research, Seoul National University Seoul 08826 Korea
- Institute of Applied Physics, Seoul National University Seoul 08826 Korea
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21
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Kim E, Hwang G, Kim D, Won D, Joo Y, Zheng S, Watanabe K, Taniguchi T, Moon P, Kim DW, Sun L, Yang H. Orbital Gating Driven by Giant Stark Effect in Tunneling Phototransistors. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2106625. [PMID: 34825405 DOI: 10.1002/adma.202106625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 11/15/2021] [Indexed: 06/13/2023]
Abstract
Conventional gating in transistors uses electric fields through external dielectrics that require complex fabrication processes. Various optoelectronic devices deploy photogating by electric fields from trapped charges in neighbor nanoparticles or dielectrics under light illumination. Orbital gating driven by giant Stark effect is demonstrated in tunneling phototransistors based on 2H-MoTe2 without using external gating bias or slow charge trapping dynamics in photogating. The original self-gating by light illumination modulates the interlayer potential gradient by switching on and off the giant Stark effect where the dz 2-orbitals of molybdenum atoms play the dominant role. The orbital gating shifts the electronic bands of the top atomic layer of the MoTe2 by up to 100 meV, which is equivalent to modulation of a carrier density of 7.3 × 1011 cm-2 by electrical gating. Suppressing conventional photoconductivity, the orbital gating in tunneling phototransistors achieves low dark current, practical photoresponsivity (3357 AW-1 ), and fast switching time (0.5 ms) simultaneously.
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Affiliation(s)
- Eunah Kim
- Department of Energy Science, Sungkyunkwan University, Suwon, 16419, Korea
| | - Geunwoo Hwang
- Department of Energy Science, Sungkyunkwan University, Suwon, 16419, Korea
| | - Dohyun Kim
- Department of Energy Science, Sungkyunkwan University, Suwon, 16419, Korea
| | - Dongyeun Won
- Department of Energy Science, Sungkyunkwan University, Suwon, 16419, Korea
| | - Yanggeun Joo
- Department of Energy Science, Sungkyunkwan University, Suwon, 16419, Korea
| | - Shoujun Zheng
- Department of Energy Science, Sungkyunkwan University, Suwon, 16419, Korea
| | - Kenji Watanabe
- National Institute for Materials Science, 1-1 Namiki, Tsukuba, 303-0044, Japan
| | - Takashi Taniguchi
- National Institute for Materials Science, 1-1 Namiki, Tsukuba, 303-0044, Japan
| | - Pilkyung Moon
- York University Shanghai and NYU-ECNU Institute of Physics at NYU Shanghai, Shanghai, 200122, China
- School of Computational Sciences, Korea Institute for Advanced Study, Seoul, 02455, Korea
| | - Dong-Wook Kim
- Department of Physics, Ewha Womans University, 52, Ewhayeodae-gil, Seodaemun-gu, Seoul, 03760, Korea
| | - Linfeng Sun
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, 100081, China
| | - Heejun Yang
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Korea
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22
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Guan MX, Liu XB, Chen DQ, Li XY, Qi YP, Yang Q, You PW, Meng S. Optical Control of Multistage Phase Transition via Phonon Coupling in MoTe_{2}. PHYSICAL REVIEW LETTERS 2022; 128:015702. [PMID: 35061482 DOI: 10.1103/physrevlett.128.015702] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 11/28/2021] [Accepted: 12/07/2021] [Indexed: 06/14/2023]
Abstract
The temporal characters of laser-driven phase transition from 2H to 1T^{'} has been investigated in the prototype MoTe_{2} monolayer. This process is found to be induced by fundamental electron-phonon interactions, with an unexpected phonon excitation and coupling pathway closely related to the nonequilibrium relaxation of photoexcited electrons. The order-to-order phase transformation is dissected into three substages, involving energy and momentum scattering processes from optical (A_{1}^{'} and E^{'}) to acoustic phonon modes [LA(M)] in subpicosecond timescale. An intermediate metallic state along the nonadiabatic transition pathway is also identified. These results have profound implications on nonequilibrium phase engineering strategies.
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Affiliation(s)
- Meng-Xue Guan
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Xin-Bao Liu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Da-Qiang Chen
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Xuan-Yi Li
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Ying-Peng Qi
- Center for Ultrafast Science and Technology, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Qing Yang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Pei-Wei You
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Sheng Meng
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
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23
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Tong X, Zhao Y, Zhuo Z, Yang Z, Wang S, Liu Y, Lu N, Li H, Zhai T. Dual‐Regulation of Defect Sites and Vertical Conduction by Spiral Domain for Electrocatalytic Hydrogen Evolution. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202112953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Xipeng Tong
- State Key Laboratory of Materials Processing and Die & Mould Technology and School of Materials Science and Engineering Huazhong University of Science and Technology Wuhan Hubei 430074 P. R. China
| | - Yang Zhao
- State Key Laboratory of Materials Processing and Die & Mould Technology and School of Materials Science and Engineering Huazhong University of Science and Technology Wuhan Hubei 430074 P. R. China
| | - Zhiwen Zhuo
- Anhui Province Key Laboratory of Optoelectric Materials Science and Technology Key Laboratory of Functional Molecular Solids Ministry of Education and Department of Physics Anhui Normal University Wuhu Anhui 241000 P. R. China
| | - Zhenhong Yang
- State Key Laboratory of Materials Processing and Die & Mould Technology and School of Materials Science and Engineering Huazhong University of Science and Technology Wuhan Hubei 430074 P. R. China
| | - Shuzhe Wang
- State Key Laboratory of Materials Processing and Die & Mould Technology and School of Materials Science and Engineering Huazhong University of Science and Technology Wuhan Hubei 430074 P. R. China
| | - Youwen Liu
- State Key Laboratory of Materials Processing and Die & Mould Technology and School of Materials Science and Engineering Huazhong University of Science and Technology Wuhan Hubei 430074 P. R. China
| | - Ning Lu
- Anhui Province Key Laboratory of Optoelectric Materials Science and Technology Key Laboratory of Functional Molecular Solids Ministry of Education and Department of Physics Anhui Normal University Wuhu Anhui 241000 P. R. China
| | - Huiqiao Li
- State Key Laboratory of Materials Processing and Die & Mould Technology and School of Materials Science and Engineering Huazhong University of Science and Technology Wuhan Hubei 430074 P. R. China
| | - Tianyou Zhai
- State Key Laboratory of Materials Processing and Die & Mould Technology and School of Materials Science and Engineering Huazhong University of Science and Technology Wuhan Hubei 430074 P. R. China
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24
