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Rosyadi AS, Lin YX, Peng YH, Ho CH. Axially-Polarized Excitonic Series and Anisotropic van der Waals Stacked Heterojunction in a Quasi-1D Layered Transition-Metal Trichalcogenide. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2406781. [PMID: 39099435 DOI: 10.1002/advs.202406781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2024] [Revised: 07/17/2024] [Indexed: 08/06/2024]
Abstract
Anisotropic optical 2D materials are crucial for achieving multiple-quanta functions within quantum materials, which enables the fabrication of axially polarized electronic and optoelectronic devices. In this work, multiple excitonic emissions owning polarization-sensitive orientations are clearly detected in a multilayered quasi-1D ZrS3 nanoribbon with respect to the nanostripe edge. Four excitons denoted as AS1, AS2, AS, and A2 with E ⊥ b polarized direction and one prominent A1 exciton with E || b polarized emission are simultaneously detected in the polarized micro-photoluminescence (µPL) measurement of 1.9-2.2 eV at 10 K. In contrast to light emission, polarized micro-thermoreflectance (µTR) measurements are performed to identify the polarization dependence and verify the excitons in the multilayered ZrS3 nanoribbon from the perspective of light absorption. At 10 K, a prominent and broadened peak on the lower-energy side, containing an indirect resonant emission (DI) observed by µPL and an indirect defect-bound exciton peak (AInd) observed by both µPL and µTR, is simultaneously detected, confirming the existence of a quasi-direct band edge in ZrS3. A van der Waals stacked p-GaSe/n-ZrS3 heterojunction solar cell is fabricated, which demonstrates a maximum axially-polarized conversion efficiency up to 0.412% as the E || b polarized light incident onto the device.
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Affiliation(s)
- Adzilah Shahna Rosyadi
- Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei, 106, Taiwan
| | - Ying-Xuan Lin
- Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei, 106, Taiwan
| | - Yu-Hung Peng
- Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei, 106, Taiwan
| | - Ching-Hwa Ho
- Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei, 106, Taiwan
- Taiwan Consortium of Emergent Crystalline Materials (TCECM), National Science and Technology Council, Taipei, 106, Taiwan
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2
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Xu J, Liu W, Jiang X, Huang K, Li P, Yu J, You Y, Wang Y, Zhang Y. Coherent potential approximation study of impurity effect on monolayer hexagonal boron phosphide. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:315002. [PMID: 38657640 DOI: 10.1088/1361-648x/ad42f1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Accepted: 04/24/2024] [Indexed: 04/26/2024]
Abstract
Impurity doping is a necessary technology for the application of semiconductor materials in microelectronic devices. The quantification of doping effects is crucial for controlling the transport properties of semiconductors. Here, taking two-dimensional (2D) hexagonal boron phosphide semiconductor as an example, we employ coherent potential approximation method to investigate the electronic properties of 2D semiconductor materials at low doping concentrations, which cannot be exploited with conventional density function theory. The results demonstrate that the positive or negative impurity potential in 2D semiconductors determines whether it is p-type or n-type doping, while the impurity potential strength decides whether it is shallow-level or deep-level doping. Impurity concentration has important impacts on not only the intensity but also the broadening of impurity peak in band gap. Importantly, we provide the operating temperature range of hexagonal boron phosphide as a semiconductor device under different impurity concentrations and impurity potentials. The methodology of this study can be applied to other 2D semiconductors, which is of great significance for quantitative research on the application of 2D semiconductors for electronic devices.
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Affiliation(s)
- Jinrong Xu
- Key Laboratory of Advanced Electronic Materials and Devices, School of Physics and Mathematics, Anhui Jianzhu University, Hefei 230601, People's Republic of China
| | - Wenjing Liu
- Key Laboratory of Advanced Electronic Materials and Devices, School of Physics and Mathematics, Anhui Jianzhu University, Hefei 230601, People's Republic of China
| | - Xiucai Jiang
- Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and Engineering, Tongji University, Shanghai 200092, People's Republic of China
| | - Kai Huang
- Key Laboratory of Advanced Electronic Materials and Devices, School of Physics and Mathematics, Anhui Jianzhu University, Hefei 230601, People's Republic of China
| | - Ping Li
- Key Laboratory of Advanced Electronic Materials and Devices, School of Physics and Mathematics, Anhui Jianzhu University, Hefei 230601, People's Republic of China
| | - Jiangying Yu
- Key Laboratory of Advanced Electronic Materials and Devices, School of Physics and Mathematics, Anhui Jianzhu University, Hefei 230601, People's Republic of China
| | - Yuwei You
- Key Laboratory of Advanced Electronic Materials and Devices, School of Physics and Mathematics, Anhui Jianzhu University, Hefei 230601, People's Republic of China
| | - Ying Wang
- Key Laboratory of Advanced Electronic Materials and Devices, School of Physics and Mathematics, Anhui Jianzhu University, Hefei 230601, People's Republic of China
| | - Yuzhong Zhang
- Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and Engineering, Tongji University, Shanghai 200092, People's Republic of China
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3
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Bangolla HK, Yusuf Fakhri M, Lin CH, Cheng CM, Lu YH, Fu TY, Selvarasu P, Ulaganathan RK, Sankar R, Chen RS. Electrical and optoelectronic anisotropy and surface electron accumulation in ReS 2 nanostructures. NANOSCALE 2023. [PMID: 38047470 DOI: 10.1039/d3nr04830f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Two interesting electronic transport properties including in-plane anisotropy and nonhomogeneous carrier distribution were observed in ReS2 nanoflakes. The electrical conductivity defined by the current parallel to the b-axis (‖b) is 32 times higher than that perpendicular to the b-axis (⊥b). Similar anisotropy was also observed in optoelectronic properties in which the ratio of responsivity ‖b to ⊥b reaches 20. In addition, conductivity and thermal activation energy with substantial thickness dependence were observed, which indicates a surface-dominant 2D transport in ReS2 nanoflakes. The presence of surface electron accumulation (SEA) in ReS2 has been confirmed by angle-resolved photoemission spectroscopy and scanning tunneling spectroscopy. The electron concentration (∼1019 cm-3) at the surface is over three orders of magnitude higher than that of the bulks. Sulfur vacancies which are sensitive to air molecules are suggested to be the major factor resulting in SEA and high conductivity in ReS2 nanostructures.
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Affiliation(s)
- Hemanth Kumar Bangolla
- Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 10607, Taiwan.
| | - Muhammad Yusuf Fakhri
- Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 10607, Taiwan.
| | - Ching-Hsuan Lin
- Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 10607, Taiwan.
| | - Cheng-Maw Cheng
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
- Department of Physics, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
- Taiwan Consortium of Emergent Crystalline Materials, National Science and Technology Council, Taipei 10601, Taiwan
| | - Yi-Hung Lu
- Department of Physics, National Taiwan Normal University, Taipei 11677, Taiwan
| | - Tsu-Yi Fu
- Department of Physics, National Taiwan Normal University, Taipei 11677, Taiwan
| | - Pushpa Selvarasu
- Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 10607, Taiwan.
| | | | - Raman Sankar
- Institute of Physics, Academia Sinica, Taipei 115201, Taiwan
| | - Ruei-San Chen
- Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 10607, Taiwan.
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4
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Ilango PR, Savariraj AD, Huang H, Li L, Hu G, Wang H, Hou X, Kim BC, Ramakrishna S, Peng S. Electrospun Flexible Nanofibres for Batteries: Design and Application. ELECTROCHEM ENERGY R 2023. [DOI: 10.1007/s41918-022-00148-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
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5
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Kim D, Pandey J, Jeong J, Cho W, Lee S, Cho S, Yang H. Phase Engineering of 2D Materials. Chem Rev 2023; 123:11230-11268. [PMID: 37589590 DOI: 10.1021/acs.chemrev.3c00132] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/18/2023]
Abstract
Polymorphic 2D materials allow structural and electronic phase engineering, which can be used to realize energy-efficient, cost-effective, and scalable device applications. The phase engineering covers not only conventional structural and metal-insulator transitions but also magnetic states, strongly correlated band structures, and topological phases in rich 2D materials. The methods used for the local phase engineering of 2D materials include various optical, geometrical, and chemical processes as well as traditional thermodynamic approaches. In this Review, we survey the precise manipulation of local phases and phase patterning of 2D materials, particularly with ideal and versatile phase interfaces for electronic and energy device applications. Polymorphic 2D materials and diverse quantum materials with their layered, vertical, and lateral geometries are discussed with an emphasis on the role and use of their phase interfaces. Various phase interfaces have demonstrated superior and unique performance in electronic and energy devices. The phase patterning leads to novel homo- and heterojunction structures of 2D materials with low-dimensional phase boundaries, which highlights their potential for technological breakthroughs in future electronic, quantum, and energy devices. Accordingly, we encourage researchers to investigate and exploit phase patterning in emerging 2D materials.
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Affiliation(s)
- Dohyun Kim
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Juhi Pandey
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Juyeong Jeong
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Woohyun Cho
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Seungyeon Lee
- Division of Chemical Engineering and Materials Science, Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul 03760, Korea
| | - Suyeon Cho
- Division of Chemical Engineering and Materials Science, Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul 03760, Korea
| | - Heejun Yang
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
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6
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Ding D, Qu Z, Han X, Han C, Zhuang Q, Yu XL, Niu R, Wang Z, Li Z, Gan Z, Wu J, Lu J. Multivalley Superconductivity in Monolayer Transition Metal Dichalcogenides. NANO LETTERS 2022; 22:7919-7926. [PMID: 36173038 DOI: 10.1021/acs.nanolett.2c02947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
In transition metal dichalcogenides (TMDs), Ising superconductivity with an antisymmetric spin texture on the Fermi surface has attracted wide interest due to the exotic pairing and topological properties. However, it is not clear whether the Q valley with a giant spin splitting is involved in the superconductivity of heavily doped semiconducting 2H-TMDs. Here by taking advantage of a high-quality monolayer WS2 on hexagonal boron nitride flakes, we report an ionic-gating induced superconducting dome with a record high critical temperature of ∼6 K, accompanied by an emergent nonlinear Hall effect. The nonlinearity indicates the development of an additional high-mobility channel, which (corroborated by first principle calculations) can be ascribed to the population of Q valleys. Thus, multivalley population at K and Q is suggested to be a prerequisite for developing superconductivity. The involvement of Q valleys also provides insights to the spin textured Fermi surface of Ising superconductivity in the large family of transition metal dichalcogenides.
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Affiliation(s)
- Dongdong Ding
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Zhuangzhuang Qu
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Xiangyan Han
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Chunrui Han
- Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Quan Zhuang
- Shenzhen Institute for Quantum Science and Engineering (SIQSE), Southern University of Science and Technology, Shenzhen 518055, China
- Inner Mongolia Key Laboratory of Carbon Nanomaterials, Nano Innovation Institute (NII), Inner Mongolia Minzu University, Tongliao 028000, China
| | - Xiang-Long Yu
- Shenzhen Institute for Quantum Science and Engineering (SIQSE), Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
| | - Ruirui Niu
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Zhiyu Wang
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Zhuoxian Li
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Zizhao Gan
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Jiansheng Wu
- Shenzhen Institute for Quantum Science and Engineering (SIQSE), Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
| | - Jianming Lu
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
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7
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Piatti E, Guglielmero L, Tofani G, Mezzetta A, Guazzelli L, D'Andrea F, Roddaro S, Pomelli CS. Ionic liquids for electrochemical applications: Correlation between molecular structure and electrochemical stability window. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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8
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Enhanced interfacial effect between CdS and ReS2 on boosted hydrogen evolution performance via phase structure engineering. J SOLID STATE CHEM 2022. [DOI: 10.1016/j.jssc.2022.123238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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9
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Liu W, Wang P, Ao Y, Chen J, Gao X, Jia B, Ma T. Directing Charge Transfer in a Chemical-Bonded BaTiO 3 @ReS 2 Schottky Heterojunction for Piezoelectric Enhanced Photocatalysis. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2202508. [PMID: 35560713 DOI: 10.1002/adma.202202508] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 04/30/2022] [Indexed: 06/15/2023]
Abstract
The piezo-assisted photocatalysis system, which can utilize solar energy and mechanical energy simulteneously, is promising but still challenging in the environmental remediation field. In this work, a novel metal-semiconductor BaTiO3 @ReS2 Schottky heterostructure is designed and it shows high-efficiency on piezo-assisted photocatalytic molecular oxygen activation. By combining experiment and calculation results, the distorted metal-phase ReS2 nanosheets are found to be closely anchored on the surface of the BaTiO3 nanorods, through interfacial ReO covalent bonds. The Schottky heterostructure not only forms electron-transfer channels but also exhibits enhanced oxygen activation capacity, which are helpful to produce more superoxide radicals. The polarization field induced by the piezoelectric BaTiO3 can lower the Schottky barrier and thus reduce the transfer resistance of photogenerated electrons directing to the ReS2 . As a result of the synergy effect between the two components, the BaTiO3 @ReS2 exhibits untrahigh activity for degradation of pollutants with an apparent rate constant of 0.133 min-1 for piezo-assisted photocatalysis, which is 16.6 and 2.44 times as that of piezocatalysis and photocatalysis, respectively. This performance is higher than most reported BaTiO3 -based piezo-assisted photocatalysis systems. This work paves the way for the design of high-efficiency piezo-assisted photocatalytic materials for environmental remediation through using green energies in nature.
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Affiliation(s)
- Wei Liu
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, No. 1, Xikang road, Nanjing, 210098, China
| | - Peifang Wang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, No. 1, Xikang road, Nanjing, 210098, China
| | - Yanhui Ao
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, No. 1, Xikang road, Nanjing, 210098, China
| | - Juan Chen
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, No. 1, Xikang road, Nanjing, 210098, China
| | - Xin Gao
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, No. 1, Xikang road, Nanjing, 210098, China
| | - Baohua Jia
- School of Science, RMIT University, Melbourne, VIC, 3000, Australia
| | - Tianyi Ma
- School of Science, RMIT University, Melbourne, VIC, 3000, Australia
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10
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Piatti E, Montagna Bozzone J, Daghero D. Anomalous Metallic Phase in Molybdenum Disulphide Induced via Gate-Driven Organic Ion Intercalation. NANOMATERIALS 2022; 12:nano12111842. [PMID: 35683696 PMCID: PMC9181884 DOI: 10.3390/nano12111842] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 05/24/2022] [Accepted: 05/25/2022] [Indexed: 11/16/2022]
Abstract
Transition metal dichalcogenides exhibit rich phase diagrams dominated by the interplay of superconductivity and charge density waves, which often result in anomalies in the electric transport properties. Here, we employ the ionic gating technique to realize a tunable, non-volatile organic ion intercalation in bulk single crystals of molybdenum disulphide (MoS2). We demonstrate that this gate-driven organic ion intercalation induces a strong electron doping in the system without changing the pristine 2H crystal symmetry and triggers the emergence of a re-entrant insulator-to-metal transition. We show that the gate-induced metallic state exhibits clear anomalies in the temperature dependence of the resistivity with a natural explanation as signatures of the development of a charge-density wave phase which was previously observed in alkali-intercalated MoS2. The relatively large temperature at which the anomalies are observed (∼150 K), combined with the absence of any sign of doping-induced superconductivity down to ∼3 K, suggests that the two phases might be competing with each other to determine the electronic ground state of electron-doped MoS2.
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11
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He T, Frisbie CD. Sub-Band Filling, Mott-like Transitions, and Ion Size Effects in C 60 Single Crystal Electric Double Layer Transistors. ACS NANO 2022; 16:4823-4830. [PMID: 35243860 DOI: 10.1021/acsnano.2c00222] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Electric double layer transistors (EDLTs) based on C60 single crystals and ionic liquid gates display pronounced peaks in sheet conductance versus gate-induced charge. Sheet conductance is maximized at electron densities near 0.5 e/C60 and is suppressed near 1 e/C60. The conductance suppression depends markedly on the choice of ionic liquid cation, with small cations favoring activated transport and essentially a complete shutdown of conductance at ∼1 e/C60 and larger cations favoring band-like transport, higher overall conductances at all charge densities up to 1.7 e/C60, and weaker suppression at 1 e/C60. Displacement current measurements on C60 EDLTs with small cations show clear evidence of sub-band filling at 1 e/C60, which correlates very well with the minimum in the C60 sheet conductance. Overall, the data suggest a significant Mott-Hubbard-like energy gap opens up in the surface density of states for C60 crystals gated with small cations. The causes of this energy gap may include both electron-electron repulsion and electron-cation attraction at the crystal/ionic liquid interface. The energy gap suppresses the insulator-to-metal transition in C60 EDLTs, but it can be manipulated by choice of electrolyte.
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Affiliation(s)
- Tao He
- State Key Laboratory of Crystal Materials, Shandong University, 250100, Jinan, Shandong, People's Republic of China
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - C Daniel Frisbie
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, United States
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12
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Quantum interference directed chiral raman scattering in two-dimensional enantiomers. Nat Commun 2022; 13:1254. [PMID: 35273159 PMCID: PMC8913836 DOI: 10.1038/s41467-022-28877-6] [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: 05/30/2021] [Accepted: 02/16/2022] [Indexed: 12/04/2022] Open
Abstract
Raman scattering spectroscopy has been a necessary and accurate tool not only for characterizing lattice structure, but also for probing electron-photon and electron-phonon interactions. In the quantum picture, electrons at ground states can be excited to intermediate energy levels by photons at different k-points in the Brillouin zone, then couple to phonons and emit photons with changed energies. The elementary Raman processes via all possible pathways can interfere with each other, giving rise to intriguing scattering effects. Here we report that quantum interference can lead to significant chiral Raman response in monolayer transitional metal dichalcogenide with triclinic symmetry. Large circular intensity difference observed for monolayer rhenium dichalcogenide originates from inter-k interference of Raman scattering excited by circularly polarized light with opposite helicities. Our results reveal chiral Raman spectra as a new manifestation of quantum interference in Raman scattering process, and may inspire induction of chiral optical response in other materials. Quantum interference among elementary Raman processes has only been observed in few materials under specific excitation configurations. Here, the authors show that quantum interference can lead to significant chiral Raman response in a monolayer material of transitional metal dichalcogenide with triclinic symmetry.
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13
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Wang L, Xiang D, Gao K, Wang J, Wu K. Colloidal n-Doped CdSe and CdSe/ZnS Nanoplatelets. J Phys Chem Lett 2021; 12:11259-11266. [PMID: 34766755 DOI: 10.1021/acs.jpclett.1c02856] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Colloidal semiconductor nanoplatelets (NPLs) are chemical versions of well-studied quantum wells (QWs). For QWs, gating and carrier doping are standard tools to manipulate their optical, electric, or magnetic properties. It would be highly desirable to use pure chemical methods to dope extra charge carriers into free-standing colloidal NPLs to achieve a similar level of manipulation. Here we report colloidal n-doped CdSe and CdSe/ZnS NPLs achieved through a photochemical doping method. The extra electrons doped into the conduction band edges are evidenced by exciton absorption bleaches recoverable through dedoping and the appearance of new intersub-band transitions in the near-infrared. A high surface ligand coverage is the key to successful doping; otherwise, the doped electrons can be depleted likely by unpassivated surface cations. Large trion binding energies of 20-30 meV are found for the n-doped CdSe NPLs, which, in contrast, are reduced by 1 order of magnitude in CdSe/ZnS core/shell NPLs due to dielectric screening. Furthermore, we identify a long-lived negative trion with a lifetime of 1.5-1.6 ns that is likely dominated by radiative recombination.