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Low-power-consumption CMOS inverter array based on CVD-grown p-MoTe 2 and n-MoS 2. iScience 2021; 24:103491. [PMID: 34917894 PMCID: PMC8668989 DOI: 10.1016/j.isci.2021.103491] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 10/06/2021] [Accepted: 11/19/2021] [Indexed: 12/01/2022] Open
Abstract
Two-dimensional (2D) semi-conductive transition metal dichalcogenides (TMDCs) have shown advantages for logic application. Complementary metal-oxide-semiconductor (CMOS) inverter is an important component in integrated circuits in view of low power consumption. So far, the performance of the reported TMDCs-based CMOS inverters is not satisfactory. Besides, most of the inverters were made of mechanically exfoliated materials, which hinders their reproducible production and large-scale integration in practical application. In this study, we demonstrate a practical approach to fabricate CMOS inverter arrays using large-area p-MoTe2 and n-MoS2, which are grown via chemical vapor deposition method. The current characteristics of the channel materials are balanced by atomic layer depositing Al2O3. Complete logic swing and clear dynamic switching behavior are observed in the inverters. Especially, ultra-low power consumption of ∼0.37 nW is achieved. Our work paves the way for the application of 2D TMDCs materials in large-scale low-power-consumption logic circuits. A practical approach to fabricate large-scale CMOS inverter arrays is demonstrated A method to balance the current characteristics of the channel materials is developed Complete logic swing and clear dynamic switching behavior are observed Ultra-low power consumption of ∼0.37 nW is achieved
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25
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Tong X, Zhao Y, Zhuo Z, Yang Z, Wang S, Liu Y, Lu N, Li H, Zhai T. Dual-Regulation of Defect Sites and Vertical Conduction by Spiral Domain for Electrocatalytic Hydrogen Evolution. Angew Chem Int Ed Engl 2021; 61:e202112953. [PMID: 34871473 DOI: 10.1002/anie.202112953] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Indexed: 11/10/2022]
Abstract
Insufficient active sites and weak vertical conduction are the intrinsic factors that restrict the electrocatalytic HER for transition-metal dichalcogenides. As a prototype, we proposed a model of spiral MoTe2 to optimize collectively the above issues. The conductive atomic force microscopy of an individual spiral reveals that the retentive vertical conduction irrespective of layer thickness benefits from the connected screw dislocation lines between interlayers. Theoretical calculations uncover that the regions near the edge step of the spiral structures more easily form Te vacancies and have lower ΔGH * as extra active sites. A single spiral MoTe2 -based on-chip microcell was fabricated to extract HER activity and achieved an ultrahigh current density of 3000 mA cm-2 at an overpotential of 0.4 V, which is about two orders of magnitude higher than the exfoliated counterpart. Profoundly, this unusual spiral model will initiate a new pathway for triggering other inert catalytic reactions.
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Affiliation(s)
- Xipeng Tong
- State Key Laboratory of Materials Processing and Die & Mould Technology, and School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, P. R. China
| | - Yang Zhao
- State Key Laboratory of Materials Processing and Die & Mould Technology, and School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, P. R. China
| | - Zhiwen Zhuo
- Anhui Province Key Laboratory of Optoelectric Materials Science and Technology, Key Laboratory of Functional Molecular Solids Ministry of Education, and Department of Physics, Anhui Normal University, Wuhu, Anhui, 241000, P. R. China
| | - Zhenhong Yang
- State Key Laboratory of Materials Processing and Die & Mould Technology, and School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, P. R. China
| | - Shuzhe Wang
- State Key Laboratory of Materials Processing and Die & Mould Technology, and School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, P. R. China
| | - Youwen Liu
- State Key Laboratory of Materials Processing and Die & Mould Technology, and School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, P. R. China
| | - Ning Lu
- Anhui Province Key Laboratory of Optoelectric Materials Science and Technology, Key Laboratory of Functional Molecular Solids Ministry of Education, and Department of Physics, Anhui Normal University, Wuhu, Anhui, 241000, P. R. China
| | - Huiqiao Li
- State Key Laboratory of Materials Processing and Die & Mould Technology, and School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, P. R. China
| | - Tianyou Zhai
- State Key Laboratory of Materials Processing and Die & Mould Technology, and School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, P. R. China
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26
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MoTe 2 Field-Effect Transistors with Low Contact Resistance through Phase Tuning by Laser Irradiation. NANOMATERIALS 2021; 11:nano11112805. [PMID: 34835570 PMCID: PMC8620056 DOI: 10.3390/nano11112805] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 10/18/2021] [Accepted: 10/20/2021] [Indexed: 11/17/2022]
Abstract
Due to their extraordinary electrical and physical properties, two-dimensional (2D) transition metal dichalcogenides (TMDs) are considered promising for use in next-generation electrical devices. However, the application of TMD-based devices is limited because of the Schottky barrier interface resulting from the absence of dangling bonds on the TMDs’ surface. Here, we introduce a facile phase-tuning approach for forming a homogenous interface between semiconducting hexagonal (2H) and semi-metallic monoclinic (1T′) molybdenum ditelluride (MoTe2). The formation of ohmic contacts increases the charge carrier mobility of MoTe2 field-effect transistor devices to 16.1 cm2 V−1s−1 with high reproducibility, while maintaining a high on/off current ratio by efficiently improving charge injection at the interface. The proposed method enables a simple fabrication process, local patterning, and large-area scaling for the creation of high-performance 2D electronic devices.
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27
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Han X, Liang X, He D, Jiao L, Wang Y, Zhao H. Photocarrier Dynamics in MoTe 2 Nanofilms with 2 H and Distorted 1 T Lattice Structures. ACS APPLIED MATERIALS & INTERFACES 2021; 13:44703-44710. [PMID: 34494811 DOI: 10.1021/acsami.1c09698] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Molybdenum telluride (MoTe2), an emerging layered two-dimensional (2D) material, possesses excellent phase-changing properties. Previous studies revealed its reversible transition between 2H and 1T' phases with a transition energy as small as 35 meV. Since 1T'-MoTe2 is metallic, it can serve as an electrical contact for semiconducting 2H-MoTe2-based optoelectronic devices. Here, the photocarrier dynamics in MoTe2 nanofilms synthesized by a one-step method and with coexisting multiple phases are investigated by transient absorption measurements. Both the energy relaxation time and the recombination lifetime of the excitons are shorter in the 1T'-MoTe2 compared to its 2H phase. These results provide information on the different photocarrier dynamical properties of these two phases, which is important for future 2D optoelectronic and phase-change electronic devices based on MoTe2.
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Affiliation(s)
- Xiuxiu Han
- Key Laboratory of Luminescence and Optical Information, Ministry of Education, Institute of Optoelectronic Technology, Beijing Jiaotong University, Beijing 100044, China
| | - Xingyao Liang
- Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Dawei He
- Key Laboratory of Luminescence and Optical Information, Ministry of Education, Institute of Optoelectronic Technology, Beijing Jiaotong University, Beijing 100044, China
| | - Liying Jiao
- Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Yongsheng Wang
- Key Laboratory of Luminescence and Optical Information, Ministry of Education, Institute of Optoelectronic Technology, Beijing Jiaotong University, Beijing 100044, China
| | - Hui Zhao
- Department of Physics and Astronomy, The University of Kansas, Lawrence, Kansas 66045, United States
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28
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Choi W, Ahn J, Kim KT, Jin HJ, Hong S, Hwang DK, Im S. Ambipolar Channel p-TMD/n-Ga 2 O 3 Junction Field Effect Transistors and High Speed Photo-sensing in TMD Channel. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2103079. [PMID: 34338384 DOI: 10.1002/adma.202103079] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 05/27/2021] [Indexed: 06/13/2023]
Abstract
Highly crystalline 2D/3D-mixed p-transition metal dichalcogenide (TMD)/n-Ga2 O3 heterojunction devices are fabricated by mechanical exfoliation of each p- and n-type material. N-type β-Ga2 O3 and p-type TMD separately play as a channel for junction field effect transistors (JFETs) with each type of carriers as well as materials for a heterojunction PN diode. The work thus mainly focuses on such ambipolar channel transistors with two different types of channel in a single device architecture. For more extended applications, the transparency of high energy band gap β-Ga2 O3 (Eg ≈ 4.8 eV) is taken advantage of, firstly to measure the electrical energy gap of p-TMDs receiving visible or near infrared (NIR) photons through the β-Ga2 O3 . Next, the p-TMD/n-Ga2 O3 JFETs are put to high speed photo-sensing which is achieved from the p-TMD channel under reverse bias voltages on n-Ga2 O3 . The photo-switching cutoff frequency appears to be ≈16 and 29 kHz for visible red and NIR illuminations, respectively, on the basis of -3 dB photoelectric power loss. Such a high switching speed of the JFET is attributed to the fast transport of photo-carriers in TMD channels. The 2D/3D-mixed ambipolar channel JFETs and their photo-sensing applications are regarded novel, promising, and practically easy to achieve.
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Affiliation(s)
- Wonjun Choi
- Van der Waals Materials Research Center, Department of Physics, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Jongtae Ahn
- Center of Opto-Electronic Materials and Devices, Post-Silicon Semiconductor Institute, Korea Institute of Science and Technology (KIST), 85, Hoegi-ro, Dongdaemun-gu, Seoul, 02792, Republic of Korea
| | - Ki-Tae Kim
- Van der Waals Materials Research Center, Department of Physics, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Hye-Jin Jin
- Van der Waals Materials Research Center, Department of Physics, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Sungjae Hong
- Van der Waals Materials Research Center, Department of Physics, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Do Kyung Hwang
- Center of Opto-Electronic Materials and Devices, Post-Silicon Semiconductor Institute, Korea Institute of Science and Technology (KIST), 85, Hoegi-ro, Dongdaemun-gu, Seoul, 02792, Republic of Korea
| | - Seongil Im
- Van der Waals Materials Research Center, Department of Physics, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
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29
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Grzeszczyk M, Szpakowski J, Slobodeniuk AO, Kazimierczuk T, Bhatnagar M, Taniguchi T, Watanabe K, Kossacki P, Potemski M, Babiński A, Molas MR. The optical response of artificially twisted MoS[Formula: see text] bilayers. Sci Rep 2021; 11:17037. [PMID: 34426607 PMCID: PMC8382769 DOI: 10.1038/s41598-021-95700-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 07/27/2021] [Indexed: 11/17/2022] Open
Abstract
Two-dimensional layered materials offer the possibility to create artificial vertically stacked structures possessing an additional degree of freedom-the interlayer twist. We present a comprehensive optical study of artificially stacked bilayers (BLs) MoS[Formula: see text] encapsulated in hexagonal BN with interlayer twist angle ranging from 0[Formula: see text] to 60[Formula: see text] using Raman scattering and photoluminescence spectroscopies. It is found that the strength of the interlayer coupling in the studied BLs can be estimated using the energy dependence of indirect emission versus the A[Formula: see text]-E[Formula: see text] energy separation. Due to the hybridization of electronic states in the valence band, the emission line related to the interlayer exciton is apparent in both the natural (2H) and artificial (62[Formula: see text]) MoS[Formula: see text] BLs, while it is absent in the structures with other twist angles. The interlayer coupling energy is estimated to be of about 50 meV. The effect of temperature on energies and intensities of the direct and indirect emission lines in MoS[Formula: see text] BLs is also quantified.
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Affiliation(s)
- M. Grzeszczyk
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - J. Szpakowski
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - A. O. Slobodeniuk
- Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague 2, Czech Republic
| | - T. Kazimierczuk
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - M. Bhatnagar
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - T. Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044 Japan
| | - K. Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044 Japan
| | - P. Kossacki
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - M. Potemski
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25, Avenue des Martyrs, 38042 Grenoble, France
| | - A. Babiński
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - M. R. Molas
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
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30
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Yang L, Wu H, Zhang L, Zhang G, Li H, Jin W, Zhang W, Chang H. Tunable and Robust Near-Room-Temperature Intrinsic Ferromagnetism of a van der Waals Layered Cr-Doped 2H-MoTe 2 Semiconductor with an Out-of-Plane Anisotropy. ACS APPLIED MATERIALS & INTERFACES 2021; 13:31880-31890. [PMID: 34182752 DOI: 10.1021/acsami.1c07680] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The intrinsically nonmagnetic feature of van der Waals (vdW) layered transition-metal dichalcogenide (TMDC) semiconductors limits the spintronic applications of these semiconductors. In this paper, we demonstrate a facile Te flux strategy to induce intrinsic ferromagnetism in the vdW layered 2H-MoTe2 semiconductor by magnetic chromium (Cr) doping. The Curie temperature (Tc) and saturation magnetization (Ms) can be well tuned by adjusting the Cr doping concentration. A notable Tc up to 275 K can be achieved for the vdW layered Cr-doped 2H-MoTe2 bulk crystals, which is much higher than that of recently reported van der Waals ferromagnetic semiconductors (Tc is mostly less than 70 K), in contrast to the diamagnetic feature of the pristine MoTe2. Meanwhile, the highest Ms of the vdW layered Cr-doped 2H-MoTe2 bulk crystals can reach 4.78 emu g-1, which is stronger than most values reported for magnetic-element-doped van der Waals materials. In addition, all of the as-grown semiconducting Cr-doped 2H-MoTe2 (Cr-2H-MoTe2) single crystals display a large magnetic anisotropy with an out-of-plane easy axis of magnetization. The observed ferromagnetism in the Cr-2H-MoTe2 has intrinsic characteristics, which can be mainly attributed to the spin polarization caused by Cr doping as confirmed by the density functional theory (DFT) calculations. Our approach offers an avenue to tune the ferromagnetism in the vdW layered semiconductor and explore its diverse spintronic and magnetoelectric applications.