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Affiliation(s)
- Lifeng Wang
- State Key Laboratory of Molecular Reaction Dynamics and Dynamics Research Center for Energy and Environmental Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Dongmei Xiang
- State Key Laboratory of Molecular Reaction Dynamics and Dynamics Research Center for Energy and Environmental Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China
| | - Kaimin Gao
- State Key Laboratory of Molecular Reaction Dynamics and Dynamics Research Center for Energy and Environmental Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Junhui Wang
- State Key Laboratory of Molecular Reaction Dynamics and Dynamics Research Center for Energy and Environmental Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kaifeng Wu
- State Key Laboratory of Molecular Reaction Dynamics and Dynamics Research Center for Energy and Environmental Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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14
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Kasuya N, Tsurumi J, Okamoto T, Watanabe S, Takeya J. Two-dimensional hole gas in organic semiconductors. NATURE MATERIALS 2021; 20:1401-1406. [PMID: 34489565 DOI: 10.1038/s41563-021-01074-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 07/05/2021] [Indexed: 05/06/2023]
Abstract
A highly conductive metallic gas that is quantum mechanically confined at a solid-state interface is an ideal platform to explore non-trivial electronic states that are otherwise inaccessible in bulk materials. Although two-dimensional electron gases have been realized in conventional semiconductor interfaces, examples of two-dimensional hole gases, the counterpart to the two-dimensional electron gas, are still limited. Here we report the observation of a two-dimensional hole gas in solution-processed organic semiconductors in conjunction with an electric double layer using ionic liquids. A molecularly flat single crystal of high-mobility organic semiconductors serves as a defect-free interface that facilitates two-dimensional confinement of high-density holes. A remarkably low sheet resistance of 6 kΩ and high hole-gas density of 1014 cm-2 result in a metal-insulator transition at ambient pressure. The measured degenerate holes in the organic semiconductors provide an opportunity to tailor low-dimensional electronic states using molecularly engineered heterointerfaces.
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Affiliation(s)
- Naotaka Kasuya
- Material Innovation Research Center (MIRC) and Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation laboratory (OPERAND-OIL), National Institute of Advanced Industrial Science and Technology (AIST), Kashiwa, Japan
| | - Junto Tsurumi
- Material Innovation Research Center (MIRC) and Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
- International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), Tsukuba, Japan
| | - Toshihiro Okamoto
- Material Innovation Research Center (MIRC) and Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation laboratory (OPERAND-OIL), National Institute of Advanced Industrial Science and Technology (AIST), Kashiwa, Japan
- Precursory Research For Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), Kawaguchi, Japan
| | - Shun Watanabe
- Material Innovation Research Center (MIRC) and Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan.
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation laboratory (OPERAND-OIL), National Institute of Advanced Industrial Science and Technology (AIST), Kashiwa, Japan.
| | - Jun Takeya
- Material Innovation Research Center (MIRC) and Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan.
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation laboratory (OPERAND-OIL), National Institute of Advanced Industrial Science and Technology (AIST), Kashiwa, Japan.
- International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), Tsukuba, Japan.
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15
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Ghimire G, Dhakal KP, Choi W, Esthete YA, Kim SJ, Tran TT, Lee H, Yang H, Duong DL, Kim YM, Kim J. Doping-Mediated Lattice Engineering of Monolayer ReS 2 for Modulating In-Plane Anisotropy of Optical and Transport Properties. ACS NANO 2021; 15:13770-13780. [PMID: 34296605 DOI: 10.1021/acsnano.1c05316] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
ReS2 exhibits strong anisotropic optical and electrical responses originating from the asymmetric lattice. Here, we show that the anisotropy of monolayer (1L) ReS2 in optical scattering and electrical transport can be practically erased by lattice engineering via lithium (Li) treatment. Scanning transmission electron microscopy revealed that significant strain is induced in the lattice of Li-treated 1L-ReS2, due to high-density electron doping and the resultant formation of continuous tiling of nanodomains with randomly rotating orientations of 60°, which produced a nearly isotropic response of polarized Raman scattering and absorption of Li-treated 1L-ReS2. With Li treatment, the in-plane conductance of 1L-ReS2 increased by an order of magnitude, and its angle dependence became negligible. Our result that the asymmetric phase was converted into the isotropic phase by electron injection could significantly expand the optoelectronic applications of polymorphic two-dimensional transition metal dichalcogenides.
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Affiliation(s)
- Ganesh Ghimire
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Krishna P Dhakal
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Wooseon Choi
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Yonas Assefa Esthete
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Seon Je Kim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Trang Thu Tran
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Hyoyoung Lee
- Center for Integrated Nanostructure Physics, Institute for Basic Science, Suwon 16419, Republic of Korea
- Department of Chemistry, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Heejun Yang
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Dinh Loc Duong
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
- Center for Integrated Nanostructure Physics, Institute for Basic Science, Suwon 16419, Republic of Korea
| | - Young-Min Kim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
- Center for Integrated Nanostructure Physics, Institute for Basic Science, Suwon 16419, Republic of Korea
| | - Jeongyong Kim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
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16
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Abstract
Abstract
Ionic gating is a very popular tool to investigate and control the electric charge transport and electronic ground state in a wide variety of different materials. This is due to its capability to induce large modulations of the surface charge density by means of the electric-double-layer field-effect transistor (EDL-FET) architecture, and has been proven to be capable of tuning even the properties of metallic systems. In this short review, I summarize the main results which have been achieved so far in controlling the superconducting (SC) properties of thin films of conventional metallic superconductors by means of the ionic gating technique. I discuss how the gate-induced charge doping, despite being confined to a thin surface layer by electrostatic screening, results in a long-range ‘bulk’ modulation of the SC properties by the coherent nature of the SC condensate, as evidenced by the observation of suppressions in the critical temperature of films much thicker than the electrostatic screening length, and by the pronounced thickness-dependence of their magnitude. I review how this behavior can be modelled in terms of proximity effect between the charge-doped surface layer and the unperturbed bulk with different degrees of approximation, and how first-principles calculations have been employed to determine the origin of an anomalous increase in the electrostatic screening length at ultrahigh electric fields, thus fully confirming the validity of the proximity effect model. Finally, I discuss a general framework—based on the combination of ab-initio Density Functional Theory and the Migdal-Eliashberg theory of superconductivity—by which the properties of any gated thin film of a conventional metallic superconductor can be determined purely from first principles.
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17
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Das S, Prasad S, Chakraborty B, Jariwala B, Shradha S, Muthu DVS, Bhattacharya A, Waghmare UV, Sood AK. Doping controlled Fano resonance in bilayer 1T'-ReS 2: Raman experiments and first-principles theoretical analysis. NANOSCALE 2021; 13:1248-1256. [PMID: 33404576 DOI: 10.1039/d0nr06583h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
In the bilayer ReS2 channel of a field-effect transistor (FET), we demonstrate using Raman spectroscopy that electron doping (n) results in softening of frequency and broadening of linewidth for the in-plane vibrational modes, leaving the out-of-plane vibrational modes unaffected. The largest change is observed for the in-plane Raman mode at ∼151 cm-1, which also shows doping induced Fano resonance with the Fano parameter 1/q = -0.17 at a doping concentration of ∼3.7 × 1013 cm-2. A quantitative understanding of our results is provided by first-principles density functional theory (DFT), showing that the electron-phonon coupling (EPC) of in-plane modes is stronger than that of out-of-plane modes, and its variation with doping is independent of the layer stacking. The origin of large EPC is traced to 1T to 1T' structural phase transition of ReS2 involving in-plane displacement of atoms whose instability is driven by the nested Fermi surface of the 1T structure. Results are compared with those of the isostructural trilayer ReSe2.
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Affiliation(s)
- Subhadip Das
- Department of Physics, Indian Institute of Science, Bangalore 560012, India.
| | - Suchitra Prasad
- Theoretical Sciences Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | | | - Bhakti Jariwala
- Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Mumbai 400005, India
| | - Sai Shradha
- Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Mumbai 400005, India
| | - D V S Muthu
- Department of Physics, Indian Institute of Science, Bangalore 560012, India.
| | - Arnab Bhattacharya
- Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Mumbai 400005, 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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18
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Li X, Chen C, Yang Y, Lei Z, Xu H. 2D Re-Based Transition Metal Chalcogenides: Progress, Challenges, and Opportunities. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:2002320. [PMID: 33304762 PMCID: PMC7709994 DOI: 10.1002/advs.202002320] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 08/22/2020] [Indexed: 05/16/2023]
Abstract
The rise of 2D transition-metal dichalcogenides (TMDs) materials has enormous implications for the scientific community and beyond. Among TMDs, ReX2 (X = S, Se) has attracted significant interest regarding its unusual 1T' structure and extraordinary properties in various fields during the past 7 years. For instance, ReX2 possesses large bandgaps (ReSe2: 1.3 eV, ReS2: 1.6 eV), distinctive interlayer decoupling, and strong anisotropic properties, which endow more degree of freedom for constructing novel optoelectronic, logic circuit, and sensor devices. Moreover, facile ion intercalation, abundant active sites, together with stable 1T' structure enable them great perspective to fabricate high-performance catalysts and advanced energy storage devices. In this review, the structural features, fundamental physicochemical properties, as well as all existing applications of Re-based TMDs materials are comprehensively introduced. Especially, the emerging synthesis strategies are critically analyzed and pay particular attention is paid to its growth mechanism with probing the assembly process of domain architectures. Finally, current challenges and future opportunities regarding the controlled preparation methods, property, and application exploration of Re-based TMDs are discussed.
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Affiliation(s)
- Xiaobo Li
- Key Laboratory of Applied Surface and Colloid ChemistryMinistry of EducationShaanxi Key Laboratory for Advanced Energy DevicesSchool of Materials Science and EngineeringShaanxi Normal UniversityXi'an710119P. R. China
| | - Chao Chen
- Key Laboratory of Applied Surface and Colloid ChemistryMinistry of EducationShaanxi Key Laboratory for Advanced Energy DevicesSchool of Materials Science and EngineeringShaanxi Normal UniversityXi'an710119P. R. China
| | - Yang Yang
- Key Laboratory of Applied Surface and Colloid ChemistryMinistry of EducationShaanxi Key Laboratory for Advanced Energy DevicesSchool of Materials Science and EngineeringShaanxi Normal UniversityXi'an710119P. R. China
| | - Zhibin Lei
- Key Laboratory of Applied Surface and Colloid ChemistryMinistry of EducationShaanxi Key Laboratory for Advanced Energy DevicesSchool of Materials Science and EngineeringShaanxi Normal UniversityXi'an710119P. R. China
| | - Hua Xu
- Key Laboratory of Applied Surface and Colloid ChemistryMinistry of EducationShaanxi Key Laboratory for Advanced Energy DevicesSchool of Materials Science and EngineeringShaanxi Normal UniversityXi'an710119P. R. China
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19
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Kwon IS, Kwak IH, Ju S, Kang S, Han S, Park YC, Park J, Park J. Adatom Doping of Transition Metals in ReSe 2 Nanosheets for Enhanced Electrocatalytic Hydrogen Evolution Reaction. ACS NANO 2020; 14:12184-12194. [PMID: 32852936 DOI: 10.1021/acsnano.0c05874] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Two-dimensional Re dichalcogenide nanostructures are promising electrocatalysts for the hydrogen evolution reaction (HER). Herein, we report the adatom doping of various transition metals (TM = Mn, Fe, Co, Ni, and Cu) in ReSe2 nanosheets synthesized using a solvothermal reaction. As the atomic number of TM increases from Mn to Cu, the adatoms on Re sites become more favored over the substitution. In the case of Ni, the fraction of adatoms reaches 90%. Ni doping resulted in the most effective enhancement in the HER catalytic performance, which was characterized by overpotentials of 82 and 109 mV at 10 mA cm-2 in 0.5 M H2SO4 and 1 M KOH, respectively, and the Tafel slopes of 54 and 81 mV dec-1. First-principles calculations predicted that the adatom doping structures (TMs on Re sites) have higher catalytic activity compared with the substitution ones. The adsorbed H atoms formed a midgap hybridized state via direct bonding with the orbitals of TM adatom. The present work provides a deeper understanding into how TM doping can provide the catalytically active sites in these ReSe2 nanosheets.
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Affiliation(s)
- Ik Seon Kwon
- Department of Advanced Materials Chemistry, Korea University, Sejong 339-700, Republic of Korea
| | - In Hye Kwak
- Department of Advanced Materials Chemistry, Korea University, Sejong 339-700, Republic of Korea
| | - Suyeon Ju
- Department of Materials Science and Engineering and Research Institute of Advanced Materials, Seoul National University, Seoul 08826, Korea
| | - Sungwoo Kang
- Department of Materials Science and Engineering and Research Institute of Advanced Materials, Seoul National University, Seoul 08826, Korea
| | - Seungwu Han
- Department of Materials Science and Engineering and Research Institute of Advanced Materials, Seoul National University, Seoul 08826, Korea
| | - Yun Chang Park
- Measurement and Analysis Division, National Nanofab Center (NNFC), Daejeon 305-806, Republic of Korea
| | - Jucheol Park
- Gyeongbuk Science & Technology Promotion Center, Gumi Electronics & Information Technology Research Institute, Gumi, 39171, Republic of Korea
| | - Jeunghee Park
- Department of Advanced Materials Chemistry, Korea University, Sejong 339-700, Republic of Korea
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20
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Site-specific electrical contacts with the two-dimensional materials. Nat Commun 2020; 11:3982. [PMID: 32770067 PMCID: PMC7414847 DOI: 10.1038/s41467-020-17784-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 07/15/2020] [Indexed: 11/18/2022] Open
Abstract
Electrical contact is an essential issue for all devices. Although the contacts of the emergent two-dimensional materials have been extensively investigated, it is still challenging to produce excellent contacts. The face and edge type contacts have been applied previously, however a comparative study on the site-specific contact performances is lacking. Here we report an in situ transmission electron microscopy study on the contact properties with a series of 2D materials. By manipulating the contact configurations in real time, it is confirmed that, for 2D semiconductors the vdW type face contacts exhibit superior conductivity compared with the non-vdW type contacts. The direct quantum tunneling across the vdW bonded interfaces are virtually more favorable than the Fowler–Nordheim tunneling across chemically bonded interfaces for contacts. Meanwhile, remarkable area, thickness, geometry, and defect site dependences are revealed. Our work sheds light on the significance of contact engineering for 2D materials in future applications. Here, the authors use in situ transmission electron microscopy to measure the interface properties of electrical contacts with MoS2, ReS2, and graphene, and find that direct quantum tunnelling across van-der-Waals-bonded interfaces is more favourable than Fowler–Nordheim tunnelling across chemically bonded interfaces.
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21
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Ho CH. Ga 2Se 3 Defect Semiconductors: The Study of Direct Band Edge and Optical Properties. ACS OMEGA 2020; 5:18527-18534. [PMID: 32743231 PMCID: PMC7392520 DOI: 10.1021/acsomega.0c02623] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 07/06/2020] [Indexed: 06/11/2023]
Abstract
Direct band edge is a crucial factor for a functional chalcogenide to be applied in luminescence devices, photodetectors, and solar-energy devices. In this work, the room-temperature band-edge emission of III-VI Ga2Se3 has been first observed by micro-photoluminescence (μPL) measurement. The emission peak is at 1.85 eV, which matches well with the band-edge transition that is measured by micro-thermoreflectance (μTR) and micro-transmittance (μTransmittance) for verification of the direct band edge of Ga2Se3. The temperature-dependent μTR spectra of Ga2Se3 show a general semiconductor behavior with its temperature-energy shift following Varshni-type variation. With the well-evident direct band edge, the peak responsivities of photovoltaic response (∼6.2 mV/μW) and photocurrent (∼2.25 μA/μW at f = 30 Hz) of defect zincblende Ga2Se3 can be, respectively, detected at ∼2.22 and ∼1.92 eV from a Cu/Ga2Se3 Schottky solar cell and a Ga2Se3 photoconductor. On the basis of experimental analysis, the optical band edge and photoresponsivity properties of a III-VI Ga2Se3 defect semiconductor are thus realized.
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Affiliation(s)
- Ching-Hwa Ho
- Graduate Institute of Applied
Science and Technology, National Taiwan
University of Science and Technology, Taipei 106, Taiwan
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22
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Chen R, Ao Y, Wang C, Wang P. The surface engineering of ReS 2 with cobalt for efficient performance in hydrogen evolution under both acid and alkaline conditions. Chem Commun (Camb) 2020; 56:8472-8475. [PMID: 32588840 DOI: 10.1039/d0cc01300e] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Cobalt-modified rhenium disulfide nanosheets rich in defects, obtained by following an ingenious atom substitution strategy, exhibited boosted HER performance. The 2%-Co doped ReS2 sample was highly efficient in both acid electrolyte (149 mV) and alkaline electrolyte (240 mV), achieving a current density of 10 mA cm-2 as well as superior long-term durability.
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Affiliation(s)
- Ran Chen
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China.
| | - Yanhui Ao
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China.
| | - Chao Wang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China.
| | - Peifang Wang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China.
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23
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Optical and Thermoelectric Properties of Surface-Oxidation Sensitive Layered Zirconium Dichalcogenides ZrS2−xSex (x = 0, 1, 2) Crystals Grown by Chemical Vapor Transport. CRYSTALS 2020. [DOI: 10.3390/cryst10040327] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In this work, structure, optical, and thermoelectric properties of layered ZrS2−xSex single crystals with selenium composition of x = 0, 1, and 2 were examined. Single crystals of zirconium dichalcogenides layer compounds were grown by chemical vapor transport method using I2 as the transport agent. X-ray diffraction (XRD) and high-resolution transmission electron microscope (HRTEM) results indicated that ZrS2−xSex (x = 0, 1, and 2) were crystalized in hexagonal CdI2 structure with one-layer trigonal (1T) stacking type. X-ray photoelectron and energy dispersive X-ray measurements revealed oxidation sensitive behavior of the chalcogenides series. Transmittance and optical absorption showed an indirect optical gap of about 1.78 eV, 1.32 eV, and 1.12 eV for the ZrS2−xSex with x = 0, 1, and 2, respectively. From the result of thermoelectric experiment, ZrSe2 owns the highest figure-of merit (ZT) of ~0.085 among the surface-oxidized ZrS2−xSex series layer crystals at 300 K. The ZT values of the ZrS2−xSex (x = 0, 1, and 2) series also reveal increase with the increase of Se content owing to the increase of carrier concentration and mobility in the highly Se-incorporated zirconium dichalcogenides with surface states.
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24
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Ho CH, Chiou MC, Herninda TM. Nanowire Grid Polarization and Polarized Excitonic Emission Observed in Multilayer GaTe. J Phys Chem Lett 2020; 11:608-617. [PMID: 31905289 DOI: 10.1021/acs.jpclett.9b03569] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In this study, near-infrared (NIR) x-polarized (P-state) light is created from the transmission ray of monoclinic multilayer GaTe near the band edge. The P-state transmittance photons are produced via the transmission light of a ribbonlike multilayer GaTe with a plurality of nanowire grids being parallel and constructed along the y direction (b axis) from 1.56 to 1.62 eV. At 300 K, a P-state excitonic emission at 1.652 eV can be clearly detected in polarized microphotoluminescence (μPL) measurement. The free-exciton extinction energy and recombination lifetime of the band-edge exciton are evaluated and determined to be ΔE = 32 ± 4 meV and τ ≈ 0.032 ns, respectively, for the multilayer GaTe. Polarized microthermoreflectance (μTR) measurement also verifies that the x-polarized transition is allowed while y-polarized (S-state) transition is forbidden in the multilayer GaTe. An asymmetric p-to-p transition along the x polarization is thus inferred to comprise the band edge of multilayer GaTe to form in-plane optical anisotropy.
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Affiliation(s)
- Ching-Hwa Ho
- Graduate Institute of Applied Science and Technology , National Taiwan University of Science and Technology , Taipei 106 , Taiwan
| | - Mei-Chan Chiou
- Graduate Institute of Applied Science and Technology , National Taiwan University of Science and Technology , Taipei 106 , Taiwan
| | - Thalita Maysha Herninda
- Graduate Institute of Applied Science and Technology , National Taiwan University of Science and Technology , Taipei 106 , Taiwan
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25
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Dhakal KP, Ghimire G, Chung K, Duong DL, Kim SW, Kim J. Probing Multiphased Transition in Bulk MoS 2 by Direct Electron Injection. ACS NANO 2019; 13:14437-14446. [PMID: 31756072 DOI: 10.1021/acsnano.9b08037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Structural phase transitions in layered two-dimensional (2D) materials are of significant interest owing to their ability to exist in multiple metastable states with distinctive properties. However, phase transition in bulk MoS2 by nondestructive electron infusion has not yet been realized. In this study, we report the 2H to 1T' phase transition and in-between intermediates in bulk MoS2 using MoS2/[Ca2N]+·e- heterostructures, in which kinetic free electrons were directly injected into MoS2. We observed various phases in MoS2 ranging from heavily doped 2H to a distorted lattice state and then on to a complete 1T' state. Snapshots of the multiphase transition were captured by extraordinary Raman shift and bandgap reduction and were further elucidated by theoretical calculations. We also observed a weakening in interlayer coupling in the vicinity of the metallic regime, which led to an unusually strong photoluminescence emission, suggesting light-efficient bulk MoS2. Our results thus suggest the optoelectronic applications that can fully utilize the multiphase transition of bulk 2D materials.