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Affiliation(s)
- Li Yang
- Center for Joining and Electronic Packaging, State Key Laboratory of Material Processing and Die & Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China
- Shenzhen R&D Center of Huazhong University of Science and Technology (HUST), Shenzhen 518000, China
- Institute for Quantum Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China
| | - Hao Wu
- Center for Joining and Electronic Packaging, State Key Laboratory of Material Processing and Die & Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China
- Shenzhen R&D Center of Huazhong University of Science and Technology (HUST), Shenzhen 518000, China
- Institute for Quantum Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China
| | - Liang Zhang
- School of Science and Center for Materials Science and Engineering, Guangxi University of Science and Technology, Liuzhou 545026, China
| | - Gaojie Zhang
- Center for Joining and Electronic Packaging, State Key Laboratory of Material Processing and Die & Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China
- Shenzhen R&D Center of Huazhong University of Science and Technology (HUST), Shenzhen 518000, China
- Institute for Quantum Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China
| | - Hongda Li
- School of Science and Center for Materials Science and Engineering, Guangxi University of Science and Technology, Liuzhou 545026, China
| | - Wen Jin
- Center for Joining and Electronic Packaging, State Key Laboratory of Material Processing and Die & Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China
- Shenzhen R&D Center of Huazhong University of Science and Technology (HUST), Shenzhen 518000, China
- Institute for Quantum Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China
| | - Wenfeng Zhang
- Center for Joining and Electronic Packaging, State Key Laboratory of Material Processing and Die & Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China
- Shenzhen R&D Center of Huazhong University of Science and Technology (HUST), Shenzhen 518000, China
- Institute for Quantum Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China
| | - Haixin Chang
- Center for Joining and Electronic Packaging, State Key Laboratory of Material Processing and Die & Mold Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China
- Shenzhen R&D Center of Huazhong University of Science and Technology (HUST), Shenzhen 518000, China
- Institute for Quantum Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China
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Afzal AM, Iqbal MZ, Dastgeer G, Ahmad AU, Park B. Highly Sensitive, Ultrafast, and Broadband Photo-Detecting Field-Effect Transistor with Transition-Metal Dichalcogenide van der Waals Heterostructures of MoTe 2 and PdSe 2. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2003713. [PMID: 34105276 PMCID: PMC8188193 DOI: 10.1002/advs.202003713] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 02/10/2021] [Indexed: 05/11/2023]
Abstract
Recently, van der Waals heterostructures (vdWHs) based on transition-metal dichalcogenides (TMDs) have attracted significant attention owing to their superior capabilities and multiple functionalities. Herein, a novel vdWH field-effect transistor (FET) composed of molybdenum ditelluride (MoTe2 ) and palladium diselenide (PdSe2 ) is studied for highly sensitive photodetection performance in the broad visible and near-infrared (VNIR) region. A high rectification ratio of 6.3 × 105 is obtained, stemming from the sharp interface and low Schottky barriers of the MoTe2 /PdSe2 vdWHs. It is also successfully demonstrated that the vdWH FET exhibits highly sensitive photo-detecting abilities, such as noticeably high photoresponsivity (1.24 × 105 A W-1 ), specific detectivity (2.42 × 1014 Jones), and good external quantum efficiency (3.5 × 106 ), not only due to the intra-TMD band-to-band transition but also due to the inter-TMD charge transfer (CT) transition. Further, rapid rise (16.1 µs) and decay (31.1 µs) times are obtained under incident light with a wavelength of 2000 nm due to the CT transition, representing an outcome one order of magnitude faster than values currently in the literature. Such TMD-based vdWH FETs would improve the photo-gating characteristics and provide a platform for the realization of a highly sensitive photodetector in the broad VNIR region.
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Affiliation(s)
- Amir Muhammad Afzal
- Department of Electrical and Biological PhysicsKwangwoon UniversityWolgye‐DongSeoul01897South Korea
| | - Muhammad Zahir Iqbal
- Nanotechnology Research Laboratory, Faculty of Engineering SciencesGIK Institute of Engineering Sciences and TechnologyTopiKhyber Pakhtunkhwa23640Pakistan
| | - Ghulam Dastgeer
- School of PhysicsPeking UniversityBeijing100871China
- IBS Center for Integrated Nanostructure PhysicsSungkyunkwan UniversitySuwon16419South Korea
| | - Aqrab ul Ahmad
- School of Physics and School of MicroelectronicsDalian University of TechnologyDalian116000China
| | - Byoungchoo Park
- Department of Electrical and Biological PhysicsKwangwoon UniversityWolgye‐DongSeoul01897South Korea
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32
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Adhikari B, Limbu TB, Vinodgopal K, Yan F. Atmospheric-pressure CVD growth of two-dimensional 2H- and 1 T'-MoTe 2films with high-performance SERS activity. NANOTECHNOLOGY 2021; 32:335701. [PMID: 33971633 DOI: 10.1088/1361-6528/abff8f] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Accepted: 05/10/2021] [Indexed: 06/12/2023]
Abstract
Two-dimensional (2D) molybdenum ditelluride (MoTe2) is a member of the transition-metal dichalcogenides family, which is an especially promising platform for surface-enhanced Raman scattering (SERS) applications, due to its excellent electronic properties. However, the synthesis of large-area highly crystalline 2D MoTe2with controllable polymorphism is a huge challenge due to the small free energy difference (∼40 meV per unit cell) between semiconducting 2H-MoTe2and semi-metallic 1 T'-MoTe2. Herein, we report an optimized route for the synthesis of 2H- and 1 T'-MoTe2films by atmospheric-pressure chemical vapor deposition. The SERS study of the as-grown MoTe2films was carried out using methylene blue (MB) as a probe molecule. The Raman enhancement factor on 1 T'-MoTe2was found to be three times higher than that on 2H-MoTe2and the 1 T'-MoTe2film is an efficient Raman-enhancing substrate that can be used to detect MB at nanomolar concentrations. Our study also imparts knowledge on the significance of a suitable combination of laser excitation wavelength and molecule-material platform for achieving ultrasensitive SERS-based chemical detection.
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Affiliation(s)
- Bikram Adhikari
- Department of Chemistry and Biochemistry, North Carolina Central University, Durham, NC 27707, United States of America
| | - Tej B Limbu
- Department of Chemistry and Biochemistry, North Carolina Central University, Durham, NC 27707, United States of America
| | - Kizhanipuram Vinodgopal
- Department of Chemistry and Biochemistry, North Carolina Central University, Durham, NC 27707, United States of America
| | - Fei Yan
- Department of Chemistry and Biochemistry, North Carolina Central University, Durham, NC 27707, United States of America
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33
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Xie Y, Wu E, Fan S, Geng G, Hu X, Xu L, Wu S, Liu J, Zhang D. Modulation of MoTe 2/MoS 2 van der Waals heterojunctions for multifunctional devices using N 2O plasma with an opposite doping effect. NANOSCALE 2021; 13:7851-7860. [PMID: 33881030 DOI: 10.1039/d0nr08814e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
van der Waals layered heterojunctions have a variety of band offsets that open up possibilities for a wide range of novel and multifunctional devices. However, due to their poor pristine carrier concentrations and limited band modulation methods, multifunctional p-n heterojunctions are very difficult to achieve. In this report, we developed a highly effective N2O plasma process to treat MoTe2/MoS2 heterojunctions. This allowed us to adjust the hole and electron concentrations in the two materials independently and simultaneously. More importantly, for the first time, we were able to create opposite doping on the two sides of the junction through a single-step treatment. With a very wide doping range from pristine to degenerate levels, a MoTe2/MoS2 heterojunction can be modulated to behave as a forward rectifying diode with enhanced rectifying ratio and as a tunneling transistor with negative differential resistance at room temperature. The new approach provides an effective and generic doping scheme for heterojunctions to construct versatile and multifunctional electronic devices.
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Affiliation(s)
- Yuan Xie
- State Key Laboratory of Precision Measurement Technology and Instruments, School of Precision Instruments and Opto-electronics Engineering, Tianjin University, No. 92 Weijin Road, Tianjin, 300072, China.
| | - Enxiu Wu
- State Key Laboratory of Precision Measurement Technology and Instruments, School of Precision Instruments and Opto-electronics Engineering, Tianjin University, No. 92 Weijin Road, Tianjin, 300072, China.
| | - Shuangqing Fan
- School of Electronic and Information Engineering, Qingdao University, Qingdao 266071, China
| | - Guangyu Geng
- State Key Laboratory of Precision Measurement Technology and Instruments, School of Precision Instruments and Opto-electronics Engineering, Tianjin University, No. 92 Weijin Road, Tianjin, 300072, China.
| | - Xiaodong Hu
- State Key Laboratory of Precision Measurement Technology and Instruments, School of Precision Instruments and Opto-electronics Engineering, Tianjin University, No. 92 Weijin Road, Tianjin, 300072, China.
| | - Linyan Xu
- State Key Laboratory of Precision Measurement Technology and Instruments, School of Precision Instruments and Opto-electronics Engineering, Tianjin University, No. 92 Weijin Road, Tianjin, 300072, China.
| | - Sen Wu
- State Key Laboratory of Precision Measurement Technology and Instruments, School of Precision Instruments and Opto-electronics Engineering, Tianjin University, No. 92 Weijin Road, Tianjin, 300072, China.
| | - Jing Liu
- State Key Laboratory of Precision Measurement Technology and Instruments, School of Precision Instruments and Opto-electronics Engineering, Tianjin University, No. 92 Weijin Road, Tianjin, 300072, China.
| | - Daihua Zhang
- State Key Laboratory of Precision Measurement Technology and Instruments, School of Precision Instruments and Opto-electronics Engineering, Tianjin University, No. 92 Weijin Road, Tianjin, 300072, China.
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34
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Xu X, Pan Y, Liu S, Han B, Gu P, Li S, Xu W, Peng Y, Han Z, Chen J, Gao P, Ye Y. Seeded 2D epitaxy of large-area single-crystal films of the van der Waals semiconductor 2H MoTe 2. Science 2021; 372:195-200. [PMID: 33833124 DOI: 10.1126/science.abf5825] [Citation(s) in RCA: 87] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 03/04/2021] [Indexed: 12/23/2022]
Abstract
The integration of two-dimensional (2D) van der Waals semiconductors into silicon electronics technology will require the production of large-scale, uniform, and highly crystalline films. We report a route for synthesizing wafer-scale single-crystalline 2H molybdenum ditelluride (MoTe2) semiconductors on an amorphous insulating substrate. In-plane 2D-epitaxy growth by tellurizing was triggered from a deliberately implanted single seed crystal. The resulting single-crystalline film completely covered a 2.5-centimeter wafer with excellent uniformity. The 2H MoTe2 2D single-crystalline film can use itself as a template for further rapid epitaxy in a vertical manner. Transistor arrays fabricated with the as-prepared 2H MoTe2 single crystals exhibited high electrical performance, with excellent uniformity and 100% device yield.
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Affiliation(s)
- Xiaolong Xu
- State Key Laboratory for 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
| | - Yu Pan
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Shuai Liu
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Bo Han
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, China.,International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Pingfan Gu
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Siheng Li
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Wanjin Xu
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Yuxuan Peng
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Zheng Han
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 03006, China.,Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 03006, China
| | - Ji Chen
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, 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 Laboratory for 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.,Peking University Yangtze Delta Institute of Optoelectronics, Nantong 226010, Jiangsu, China
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35
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Wu Q, Fu X, Yang K, Wu H, Liu L, Zhang L, Tian Y, Yin LJ, Huang WQ, Zhang W, Wong PKJ, Zhang L, Wee ATS, Qin Z. Promoting a Weak Coupling of Monolayer MoSe 2 Grown on (100)-Faceted Au Foil. ACS NANO 2021; 15:4481-4489. [PMID: 33656862 DOI: 10.1021/acsnano.0c08513] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
As a two-dimensional semiconductor with many physical properties, including, notably, layer-controlled electronic bandgap and coupled spin-valley degree of freedom, monolayer MoSe2 is a strong candidate material for next-generation opto- and valley-electronic devices. However, due to substrate effects such as lattice mismatch and dielectric screening, preserving the monolayer's intrinsic properties remains challenging. This issue is generally significant for metallic substrates whose active surfaces are commonly utilized to achieve direct chemical or physical vapor growth of the monolayer films. Here, we demonstrate high-temperature-annealed Au foil with well-defined (100) facets as a weakly interacting substrate for atmospheric pressure chemical vapor deposition of highly crystalline monolayer MoSe2. Low-temperature scanning tunneling microscopy/spectroscopy measurements reveal a honeycomb structure of MoSe2 with a quasi-particle bandgap of 1.96 eV, a value comparable with other weakly interacting systems such as MoSe2/graphite. Density functional theory calculations indicate that the Au(100) surface exhibits the preferred energetics to electronically decouple from MoSe2, compared with the (110) and (111) crystal planes. This weak coupling is critical for the easy transfer of monolayers to another host substrate. Our study demonstrates a practical means to produce high-quality monolayers of transition-metal dichalcogenides, viable for both fundamental and application studies.