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Affiliation(s)
- Krishna P Dhakal
- Department of Energy Science , Sungkyunkwan University , Suwon 16419 , Republic of Korea
| | - Ganesh Ghimire
- Department of Energy Science , Sungkyunkwan University , Suwon 16419 , Republic of Korea
| | - Kyungwha Chung
- Department of Energy Science , Sungkyunkwan University , Suwon 16419 , Republic of Korea
| | - Dinh Loc Duong
- Department of Energy Science , Sungkyunkwan University , Suwon 16419 , Republic of Korea
- Center for Integrated Nanostructure Physics , Institute for Basic Science , Suwon 16419 , Republic of Korea
| | - Sung Wng Kim
- Department of Energy Science , Sungkyunkwan University , Suwon 16419 , Republic of Korea
| | - Jeongyong Kim
- Department of Energy Science , Sungkyunkwan University , Suwon 16419 , Republic of Korea
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26
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Zheliuk O, Lu JM, Chen QH, Yumin AAE, Golightly S, Ye JT. Josephson coupled Ising pairing induced in suspended MoS 2 bilayers by double-side ionic gating. NATURE NANOTECHNOLOGY 2019; 14:1123-1128. [PMID: 31686006 DOI: 10.1038/s41565-019-0564-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 09/26/2019] [Indexed: 06/10/2023]
Abstract
Superconductivity in monolayer transition metal dichalcogenides is characterized by Ising-type pairing induced via a strong Zeeman-type spin-orbit coupling. When two transition metal dichalcogenides layers are coupled, more exotic superconducting phases emerge, which depend on the ratio of Ising-type protection and interlayer coupling strength. Here, we induce superconductivity in suspended MoS2 bilayers and unveil a coupled superconducting state with strong Ising-type spin-orbit coupling. Gating the bilayer symmetrically from both sides by ionic liquid gating varies the interlayer interaction and accesses electronic states with broken local inversion symmetry while maintaining the global inversion symmetry. We observe a strong suppression of the Ising protection that evidences a coupled superconducting state. The symmetric gating scheme not only induces superconductivity in both atomic sheets but also controls the Josephson coupling between the layers, which gives rise to a dimensional crossover in the bilayer.
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Affiliation(s)
- O Zheliuk
- Device Physics of Complex Materials, Zernike Institute for Advanced Materials, University of Groningen, Groningen, the Netherlands
| | - J M Lu
- Device Physics of Complex Materials, Zernike Institute for Advanced Materials, University of Groningen, Groningen, the Netherlands
- High Field Magnet Laboratory, Radboud University, Nijmegen, the Netherlands
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing, China
| | - Q H Chen
- Device Physics of Complex Materials, Zernike Institute for Advanced Materials, University of Groningen, Groningen, the Netherlands
| | - A A El Yumin
- Device Physics of Complex Materials, Zernike Institute for Advanced Materials, University of Groningen, Groningen, the Netherlands
| | - S Golightly
- Device Physics of Complex Materials, Zernike Institute for Advanced Materials, University of Groningen, Groningen, the Netherlands
| | - J T Ye
- Device Physics of Complex Materials, Zernike Institute for Advanced Materials, University of Groningen, Groningen, the Netherlands.
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27
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Ghosh R, Yadav K, Kataria M, Lin HI, Paul Inbaraj CR, Liao YM, Nguyen Y, Lu CH, Hofmann M, Sankar R, Shih WH, Hsieh YP, Chen YF. Heavy Mediator at Quantum Dot/Graphene Heterojunction for Efficient Charge Carrier Transfer: Alternative Approach for High-Performance Optoelectronic Devices. ACS APPLIED MATERIALS & INTERFACES 2019; 11:26518-26527. [PMID: 31283174 DOI: 10.1021/acsami.9b08294] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Two-dimensional (2D) material nanocomposites have emerged as a material system for discovering new physical phenomena and developing novel devices. However, because of the low density of states of most two-dimensional materials such as graphene, the heterostructure of nanocomposites suffers from an enhanced depletion region, which can greatly reduce the efficiency of the charge carrier transfer and deteriorate the device performance. To circumvent this difficulty, here we propose an alternative approach by inserting a second 2D mediator with a heavy effective mass having a large density of states in-between the heterojunction of 2D nanocomposites. The mediator can effectively reduce the depletion region and form a type-II band alignment, which can speed up the dissociation of electron-hole pairs and enhance charge carrier transfer. To illustrate the principle, we demonstrate a novel stretchable photodetector based on the combination of graphene/ReS2/perovskite quantum dots. Two-dimensional ReS2 acts as a mediator in-between highly absorbing perovskite quantum dots and a high-mobility graphene channel and a thiol-based linker between the ReS2 and the perovskite. It is found that the optical sensitivity can be enhanced by 22 times. This enhancement was ascribed to the improvement of the charge transfer efficiency as evidenced by optical spectroscopy measurements. The produced photosensors are capable of reaching the highest reported value of photoresponsivity (>107 A W-1) and detectivity compared to previously studied stretchable devices. Mechanical robustness with tolerable strain up to 100% and excellent stability make our device ideal for future wearable electronics.
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Affiliation(s)
- Rapti Ghosh
- Department of Physics , National Central University , Chung-Li 320 , Taiwan
| | - Kanchan Yadav
- Nano Science and Technology Program, Taiwan International Graduate Program, Institute of Physics , Academia Sinica , Taipei 106 , Taiwan
| | - Monika Kataria
- Department of Physics , National Central University , Chung-Li 320 , Taiwan
| | | | - Christy Roshini Paul Inbaraj
- Nano Science and Technology Program, Taiwan International Graduate Program, Institute of Physics , Academia Sinica , Taipei 106 , Taiwan
- Department of Engineering and System Sciences , National Tsing Hua University , Hsinchu 30013 , Taiwan
| | - Yu-Ming Liao
- Nano Science and Technology Program, Taiwan International Graduate Program, Institute of Physics , Academia Sinica , Taipei 106 , Taiwan
| | | | - Cheng-Hsin Lu
- Department of Material Sciences and Engineering , Drexel University , Philadelphia , Pennsylvania 19104 , United States
| | | | - Raman Sankar
- Institute of Physics , Academia Sinica , Taipei 11529 , Taiwan
- Centre for Condensed Matter Sciences , National Taiwan University , Taipei 10617 , Taiwan
| | - Wei-Heng Shih
- Department of Material Sciences and Engineering , Drexel University , Philadelphia , Pennsylvania 19104 , United States
| | | | - Yang-Fang Chen
- Advanced Research Centre for Green Materials Science and Technology , National Taiwan University , Taipei , Taiwan
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28
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Ren X, Wang Y, Xie Z, Xue F, Leighton C, Frisbie CD. Gate-Tuned Insulator-Metal Transition in Electrolyte-Gated Transistors Based on Tellurene. NANO LETTERS 2019; 19:4738-4744. [PMID: 31181883 DOI: 10.1021/acs.nanolett.9b01827] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Tellurene is a recently discovered 2D material with high hole mobility and air stability, rendering it a good candidate for future applications in electronics, optoelectronics, and energy devices. However, the physical properties of tellurene remain poorly understood. In this paper, we report on the fabrication and characterization of high-performance electrolyte-gated transistors (EGTs) based on solution-grown tellurene flakes <30 nm in thickness. Both Hall measurements and resistance-temperature behavior down to 2 K are recorded at multiple gate voltages, and an electronic phase diagram is generated. The results show that it is possible to cross the insulator-metal transition in tellurene EGTs by tuning gate voltage, achieving mobility up to ∼500 cm2 V-1 s-1. In particular, a truly metallic 2D state is observed at gate-induced hole densities >1 × 1013 cm-2, as confirmed by the temperature dependence of resistance and magnetoresistance measurements. Wide-range tuning of the electronic ground state of tellurene is thus achievable in EGTs, opening up new opportunities to realize electrical control of its physical properties.
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Piatti E, Romanin D, Gonnelli RS. Mapping multi-valley Lifshitz transitions induced by field-effect doping in strained MoS 2 nanolayers. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:114002. [PMID: 30562728 DOI: 10.1088/1361-648x/aaf981] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Gate-induced superconductivity at the surface of nanolayers of semiconducting transition metal dichalcogenides (TMDs) has attracted a lot of attention in recent years, thanks to the sizeable transition temperature, robustness against in-plane magnetic fields beyond the Pauli limit, and hints to a non-conventional nature of the pairing. A key information necessary to unveil its microscopic origin is the geometry of the Fermi surface hosting the Cooper pairs as a function of field-effect doping, which is dictated by the filling of the inequivalent valleys at the K/K[Formula: see text] and Q/Q[Formula: see text] points of the Brillouin zone. Here, we achieve this by combining density functional theory calculations of the bandstructure with transport measurements on ion-gated 2H-MoS2 nanolayers. We show that, when the number of layers and the amount of strain are set to their experimental values, the Fermi level crosses the bottom of the high-energy valleys at Q/Q[Formula: see text] at doping levels where characteristic kinks in the transconductance are experimentally detected. We also develop a simple 2D model which is able to quantitatively describe the broadening of the kinks observed upon increasing temperature. We demonstrate that this combined approach can be employed to map the dependence of the Fermi surface of TMD nanolayers on field-effect doping, detect Lifshitz transitions, and provide a method to determine the amount of strain and spin-orbit splitting between sub-bands from electric transport measurements in real devices.
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Affiliation(s)
- Erik Piatti
- Department of Applied Science and Technology, Politecnico di Torino, 10129 Torino, Italy
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30
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Jadczak J, Kutrowska-Girzycka J, Smoleński T, Kossacki P, Huang YS, Bryja L. Exciton binding energy and hydrogenic Rydberg series in layered ReS 2. Sci Rep 2019; 9:1578. [PMID: 30733485 PMCID: PMC6367321 DOI: 10.1038/s41598-018-37655-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 12/12/2018] [Indexed: 11/18/2022] Open
Abstract
Unlike monolayers of transition metal dichalcogenides such as MoS2, which possess high in-plane symmetry, layered ReS2 exhibits reduced in-plane crystal symmetry with a distorted 1 T structure. This unique symmetry leads to anisotropic optical properties, very promising for light polarization devices. Here, we report on low temperature polarization-resolved emission and absorption measurements of excitons in ReS2 from bulk to monolayer. In photoluminescence and reflectivity contrast spectra we distinguish two strongly polarized excitons X1 and X2 with dipole vectors along different crystal directions, which persist from bulk down to monolayer. Basing on the PL and RC spectra of bulk crystals we determine the energy of the ground and first four excited states of both excitons, which follow the usual hydrogenic Rydberg series of energy levels of 3D excitonic states (En = Ry*/n2). From the numerical fit we estimate that the energy gap is direct and equal to 1671.7 meV and binding energy of X1 and X2 is equal to 117.5 and 86.6 meV, respectively. In magneto-PL spectra of bulk ReS2 up to B = 10 T, the energy shift of all the states is below 2 meV. On reducing the crystal thickness from bulk to monolayer the ground state experience a strong blue shift.