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Affiliation(s)
- Qilong Wu
- Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha 410082, People's Republic of China
| | - Xiaoshuai Fu
- Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha 410082, People's Republic of China
| | - Ke Yang
- Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha 410082, People's Republic of China
| | - Hongyu Wu
- Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha 410082, People's Republic of China
| | - Li Liu
- Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha 410082, People's Republic of China
| | - Li Zhang
- Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha 410082, People's Republic of China
| | - Yuan Tian
- Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha 410082, People's Republic of China
| | - Long-Jing Yin
- Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha 410082, People's Republic of China
| | - Wei-Qing Huang
- Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha 410082, People's Republic of China
| | - Wen Zhang
- School of Microelectronics & School of Electronics and Information, Northwestern Polytechnical University, Xi'an 710072, People's Republic of China
| | - Ping Kwan Johnny Wong
- School of Microelectronics & School of Electronics and Information, Northwestern Polytechnical University, Xi'an 710072, People's Republic of China
| | - Lijie Zhang
- Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha 410082, People's Republic of China
| | - Andrew T S Wee
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117551, Singapore
- Centre for Advanced 2D Materials (CA2DM) and Graphene Research Centre (GRC), National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore
| | - Zhihui Qin
- Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha 410082, People's Republic of China
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36
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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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37
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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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38
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Wang M, Li D, Liu K, Guo Q, Wang S, Li X. Nonlinear Optical Imaging, Precise Layer Thinning, and Phase Engineering in MoTe 2 with Femtosecond Laser. ACS NANO 2020; 14:11169-11177. [PMID: 32816458 DOI: 10.1021/acsnano.0c02649] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The control of layer thickness and phase structure in two-dimensional transition metal dichalcogenides (2D TMDCs) like MoTe2 has recently gained much attention due to their broad applications in nanoelectronics and nanophotonics. Continuous-wave laser-based thermal treatment has been demonstrated to realize layer thinning and phase engineering in MoTe2, but requires long heating time and is largely influenced by the thermal dissipation of the substrate. The ultrafast laser produces a different response but is yet to be explored. In this work, we report the nonlinear optical interactions between MoTe2 crystals and femtosecond (fs) laser, where we have realized the nonlinear optical characterization, precise layer thinning, and phase transition in MoTe2 using a single fs laser platform. By using the fs laser with a low fluence as an excitation light source, we observe the strong nonlinear optical signals of second-harmonic generation and four-wave mixing in MoTe2, which can be used to identify the odd-even layers and layer numbers, respectively. With increasing the laser fluence to the ablation threshold (Fth), we achieve layer-by-layer removal of MoTe2, while 2H-to-1T' phase transition occurs with a higher laser fluence (2Fth to 3Fth). Moreover, we obtain highly ordered subwavelength nanoripples on both the thick and few-layer MoTe2 with a controlled fluence, which can be attributed to the fs laser-induced reorganization of the molten plasma. Our study provides a simple and efficient ultrafast laser-based approach capable of characterizing the structures and modifying the physical properties of 2D TMDCs.
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Affiliation(s)
- Mengmeng Wang
- Laser Micro/Nano Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Dawei Li
- Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0299, United States
| | - Kun Liu
- School of Optoelectronic Engineering and Instrument Science, Dalian University of Technology, Dalian, Liaoning 116024, China
| | - Qitong Guo
- Laser Micro/Nano Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Sumei Wang
- Laser Micro/Nano Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
- Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Xin Li
- Laser Micro/Nano Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
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39
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Yim D, Lee DE, So Y, Choi C, Son W, Jang K, Yang CS, Kim JH. Sustainable Nanosheet Antioxidants for Sepsis Therapy via Scavenging Intracellular Reactive Oxygen and Nitrogen Species. ACS NANO 2020; 14:10324-10336. [PMID: 32806029 DOI: 10.1021/acsnano.0c03807] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Sepsis is an aberrant systemic inflammatory response mediated by excessive production of reactive oxygen species (ROS) and reactive nitrogen species (RNS). Developing an efficient antioxidant therapy for sepsis via scavenging ROS and RNS remains a big challenge owing to the insufficient activity and sustainability of conventional antioxidants. Herein, biocompatible transition-metal dichalcogenide antioxidants with excellent scavenging activity and sustainability for H2O2, O2•-, OH•, and nitric oxide are developed for effective sepsis treatment. WS2, MoSe2, and WSe2 nanosheets exfoliated and functionalized with a biocompatible polymer effectively scavenge mitochondrial and intracellular ROS and RNS in inflammatory cells. Among the nanosheets, WS2 most efficiently suppresses the excessive secretion of inflammatory cytokines along with scavenging ROS and RNS without affecting the expression levels of the anti-inflammatory cytokine and ROS-producing enzymes. The WS2 nanosheets significantly improve the survival rate up to 90% for severely septic mice by reducing systemic inflammation. The pharmacokinetics suggests that the WS2 nanosheets can be excreted from mice 3 days after intravenous injection. This work demonstrates the potential of therapeutic nanosheet antioxidants for effective treatment of ROS and RNS-related diseases.
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Affiliation(s)
- DaBin Yim
- Department of Chemical Engineering, Hanyang University, Ansan 15588, Republic of Korea
| | - Da-Eun Lee
- Department of Molecular and Life Science, Hanyang University, Ansan 15588, Republic of Korea
| | - Yoonhee So
- Department of Chemical Engineering, Hanyang University, Ansan 15588, Republic of Korea
| | - Chanhee Choi
- Department of Chemical Engineering, Hanyang University, Ansan 15588, Republic of Korea
| | - Wooic Son
- Department of Molecular and Life Science, Hanyang University, Ansan 15588, Republic of Korea
| | - Kiseok Jang
- Department of Pathology, Hanyang University College of Medicine, Seoul 04763, Republic of Korea
| | - Chul-Su Yang
- Department of Molecular and Life Science, Hanyang University, Ansan 15588, Republic of Korea
- Department of Bionano Technology, Hanyang University, Seoul 04763, Republic of Korea
| | - Jong-Ho Kim
- Department of Chemical Engineering, Hanyang University, Ansan 15588, Republic of Korea
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40
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Chen F, Cui A, Wang X, Gao C, Xu L, Jiang K, Zhang J, Hu Z, Chu J. Lattice vibration characteristics in layered InSe films and the electronic behavior of field-effect transistors. NANOTECHNOLOGY 2020; 31:335702. [PMID: 32344392 DOI: 10.1088/1361-6528/ab8df1] [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
Understanding how temperature affects the structural and electronic properties for two-dimensional (2D) semiconductors could promote the application and development of nanoelectronic devices. Here, the temperature dependence of lattice structure for indium selenide (InSe) nanosheets and the corresponding electronic properties of 3 nm indium-deposited InSe field-effect transistors (FETs) are systematically demonstrated. Analyses of Raman spectra suggest that the difference of phonon frequency (Δω) for the A[Formula: see text] mode is found to be 3.14 cm-1, which is larger than that of the E[Formula: see text] mode due to the stronger electron-phonon coupling for the A[Formula: see text] mode. The device performance based on indium-deposited InSe is systematically explained using Kelvin probe force microscopy (KPFM) and the predicted energy band structure. Furthermore, FETs based on temperature and variable thickness InSe flakes are designed as applicable devices. Our findings are of fundamental importance to explain the underlying physics in intrinsic InSe transistors and improve further applications.