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Affiliation(s)
- J Jadczak
- Department of Experimental Physics, Wroclaw University of Science and Technology, Wroclaw, Poland.
| | - J Kutrowska-Girzycka
- Department of Experimental Physics, Wroclaw University of Science and Technology, Wroclaw, Poland
| | - T Smoleński
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Warsaw, Poland
| | - P Kossacki
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Warsaw, Poland
| | - Y S Huang
- Department of Electronic Engineering, National Taiwan University of Science and Technology, Taipei, 106, Taiwan
| | - L Bryja
- Department of Experimental Physics, Wroclaw University of Science and Technology, Wroclaw, Poland
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31
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Zhou L, Zhang Y, Zhuo Z, Neukirch AJ, Tretiak S. Interlayer-Decoupled Sc-Based Mxene with High Carrier Mobility and Strong Light-Harvesting Ability. J Phys Chem Lett 2018; 9:6915-6920. [PMID: 30472850 DOI: 10.1021/acs.jpclett.8b03077] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Two-dimensional (2D) van der Waals (vdW) layered materials offer a unique combination of electronic and structural properties attractive for technological applications. Most of them show strong vdW interactions, which lead to interlayer-coupled optoelectronic properties due to quantum confinement. Here we present a systematic computational study of one Mxene, 2D double-metal-layered scandium chloride carbides (Sc2CCl2). Unlike conventional quantum-confined nanosystems, 2D Sc2CCl2 exhibits weak vdW interactions with robust interlayer-decoupled optoelectronic properties and extremely high and anisotropic carrier mobilities of about 1-4.5 × 104 cm2 V-1 s-1 that consequently produce comparatively large drain currents. Specifically, the 2D Sc2CCl2 family has strong light-harvesting ability and could be utilized as efficient donor materials in excitonic solar cells. Overall, in combination with high structural stability against ambient conditions, interlayer-decoupled robust optoelectronic properties potentially relax the requirements for the fabrication of high-quality monolayers and for selection of suitable substrates and suggest promising next-generation optoelectronic applications.
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Affiliation(s)
- Liujiang Zhou
- Theoretical Physics and Chemistry of Materials , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
- Center for Nonlinear Studies , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - Yu Zhang
- Theoretical Physics and Chemistry of Materials , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - Zhiwen Zhuo
- Center for Integrated Nanotechnologies , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - Amanda J Neukirch
- Theoretical Physics and Chemistry of Materials , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - Sergei Tretiak
- Theoretical Physics and Chemistry of Materials , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
- Center for Nonlinear Studies , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
- Hefei National Laboratory of Physical Sciences at the Microscale , University of Science and Technology of China , Hefei , Anhui 23026 , China
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32
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Bertolazzi S, Gobbi M, Zhao Y, Backes C, Samorì P. Molecular chemistry approaches for tuning the properties of two-dimensional transition metal dichalcogenides. Chem Soc Rev 2018; 47:6845-6888. [PMID: 30043037 DOI: 10.1039/c8cs00169c] [Citation(s) in RCA: 131] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Two-dimensional (2D) semiconductors, such as ultrathin layers of transition metal dichalcogenides (TMDs), offer a unique combination of electronic, optical and mechanical properties, and hold potential to enable a host of new device applications spanning from flexible/wearable (opto)electronics to energy-harvesting and sensing technologies. A critical requirement for developing practical and reliable electronic devices based on semiconducting TMDs consists in achieving a full control over their charge-carrier polarity and doping. Inconveniently, such a challenging task cannot be accomplished by means of well-established doping techniques (e.g. ion implantation and diffusion), which unavoidably damage the 2D crystals resulting in degraded device performances. Nowadays, a number of alternatives are being investigated, including various (supra)molecular chemistry approaches relying on the combination of 2D semiconductors with electroactive donor/acceptor molecules. As yet, a large variety of molecular systems have been utilized for functionalizing 2D TMDs via both covalent and non-covalent interactions. Such research endeavours enabled not only the tuning of the charge-carrier doping but also the engineering of the optical, electronic, magnetic, thermal and sensing properties of semiconducting TMDs for specific device applications. Here, we will review the most enlightening recent advancements in experimental (supra)molecular chemistry methods for tailoring the properties of atomically-thin TMDs - in the form of substrate-supported or solution-dispersed nanosheets - and we will discuss the opportunities and the challenges towards the realization of novel hybrid materials and devices based on 2D semiconductors and molecular systems.
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Affiliation(s)
- Simone Bertolazzi
- Université de Strasbourg, CNRS, ISIS, 8 alleé Gaspard Monge, 67000 Strasbourg, France.
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Piatti E, De Fazio D, Daghero D, Tamalampudi SR, Yoon D, Ferrari AC, Gonnelli RS. Multi-Valley Superconductivity in Ion-Gated MoS 2 Layers. NANO LETTERS 2018; 18:4821-4830. [PMID: 29949374 DOI: 10.1021/acs.nanolett.8b01390] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Layers of transition metal dichalcogenides (TMDs) combine the enhanced effects of correlations associated with the two-dimensional limit with electrostatic control over their phase transitions by means of an electric field. Several semiconducting TMDs, such as MoS2, develop superconductivity (SC) at their surface when doped with an electrostatic field, but the mechanism is still debated. It is often assumed that Cooper pairs reside only in the two electron pockets at the K/K' points of the Brillouin Zone. However, experimental and theoretical results suggest that a multivalley Fermi surface (FS) is associated with the SC state, involving six electron pockets at Q/Q'. Here, we perform low-temperature transport measurements in ion-gated MoS2 flakes. We show that a fully multivalley FS is associated with the SC onset. The Q/Q' valleys fill for doping ≳ 2 × 1013 cm-2, and the SC transition does not appear until the Fermi level crosses both spin-orbit split sub-bands Q 1 and Q 2. The SC state is associated with the FS connectivity and promoted by a Lifshitz transition due to the simultaneous population of multiple electron pockets. This FS topology will serve as a guideline in the quest for new superconductors.
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Affiliation(s)
- Erik Piatti
- Department of Applied Science and Technology , Politecnico di Torino , 10129 Torino , Italy
| | - Domenico De Fazio
- Cambridge Graphene Centre , University of Cambridge , Cambridge CB3 OFA , United Kingdom
| | - Dario Daghero
- Department of Applied Science and Technology , Politecnico di Torino , 10129 Torino , Italy
| | | | - Duhee Yoon
- Cambridge Graphene Centre , University of Cambridge , Cambridge CB3 OFA , United Kingdom
| | - Andrea C Ferrari
- Cambridge Graphene Centre , University of Cambridge , Cambridge CB3 OFA , United Kingdom
| | - Renato S Gonnelli
- Department of Applied Science and Technology , Politecnico di Torino , 10129 Torino , Italy
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34
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Hämäläinen J, Mattinen M, Mizohata K, Meinander K, Vehkamäki M, Räisänen J, Ritala M, Leskelä M. Atomic Layer Deposition of Rhenium Disulfide. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1703622. [PMID: 29315833 DOI: 10.1002/adma.201703622] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 09/08/2017] [Indexed: 06/07/2023]
Abstract
2D materials research is advancing rapidly as various new "beyond graphene" materials are fabricated, their properties studied, and materials tested in various applications. Rhenium disulfide is one of the 2D transition metal dichalcogenides that has recently shown to possess extraordinary properties such as that it is not limited by the strict monolayer thickness requirements. The unique inherent decoupling of monolayers in ReS2 combined with a direct bandgap and highly anisotropic properties makes ReS2 one of the most interesting 2D materials for a plethora of applications. Here, a highly controllable and precise atomic layer deposition (ALD) technique is applied to deposit ReS2 thin films. Film growth is demonstrated on large area (5 cm × 5 cm) substrates at moderate deposition temperatures between 120 and 500 °C, and the films are extensively characterized using field emission scanning electron microscopy/energy-dispersive X-ray spectroscopy, X-ray diffractometry using grazing incidence, atomic force microscopy, focused ion beam/transmission electron microscopy, X-ray photoelectron spectroscopy, and time-of-flight elastic recoil detection analysis techniques. The developed ReS2 ALD process highlights the potential of the material for applications beyond planar structure architectures. The ALD process also offers a route to an upgrade to an industrial scale.
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Affiliation(s)
- Jani Hämäläinen
- Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014, Helsinki, Finland
| | - Miika Mattinen
- Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014, Helsinki, Finland
| | - Kenichiro Mizohata
- Department of Physics, University of Helsinki, P.O. Box 64, FI-00014, Helsinki, Finland
| | - Kristoffer Meinander
- Department of Physics, University of Helsinki, P.O. Box 64, FI-00014, Helsinki, Finland
| | - Marko Vehkamäki
- Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014, Helsinki, Finland
| | - Jyrki Räisänen
- Department of Physics, University of Helsinki, P.O. Box 64, FI-00014, Helsinki, Finland
| | - Mikko Ritala
- Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014, Helsinki, Finland
| | - Markku Leskelä
- Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014, Helsinki, Finland
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35
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Zhang X, Lai Z, Ma Q, Zhang H. Novel structured transition metal dichalcogenide nanosheets. Chem Soc Rev 2018; 47:3301-3338. [PMID: 29671441 DOI: 10.1039/c8cs00094h] [Citation(s) in RCA: 149] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Ultrathin two-dimensional (2D) layered transition metal dichalcogenides (TMDs) have attracted considerable attention owing to their unique properties and great potential in a wide range of applications. Great efforts have been devoted to the preparation of novel-structured TMD nanosheets by engineering their intrinsic structures at the atomic scale. Until now, a lot of new-structured TMD nanosheets, such as vacancy-containing TMDs, heteroatom-doped TMDs, TMD alloys, 1T'/1T phase and in-plane TMD crystal-phase heterostructures, TMD heterostructures and Janus TMD nanosheets, have been prepared. These materials exhibit unique properties and hold great promise in various applications, including electronics/optoelectronics, thermoelectrics, catalysis, energy storage and conversion and biomedicine. This review focuses on the most recent important discoveries in the preparation, characterization and application of these new-structured ultrathin 2D layered TMDs.