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Affiliation(s)
- Fangfang Chen
- Technical Center for Multifunctional Magneto-Optical Spectroscopy (Shanghai), Engineering Research Center of Nanophotonics Advanced Instrument (Ministry of Education), Department of Materials, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, People's Republic of China
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41
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Wan X, Li H, Chen K, Xu J. Towards Scalable Fabrications and Applications of 2D Layered Material-based Vertical and Lateral Heterostructures. Chem Res Chin Univ 2020. [DOI: 10.1007/s40242-020-0200-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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42
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Kumar D, Singh B, Kumar R, Kumar M, Kumar P. Anisotropic electron-photon-phonon coupling in layered MoS 2. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:415702. [PMID: 32512557 DOI: 10.1088/1361-648x/ab9a7a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 06/08/2020] [Indexed: 06/11/2023]
Abstract
Transition metal dichalcogenide, MoS2has attracted a lot of attention recently owing to its tunable visible range band gap, and anisotropic electronic and transport properties. Here, we report comprehensive inelastic light scattering measurements on both chemical vapor deposition grown (horizontally and vertically aligned) flakes, and mechanically exfoliated flakes of single crystal MoS2. We probe the anisotropic optical response by studying the polarization dependence intensity of the Raman active phonon modes as a function of different incident photon energy and flake thickness. Our polarization dependent Raman studies reveal strong anisotropic behavior reflected in the anomalous renormalization of the modes intensity as a function of flake thickness, phonons and photon energy. Our observations reflect the strong anisotropic light-matter interaction in this high crystalline symmetric layered MoS2system, especially for the in-plane vibrations, crucial for understanding as well as future applications of these materials.
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Affiliation(s)
- Deepu Kumar
- School of Basic Sciences, Indian Institute of Technology Mandi, Mandi-175005, India
| | - Birender Singh
- School of Basic Sciences, Indian Institute of Technology Mandi, Mandi-175005, India
| | - Rahul Kumar
- Department of Electrical Engineering, Indian Institute of Technology Jodhpur, Jodhpur-342037, India
| | - Mahesh Kumar
- Department of Electrical Engineering, Indian Institute of Technology Jodhpur, Jodhpur-342037, India
| | - Pradeep Kumar
- School of Basic Sciences, Indian Institute of Technology Mandi, Mandi-175005, India
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43
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Yang Y, Shang J, Gao H, Sun Q, Kou L, Chen ZG, Zou J. Intercalation-Induced Disintegrated Layer-By-Layer Growth of Ultrathin Ternary Mo(Te 1-xS x) 2 Plates. ACS APPLIED MATERIALS & INTERFACES 2020; 12:30980-30989. [PMID: 32515585 DOI: 10.1021/acsami.0c07342] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Nanometer-thick transition-metal dichalcogenides (TMDs) have attracted increasing research interest because of their exotic physical properties, but their high-yield and large-scale synthesis remains a challenge for their practical device applications. In this study, we realize the high-yield synthesis of nanometer-thick single-crystalline Mo(Te1-xSx)2 plates by a facile chemical vapor deposition method. Adding S powders in the precursors can result in the products varying from well-faceted MoTe2 hexagonal plates to irregular Mo(Te1-xSx)2 plates with randomly stacked nanometer-thick layer steps. Moreover, their lateral dimension increases from several μm for binary MoTe2 to several tens of μm for ternary Mo(Te1-xSx)2. More interestingly, such irregular Mo(Te1-xSx)2 plates can form few layers by ultrasonic exfoliation. Our detailed electron microscopy analyses show that three kinds of S forms influence the ternary growth. In particular, elemental S8 intercalations play an important role in the growth and exfoliation of ultrathin Mo(Te1-xSx)2 plates. This study enriches the fundamental understanding of zero-valent intercalation in TMDs and provides a new insight into secure high-yield nanometer-thick TMDs, which is critical for practical applications.
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Affiliation(s)
- Yuzhe Yang
- School of Mechanical and Mining Engineering, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Jing Shang
- School of Chemistry, Physics and Mechanical Engineering Faculty, Queensland University of Technology, Gardens Point Campus, Brisbane, Queensland 4001, Australia
| | - Han Gao
- School of Mechanical and Mining Engineering, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Qiang Sun
- School of Mechanical and Mining Engineering, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Liangzhi Kou
- School of Chemistry, Physics and Mechanical Engineering Faculty, Queensland University of Technology, Gardens Point Campus, Brisbane, Queensland 4001, Australia
| | - Zhi-Gang Chen
- School of Mechanical and Mining Engineering, The University of Queensland, St. Lucia, Queensland 4072, Australia
- Centre for Future Materials, University of Southern Queensland, Springfield Central, Queensland 4300, Australia
| | - Jin Zou
- School of Mechanical and Mining Engineering, The University of Queensland, St. Lucia, Queensland 4072, Australia
- Centre for Microscopy and Microanalysis, The University of Queensland, St. Lucia, Queensland 4072, Australia
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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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45
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Lim SY, Lee JU, Kim JH, Liang L, Kong X, Nguyen TTH, Lee Z, Cho S, Cheong H. Polytypism in few-layer gallium selenide. NANOSCALE 2020; 12:8563-8573. [PMID: 32248214 DOI: 10.1039/d0nr00165a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Gallium selenide (GaSe) is one of the layered group-III metal monochalcogenides, which has an indirect bandgap in the monolayer and a direct bandgap in bulk unlike other conventional transition metal dichalcogenides (TMDs) such as MoX2 and WX2 (X = S and Se). Four polytypes of bulk GaSe, designated as β-, ε-, γ-, and δ-GaSe, have been reported. Since different polytypes result in different optical and electrical properties even with the same thickness, identifying the polytype is essential in utilizing this material for various optoelectronic applications. We performed polarized Raman measurements on GaSe and found different ultra-low-frequency Raman spectra of inter-layer vibrational modes even with the same thickness due to different stacking sequences of the polytypes. By comparing the ultra-low-frequency Raman spectra with the theoretical calculations and high-resolution electron microscopy measurements, we established the correlation between the ultra-low-frequency Raman spectra and the stacking sequences of trilayer GaSe. We further found that the AB-type stacking is more stable than the AA'-type stacking in GaSe.
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Affiliation(s)
- Soo Yeon Lim
- Department of Physics, Sogang University, Seoul 04107, Korea.
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46
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Microwave synthesized dry leaf-like mesoporous MoSe2 nanostructure as an efficient catalyst for enhanced hydrogen evolution and supercapacitor applications. Microchem J 2020. [DOI: 10.1016/j.microc.2019.104446] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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47
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Yang SH, Lin CY, Chang YM, Li M, Lee KC, Chen CF, Yang FS, Lien CH, Ueno K, Watanabe K, Taniguchi T, Tsukagoshi K, Lin YF. Oxygen-Sensitive Layered MoTe 2 Channels for Environmental Detection. ACS APPLIED MATERIALS & INTERFACES 2019; 11:47047-47053. [PMID: 31746187 DOI: 10.1021/acsami.9b15036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The oxygen (O2)-dependent resistance change of multilayered molybdenum ditelluride (MoTe2) channels was characterized. A variation of the channel resistance could reproducibly determine relative O2 content (denoted as the O2 index). We found that Joule heating in a layered MoTe2 field-effect transistor caused the O2 index to decrease drastically from 100 to 12.1% in back gate modulation. Furthermore, Joule heating caused effective O2 desorption from the MoTe2 surface and repeatable O2 detection by multilayered MoTe2 channels was realized. This work not only explored the influence of O2 on the electrical properties of multilayered MoTe2 channels but also revealed that MoTe2 channels are promising for sensing O2 in an environmental condition.
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Affiliation(s)
- Shih-Hsien Yang
- International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education, Institute of Microscale Optoelectronics , Shenzhen University , Shenzhen 518060 , China
| | - Che-Yi Lin
- Department of Electrophysics , National Chiao Tung University , Hsinchu 30010 , Taiwan
| | | | | | - Ko-Chun Lee
- Department of Electrical Engineering and Institute of Electronic Engineering , National Tsing Hua University , Hsinchu 30010 , Taiwan
| | | | - Feng-Shou Yang
- Department of Electrical Engineering and Institute of Electronic Engineering , National Tsing Hua University , Hsinchu 30010 , Taiwan
| | - Chen-Hsin Lien
- Department of Electrical Engineering and Institute of Electronic Engineering , National Tsing Hua University , Hsinchu 30010 , Taiwan
| | - Keiji Ueno
- Department of Chemistry, Graduate School of Science and Engineering , Saitama University , Saitama 338-8570 , Japan
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Han X. 2D MoTe 2 film as a saturable absorber for a wavelength-tunable ultrafast fiber laser. APPLIED OPTICS 2019; 58:8390-8395. [PMID: 31873320 DOI: 10.1364/ao.58.008390] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 09/24/2019] [Indexed: 06/10/2023]
Abstract
We have demonstrated the realization of wavelength-tunable pulse outputs in a mode-locked fiber laser by utilizing 2D ${{\rm MoTe}_2}$MoTe2 film as the saturable absorber (SA). The SA is synthesized by coating 2D ${{\rm MoTe}_2}$MoTe2 film on the pinhole of the fiber pigtail and it can work stably at the mode-locking state for several weeks, indicating that the 2D ${{\rm MoTe}_2}$MoTe2 film is a suitable SA for ultrafast optics. The ${{\rm MoTe}_2}$MoTe2 film mode-locked fiber laser can operate well at a wide spectral band, and the central wavelength of pulses is tunable in the range from 1530 to 1560 nm, which is attributed to the polarization-sensitive feature of the proposed SA. Our new SA will benefit high-power pulsed lasers, materials processing, and frequency comb spectroscopy.
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49
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Chi Z, Chen H, Zhao Q, Weng YX. Ultrafast carrier and phonon dynamics in few-layer 2H-MoTe 2. J Chem Phys 2019; 151:114704. [PMID: 31542040 DOI: 10.1063/1.5115467] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
By using femtosecond pump-probe spectroscopy with broadband detection from near-infrared to midinfrared, the carrier and phonon dynamics in few-layer 2H-MoTe2 after ultrafast excitation have been investigated in detail. Immediately following the photoexcitation, an ultrafast relaxation of the generated hot carriers by releasing phonons is observed within hundreds of femtoseconds. The subsequent electron-hole recombination with a time constant of ∼1.5 ps is clearly identified and demonstrated to be mediated through a defect-assisted process. Furthermore, we confirm that the observed redshift of the exciton resonance energy on longer time scales arises from the ultrafast thermalization of the 2H-MoTe2 lattice caused by the transfer of electronic excitation to the phonon system. As a result, the thermalization dynamics of the lattice within 2 ps and the following cooling process of the phonon system on the 100 ps time scale are directly monitored.
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Affiliation(s)
- Zhen Chi
- Center for Quantum Technology Research, School of Physics, Beijing Institute of Technology, Beijing 100081, China
| | - Hailong Chen
- Beijing National Laboratory for Condensed Matter Physics, CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Qing Zhao
- Center for Quantum Technology Research, School of Physics, Beijing Institute of Technology, Beijing 100081, China
| | - Yu-Xiang Weng
- Beijing National Laboratory for Condensed Matter Physics, CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
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50
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Qi D, Han C, Rong X, Zhang XW, Chhowalla M, Wee ATS, Zhang W. Continuously Tuning Electronic Properties of Few-Layer Molybdenum Ditelluride with in Situ Aluminum Modification toward Ultrahigh Gain Complementary Inverters. ACS NANO 2019; 13:9464-9472. [PMID: 31328916 DOI: 10.1021/acsnano.9b04416] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Semiconducting molybdenum ditelluride (2H-MoTe2), a two-dimensional (2D) transition metal dichalcogenide, has attracted extensive research attention due to its favorable physical properties for future electronic devices, such as appropriate bandgap, ambipolar transport characteristic, and good chemical stability. The rational tuning of its electronic properties is a key point to achieve MoTe2-based complementary electronic and optoelectronic devices. Herein, we demonstrate the dynamic and effective control of the electronic properties of few-layer MoTe2, through the in situ surface modification with aluminum (Al) adatoms, with a view toward high-performance complementary inverter devices. MoTe2 is found to be significantly electron doped by Al, exhibiting a continuous transport transition from p-dominated ambipolar to n-type unipolar with enhanced electron mobility. Using a spatially controlled Al doping technique, both p- and n-channels are established on a single MoTe2 nanosheet, which gives complementary inverters with a record-high gain of ∼195, which stands out in the 2D family of materials due to the balanced p- and n-transport in Al-modified MoTe2. Our studies coupled with the tunable nature of in situ modification enable MoTe2 to be a promising candidate for high-performance complementary electronics.
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Affiliation(s)
- Dianyu Qi
- SZU-NUS Collaborative Innovation Center for Optoelectronic Science & Technology, International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education, College of Physics and Optoelectronic Engineering , Shenzhen University , Shenzhen 518060 , China
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117551 , Singapore
| | - Cheng Han
- SZU-NUS Collaborative Innovation Center for Optoelectronic Science & Technology, International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education, College of Physics and Optoelectronic Engineering , Shenzhen University , Shenzhen 518060 , China
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117551 , Singapore
| | - Ximing Rong
- Shenzhen Key Laboratory of Flexible Memory Materials and Devices, College of Electronic Science and Technology , Shenzhen University , Shenzhen 518060 , China
| | - Xiu-Wen Zhang
- Shenzhen Key Laboratory of Flexible Memory Materials and Devices, College of Electronic Science and Technology , Shenzhen University , Shenzhen 518060 , China
| | - Manish Chhowalla
- Department of Materials Science and Metallurgy , Cambridge University , 27 Charles Babbage Road , Cambridge , CB3 0FS , U.K
| | - Andrew T S Wee
- Department of Physics , National University of Singapore , 2 Science Drive 3 , Singapore 117551 , Singapore
- Centre for Advanced 2D Materials , National University of Singapore , Block S14, 6 Science Drive 2 , Singapore 117546 , Singapore
| | - Wenjing Zhang
- SZU-NUS Collaborative Innovation Center for Optoelectronic Science & Technology, International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education, College of Physics and Optoelectronic Engineering , Shenzhen University , Shenzhen 518060 , China
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