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Affiliation(s)
- Xiao Zhang
- Center for Programmable Materials, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.
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36
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Full superconducting dome of strong Ising protection in gated monolayer WS 2. Proc Natl Acad Sci U S A 2018; 115:3551-3556. [PMID: 29555774 DOI: 10.1073/pnas.1716781115] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Many recent studies show that superconductivity not only exists in atomically thin monolayers but can exhibit enhanced properties such as a higher transition temperature and a stronger critical field. Nevertheless, besides being unstable in air, the weak tunability in these intrinsically metallic monolayers has limited the exploration of monolayer superconductivity, hindering their potential in electronic applications (e.g., superconductor-semiconductor hybrid devices). Here we show that using field effect gating, we can induce superconductivity in monolayer WS2 grown by chemical vapor deposition, a typical ambient-stable semiconducting transition metal dichalcogenide (TMD), and we are able to access a complete set of competing electronic phases over an unprecedented doping range from band insulator, superconductor, to a reentrant insulator at high doping. Throughout the superconducting dome, the Cooper pair spin is pinned by a strong internal spin-orbit interaction, making this material arguably the most resilient superconductor in the external magnetic field. The reentrant insulating state at positive high gating voltages is attributed to localization induced by the characteristically weak screening of the monolayer, providing insight into many dome-like superconducting phases observed in field-induced quasi-2D superconductors.
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37
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Ciarrocchi A, Avsar A, Ovchinnikov D, Kis A. Thickness-modulated metal-to-semiconductor transformation in a transition metal dichalcogenide. Nat Commun 2018; 9:919. [PMID: 29500434 PMCID: PMC5834615 DOI: 10.1038/s41467-018-03436-0] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 02/13/2018] [Indexed: 11/09/2022] Open
Abstract
The possibility of tailoring physical properties by changing the number of layers in van der Waals crystals is one of the driving forces behind the emergence of two-dimensional materials. One example is bulk MoS2, which changes from an indirect gap semiconductor to a direct bandgap semiconductor in the monolayer form. Here, we show a much bigger tuning range with a complete switching from a metal to a semiconductor in atomically thin PtSe2 as its thickness is reduced. Crystals with a thickness of ~13 nm show metallic behavior with a contact resistance as low as 70 Ω·µm. As they are thinned down to 2.5 nm and below, we observe semiconducting behavior. In such thin crystals, we demonstrate ambipolar transport with a bandgap smaller than 2.2 eV and an on/off ratio of ~105. Our results demonstrate that PtSe2 possesses an unusual behavior among 2D materials, enabling novel applications in nano and optoelectronics.
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Affiliation(s)
- Alberto Ciarrocchi
- Electrical Engineering Institute, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
- Institute of Materials Science and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Ahmet Avsar
- Electrical Engineering Institute, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
- Institute of Materials Science and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Dmitry Ovchinnikov
- Electrical Engineering Institute, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
- Institute of Materials Science and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Andras Kis
- Electrical Engineering Institute, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland.
- Institute of Materials Science and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland.
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38
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Sim S, Lee D, Trifonov AV, Kim T, Cha S, Sung JH, Cho S, Shim W, Jo MH, Choi H. Ultrafast quantum beats of anisotropic excitons in atomically thin ReS 2. Nat Commun 2018; 9:351. [PMID: 29367747 PMCID: PMC5783952 DOI: 10.1038/s41467-017-02802-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 12/27/2017] [Indexed: 12/02/2022] Open
Abstract
Quantum beats, periodic oscillations arising from coherent superposition states, have enabled exploration of novel coherent phenomena. Originating from strong Coulomb interactions and reduced dielectric screening, two-dimensional transition metal dichalcogenides exhibit strongly bound excitons either in a single structure or hetero-counterpart; however, quantum coherence between excitons is barely known to date. Here we observe exciton quantum beats in atomically thin ReS2 and further modulate the intensity of the quantum beats signal. Surprisingly, linearly polarized excitons behave like a coherently coupled three-level system exhibiting quantum beats, even though they exhibit anisotropic exciton orientations and optical selection rules. Theoretical studies are also provided to clarify that the observed quantum beats originate from pure quantum coherence, not from classical interference. Furthermore, we modulate on/off quantum beats only by laser polarization. This work provides an ideal laboratory toward polarization-controlled exciton quantum beats in two-dimensional materials.
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Affiliation(s)
- Sangwan Sim
- School of Electrical and Electronic Engineering, Yonsei University, Seoul, 120-749, Korea
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Pohang, 790-784, Korea
| | - Doeon Lee
- School of Electrical and Electronic Engineering, Yonsei University, Seoul, 120-749, Korea
| | - Artur V Trifonov
- Spin Optics Laboratory, St. Petersburg State University, St. Petersburg, 198504, Russia
| | - Taeyoung Kim
- School of Electrical and Electronic Engineering, Yonsei University, Seoul, 120-749, Korea
| | - Soonyoung Cha
- School of Electrical and Electronic Engineering, Yonsei University, Seoul, 120-749, Korea
| | - Ji Ho Sung
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Pohang, 790-784, Korea
- Division of Advanced Materials Science, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Pohang, 790-784, Korea
| | - Sungjun Cho
- Department of Materials Science and Engineering, Yonsei University, Seoul, 120-749, Korea
| | - Wooyoung Shim
- Department of Materials Science and Engineering, Yonsei University, Seoul, 120-749, Korea
| | - Moon-Ho Jo
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Pohang, 790-784, Korea.
- Division of Advanced Materials Science, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Pohang, 790-784, Korea.
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Pohang, 790-784, Korea.
| | - Hyunyong Choi
- School of Electrical and Electronic Engineering, Yonsei University, Seoul, 120-749, Korea.
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Zhang S, Mao N, Zhang N, Wu J, Tong L, Zhang J. Anomalous Polarized Raman Scattering and Large Circular Intensity Differential in Layered Triclinic ReS 2. ACS NANO 2017; 11:10366-10372. [PMID: 28992402 DOI: 10.1021/acsnano.7b05321] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The Raman tensor of a crystal is the derivative of its polarizability tensor and is dependent on the symmetries of the crystal and the Raman-active vibrational mode. The intensity of a particular mode is determined by the Raman selection rule, which involves the Raman tensor and the polarization configurations. For anisotropic two-dimensional (2D) layered crystals, polarized Raman scattering has been used to reveal the crystalline orientations. However, due to its complicated Raman tensors and optical birefringence, the polarized Raman scattering of triclinic 2D crystals has not been well studied yet. Herein, we report the anomalous polarized Raman scattering of 2D layered triclinic rhenium disulfide (ReS2) and show a large circular intensity differential (CID) of Raman scattering in ReS2 of different thicknesses. The origin of CID and the anomalous behavior in polarized Raman scattering were attributed to the appearance of nonzero off-diagonal Raman tensor elements and the phase factor owing to optical birefringence. This can provide a method to identify the vertical orientation of triclinic layered materials. These findings may help to further understand the Raman scattering process in 2D materials of low symmetry and may indicate important applications in chiral recognition by using 2D materials.
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Affiliation(s)
- Shishu Zhang
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, China
| | - Nannan Mao
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, China
| | - Na Zhang
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, China
| | - Juanxia Wu
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, China
| | - Lianming Tong
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, China
| | - Jin Zhang
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, China
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40
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Gehlmann M, Aguilera I, Bihlmayer G, Nemšák S, Nagler P, Gospodarič P, Zamborlini G, Eschbach M, Feyer V, Kronast F, Młyńczak E, Korn T, Plucinski L, Schüller C, Blügel S, Schneider CM. Direct Observation of the Band Gap Transition in Atomically Thin ReS 2. NANO LETTERS 2017; 17:5187-5192. [PMID: 28759250 DOI: 10.1021/acs.nanolett.7b00627] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
ReS2 is considered as a promising candidate for novel electronic and sensor applications. The low crystal symmetry of this van der Waals compound leads to a highly anisotropic optical, vibrational, and transport behavior. However, the details of the electronic band structure of this fascinating material are still largely unexplored. We present a momentum-resolved study of the electronic structure of monolayer, bilayer, and bulk ReS2 using k-space photoemission microscopy in combination with first-principles calculations. We demonstrate that the valence electrons in bulk ReS2 are-contrary to assumptions in recent literature-significantly delocalized across the van der Waals gap. Furthermore, we directly observe the evolution of the valence band dispersion as a function of the number of layers, revealing the transition from an indirect band gap in bulk ReS2 to a direct gap in the bilayer and the monolayer. We also find a significantly increased effective hole mass in single-layer crystals. Our results establish bilayer ReS2 as an advantageous building block for two-dimensional devices and van der Waals heterostructures.
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Affiliation(s)
- Mathias Gehlmann
- Peter Grünberg Institut PGI-6, Forschungszentrum Jülich and JARA , 52425 Jülich, Germany
| | - Irene Aguilera
- Peter Grünberg Institut PGI-1 and Institute for Advanced Simulation IAS-1, Forschungszentrum Jülich and JARA , 52425 Jülich, Germany
| | - Gustav Bihlmayer
- Peter Grünberg Institut PGI-1 and Institute for Advanced Simulation IAS-1, Forschungszentrum Jülich and JARA , 52425 Jülich, Germany
| | - Slavomír Nemšák
- Peter Grünberg Institut PGI-6, Forschungszentrum Jülich and JARA , 52425 Jülich, Germany
| | - Philipp Nagler
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg , 93053 Regensburg, Germany
| | - Pika Gospodarič
- Peter Grünberg Institut PGI-6, Forschungszentrum Jülich and JARA , 52425 Jülich, Germany
| | - Giovanni Zamborlini
- Peter Grünberg Institut PGI-6, Forschungszentrum Jülich and JARA , 52425 Jülich, Germany
| | - Markus Eschbach
- Peter Grünberg Institut PGI-6, Forschungszentrum Jülich and JARA , 52425 Jülich, Germany
| | - Vitaliy Feyer
- Peter Grünberg Institut PGI-6, Forschungszentrum Jülich and JARA , 52425 Jülich, Germany
| | - Florian Kronast
- Abteilung Materialien für grüne Spintronik, Helmholtz-Zentrum Berlin , 14109 Berlin, Germany
| | - Ewa Młyńczak
- Peter Grünberg Institut PGI-6, Forschungszentrum Jülich and JARA , 52425 Jülich, Germany
- Faculty of Physics and Applied Computer Science, AGH University of Science and Technology , 30-059 Kraków, Poland
| | - Tobias Korn
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg , 93053 Regensburg, Germany
| | - Lukasz Plucinski
- Peter Grünberg Institut PGI-6, Forschungszentrum Jülich and JARA , 52425 Jülich, Germany
| | - Christian Schüller
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg , 93053 Regensburg, Germany
| | - Stefan Blügel
- Peter Grünberg Institut PGI-1 and Institute for Advanced Simulation IAS-1, Forschungszentrum Jülich and JARA , 52425 Jülich, Germany
| | - Claus M Schneider
- Peter Grünberg Institut PGI-6, Forschungszentrum Jülich and JARA , 52425 Jülich, Germany
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41
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Kühne M, Paolucci F, Popovic J, Ostrovsky PM, Maier J, Smet JH. Ultrafast lithium diffusion in bilayer graphene. NATURE NANOTECHNOLOGY 2017; 12:895-900. [PMID: 28581509 DOI: 10.1038/nnano.2017.108] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 04/28/2017] [Indexed: 05/12/2023]
Abstract
Solids that simultaneously conduct electrons and ions are key elements for the mass transfer and storage required in battery electrodes. Single-phase materials with a high electronic and high ionic conductivity at room temperature are hard to come by, and therefore multiphase systems with separate ion and electron channels have been put forward instead. Here we report on bilayer graphene as a single-phase mixed conductor that demonstrates Li diffusion faster than in graphite and even surpassing the diffusion of sodium chloride in liquid water. To measure Li diffusion, we have developed an on-chip electrochemical cell architecture in which the redox reaction that forces Li intercalation is localized only at a protrusion of the device so that the graphene bilayer remains unperturbed from the electrolyte during operation. We performed time-dependent Hall measurements across spatially displaced Hall probes to monitor the in-plane Li diffusion kinetics within the graphene bilayer and measured a diffusion coefficient as high as 7 × 10-5 cm2 s-1.
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Affiliation(s)
- Matthias Kühne
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
| | - Federico Paolucci
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, 56126 Pisa, Italy
| | - Jelena Popovic
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
| | - Pavel M Ostrovsky
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
- L. D. Landau Institute for Theoretical Physics RAS, 119334 Moscow, Russia
| | - Joachim Maier
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
| | - Jurgen H Smet
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
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42
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Kim H, Ovchinnikov D, Deiana D, Unuchek D, Kis A. Suppressing Nucleation in Metal-Organic Chemical Vapor Deposition of MoS 2 Monolayers by Alkali Metal Halides. NANO LETTERS 2017; 17:5056-5063. [PMID: 28700239 DOI: 10.1021/acs.nanolett.7b02311] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Toward the large-area deposition of MoS2 layers, we employ metal-organic precursors of Mo and S for a facile and reproducible van der Waals epitaxy on c-plane sapphire. Exposing c-sapphire substrates to alkali metal halide salts such as KI or NaCl together with the Mo precursor prior to the start of the growth process results in increasing the lateral dimensions of single crystalline domains by more than 2 orders of magnitude. The MoS2 grown this way exhibits high crystallinity and optoelectronic quality comparable to single-crystal MoS2 produced by conventional chemical vapor deposition methods. The presence of alkali metal halides suppresses the nucleation and enhances enlargement of domains while resulting in chemically pure MoS2 after transfer. Field-effect measurements in polymer electrolyte-gated devices result in promising electron mobility values close to 100 cm2 V-1 s-1 at cryogenic temperatures.
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Affiliation(s)
- HoKwon Kim
- Electrical Engineering Institute, École Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland
- Institute of Materials Science and Engineering, École Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland
| | - Dmitry Ovchinnikov
- Electrical Engineering Institute, École Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland
- Institute of Materials Science and Engineering, École Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland
| | - Davide Deiana
- Interdisciplinary Center for Electron Microscopy (CIME), École Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland
| | - Dmitrii Unuchek
- Electrical Engineering Institute, École Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland
- Institute of Materials Science and Engineering, École Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland
| | - Andras Kis
- Electrical Engineering Institute, École Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland
- Institute of Materials Science and Engineering, École Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland
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43
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Chen MW, Ovchinnikov D, Lazar S, Pizzochero M, Whitwick MB, Surrente A, Baranowski M, Sanchez OL, Gillet P, Plochocka P, Yazyev OV, Kis A. Highly Oriented Atomically Thin Ambipolar MoSe 2 Grown by Molecular Beam Epitaxy. ACS NANO 2017; 11:6355-6361. [PMID: 28530829 PMCID: PMC5492213 DOI: 10.1021/acsnano.7b02726] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 05/22/2017] [Indexed: 05/19/2023]
Abstract
Transition metal dichalcogenides (TMDCs), together with other two-dimensional (2D) materials, have attracted great interest due to the unique optical and electrical properties of atomically thin layers. In order to fulfill their potential, developing large-area growth and understanding the properties of TMDCs have become crucial. Here, we have used molecular beam epitaxy (MBE) to grow atomically thin MoSe2 on GaAs(111)B. No intermediate compounds were detected at the interface of as-grown films. Careful optimization of the growth temperature can result in the growth of highly aligned films with only two possible crystalline orientations due to broken inversion symmetry. As-grown films can be transferred onto insulating substrates, allowing their optical and electrical properties to be probed. By using polymer electrolyte gating, we have achieved ambipolar transport in MBE-grown MoSe2. The temperature-dependent transport characteristics can be explained by the 2D variable-range hopping (2D-VRH) model, indicating that the transport is strongly limited by the disorder in the film.
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Affiliation(s)
- Ming-Wei Chen
- Electrical
Engineering Institute, École Polytechnique
Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Institute
of Materials Science and Engineering, École
Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Dmitry Ovchinnikov
- Electrical
Engineering Institute, École Polytechnique
Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Institute
of Materials Science and Engineering, École
Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Sorin Lazar
- FEI
Electron Optics, 5600 KA Eindhoven, The Netherlands
| | - Michele Pizzochero
- Institute
of Physics, École Polytechnique Fédérale
de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Michael Brian Whitwick
- Electrical
Engineering Institute, École Polytechnique
Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Alessandro Surrente
- Laboratoire
National
des Champs Magnétiques Intenses CNRS-UGA-UPS-INSA, 143 avenue de Rangueil, 31400 Toulouse, France
| | - Michał Baranowski
- Laboratoire
National
des Champs Magnétiques Intenses CNRS-UGA-UPS-INSA, 143 avenue de Rangueil, 31400 Toulouse, France
- Department
of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wybrzeze Wyspianskiego 27, 50-370 Wrocław, Poland
| | - Oriol Lopez Sanchez
- Electrical
Engineering Institute, École Polytechnique
Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Institute
of Materials Science and Engineering, École
Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Philippe Gillet
- Institute
of Physics, École Polytechnique Fédérale
de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Paulina Plochocka
- Laboratoire
National
des Champs Magnétiques Intenses CNRS-UGA-UPS-INSA, 143 avenue de Rangueil, 31400 Toulouse, France
| | - Oleg V. Yazyev
- Institute
of Physics, École Polytechnique Fédérale
de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Andras Kis
- Electrical
Engineering Institute, École Polytechnique
Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Institute
of Materials Science and Engineering, École
Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- E-mail:
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44
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Ho CH, Liu ZZ, Lin MH. Direct and indirect light emissions from layered ReS 2-x Se x (0 ≤ x ≤ 2). NANOTECHNOLOGY 2017; 28:235203. [PMID: 28516896 DOI: 10.1088/1361-6528/aa6f51] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
ReS2 and ReSe2 have recently been enthusiastically studied owing to the specific in-plane electrical, optical and structural anisotropy caused by their distorted one-layer trigonal (1 T) phase, whereas other traditional transition-metal dichalcogenides (TMDCs, e.g. MoS2 and WSe2) have a hexagonal structure. Because of this special property, more and versatile nano-electronics and nano-optoelectronics devices can be developed. In this work, 2D materials in the series ReS2-x Se x (0 ≤ x ≤ 2) have been successfully grown by the method of chemical vapor transport. The direct and indirect resonant emissions of the complete series of layers can be simultaneously detected by polarized micro-photoluminescence (μPL) spectroscopy when the thickness of the ReS2-x Se x is greater than ∼70 nm. When it is less than 70 nm, only three direct excitonic emissions-E 1ex, E 2ex and E Sex-are detected. For the thick (bulk) ReS2-x Se x , more stacking of the ReX2 monolayers even flattens and shifts the valence-band maximum from Γ to the other K- or M-related points, thus leading to the coexistence of direct and indirect resonant light emissions from the c-plane ReX2. The transmittance absorption edge of each bulk ReX2 (a few microns thick) usually has a lower energy than those of the direct E 1ex and E 2ex excitonic emissions to form indirect absorption. The coexistence of direct and indirect emissions in ReX2 is a unique characteristic of a 2D layered semiconductor possessing triclinic low symmetry.
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Affiliation(s)
- Ching-Hwa Ho
- Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 106, Taiwan. Graduate Institute of Electro-Optical Engineering and Department of Electronic and Computer Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan
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45
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Obodo KO, Ouma CNM, Obodo JT, Braun M. Influence of transition metal doping on the electronic and optical properties of ReS2 and ReSe2 monolayers. Phys Chem Chem Phys 2017; 19:19050-19057. [DOI: 10.1039/c7cp03455e] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We investigate the structural, electronic and optical properties of transition metal doped triclinic monolayered rhenium disulfide and diselenide (ReS2 and ReSe2) by means of quantum mechanical calculations.
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Affiliation(s)
| | - Cecil Napthaly Moro Ouma
- Natural Resources and Environment
- Council for Scientific and Industrial Research
- Pretoria
- South Africa
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