1
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Chen X, Jiang X, Zhang H. Boosting Electro- and Photo-Catalytic Activities in Atomically Thin Nanomaterials by Heterointerface Engineering. Materials (Basel) 2023; 16:5829. [PMID: 37687522 PMCID: PMC10488418 DOI: 10.3390/ma16175829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Revised: 08/06/2023] [Accepted: 08/16/2023] [Indexed: 09/10/2023]
Abstract
Since the discovery of graphene, two-dimensional ultrathin nanomaterials with an atomic thickness (typically <5 nm) have attracted tremendous interest due to their fascinating chemical and physical properties. These ultrathin nanomaterials, referred to as atomically thin materials (ATMs), possess inherent advantages such as a high specific area, highly exposed surface-active sites, efficient atom utilization, and unique electronic structures. While substantial efforts have been devoted to advancing ATMs through structural chemistry, the potential of heterointerface engineering to enhance their properties has not yet been fully recognized. Indeed, the introduction of bi- or multi-components to construct a heterointerface has emerged as a crucial strategy to overcome the limitations in property enhancement during ATM design. In this review, we aim to summarize the design principles of heterointerfacial ATMs, present general strategies for manipulating their interfacial structure and catalytic properties, and provide an overview of their application in energy conversion and storage, including the hydrogen evolution reaction (HER), the oxygen evolution reaction (OER), the oxygen reduction reaction (ORR), the CO2 electroreduction reaction (CO2RR), photocatalysis, and rechargeable batteries. The central theme of this review is to establish correlations among interfacial modulation, structural and electronic properties, and ATMs' major applications. Finally, based on the current research progress, we propose future directions that remain unexplored in interfacial ATMs for enhancing their properties and introducing novel functionalities in practical applications.
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Affiliation(s)
- Xingyu Chen
- School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Xinyue Jiang
- School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Hao Zhang
- School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China
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2
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de Carvalho LC, da Lapa RS, Alexandre SS, Nunes RW. Structural and thermodynamic properties of quasi-2D Mo (1-x)W x(S, Se, Te) 2monolayer alloys: a statistical first principle study. Nanotechnology 2023; 34:275704. [PMID: 36917839 DOI: 10.1088/1361-6528/acc406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Accepted: 03/14/2023] [Indexed: 06/18/2023]
Abstract
In this work, we report anab initiostudy of the structural and thermodynamic properties of two-dimensional transition-metal dichalcogenides (2D-TMDC) alloys, Mo(1-x)Wx(S, Se, Te)2, using the cluster expansion framework to compute the Helmholtz free energy of alloys as a function of alloy composition and temperature, in the framework of the generalized quasi-chemical approximation. We consider alloying only on the metal sublayer. Our results indicate a weak dependence of the structural properties (lattice constants, nearest-neighbor bond lengths, and layer width) on the alloy composition (i.e. concentrations of W and Mo atoms), in line with the very similar values of the atomic radii of Mo and W atoms. A stronger dependence on the chalcogen is obtained, a trend that reflects the larger variations in atomic radii among the three chalcogen species. As a function of composition, the structural parameters we examined show similar trends, with negligible bowing (i.e. deviations from a Vegard's law interpolation between end compounds), for the three alloys. Moreover, already at 300 K the behavior of these structural features as a function of composition is very similar to that of the standard-regular-solution (SRS) high-temperature limit. In contrast, the electronic band gaps of the the three alloys as a function of composition show small but significant bowing, as high as -1% to -2% near thex= 0.5 alloy composition. Similarly to the structural features, the band gaps attain the high-temperature SRS limit already at 300 K. Regarding thermodynamic properties, we obtain negative values of the internal energy of mixing for the three alloys over the full range of compositions. Therefore, the theoretical alloying phase diagram for the three alloys is featureless, with stability of a fully-mixed alloy at all temperatures and compositions, with no miscibility gap (hence no bimodal nor spinodal decomposition lines). The thermodynamic potentials (mixing internal energy, mixing entropy, and mixing free energy) reach the high-temperature limit at ∼1000 K, the temperature range of synthesis of 2D-TMDC alloys. These trends of structural and electronic properties of the 2D-TMDC alloys are due to the very similar atomic radii and the nearly identical coordination chemistry of Mo and W. Our results are in agreement with experimental work on the alloying of Mo and W atoms, for samples of Mo(1-x)WxS2monolayer alloys, that found that the random mixed alloy is the thermodynamically stable state for this alloy, with no segregation or phase separation.
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Affiliation(s)
- Luiz Cláudio de Carvalho
- Departamento de Física, ICEx, Universidade Federal de Minas Gerais, Caixa Postal 702, CEP 31270-901, Belo Horizonte, Minas Gerais, Brazil
| | - Rodrigo Santos da Lapa
- Departamento de Física, ICEx, Universidade Federal de Minas Gerais, Caixa Postal 702, CEP 31270-901, Belo Horizonte, Minas Gerais, Brazil
- Instituto de Ciências da Vida e da Natureza, Universidade Federal da Integração Latino-Americana, Caixa Postal 2044, Foz do Iguaçu, Brazil
| | - Simone Silva Alexandre
- Departamento de Física, ICEx, Universidade Federal de Minas Gerais, Caixa Postal 702, CEP 31270-901, Belo Horizonte, Minas Gerais, Brazil
| | - Ricardo Wagner Nunes
- Departamento de Física, ICEx, Universidade Federal de Minas Gerais, Caixa Postal 702, CEP 31270-901, Belo Horizonte, Minas Gerais, Brazil
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3
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Dou Y, Yuan D, Yu L, Zhang W, Zhang L, Fan K, Al-Mamun M, Liu P, He CT, Zhao H. Interpolation between W Dopant and Co Vacancy in CoOOH for Enhanced Oxygen Evolution Catalysis. Adv Mater 2022; 34:e2104667. [PMID: 34693576 DOI: 10.1002/adma.202104667] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 10/09/2021] [Indexed: 06/13/2023]
Abstract
Electronic structure engineering via integrating two defect structures with opposite modulation effects holds the key to fully unlocking the power of a catalyst. Herein, an interpolation principle is proposed to activate CoOOH via W doping and Co vacancies for the oxygen evolution reaction. Density functional theory suggests opposite roles for the W dopant and the Co vacancy but a synergy between them in tuning the electronic states of the Co site, leading to near-ideal intermediate energetics and dramatically lowered catalytic overpotential. Experimental studies confirm the modulation of the electronic structure and validate the greatly enhanced catalytic activity with a small overpotential of 298.5 mV to drive 50 mA cm-2 . The discovery of the interpolation between dopants and vacancies opens up a new methodology to design efficient catalysts for various electrochemical reactions.
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Affiliation(s)
- Yuhai Dou
- Centre for Catalysis and Clean Energy, Gold Coast Campus, Griffith University, Gold Coast, 4222, Australia
- Shandong Institute of Advanced Technology, Jinan, 250100, China
| | - Ding Yuan
- Centre for Catalysis and Clean Energy, Gold Coast Campus, Griffith University, Gold Coast, 4222, Australia
| | - Linping Yu
- Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation, Changsha University of Science and Technology, Changsha, 410114, China
| | - Weiping Zhang
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, China
| | - Lei Zhang
- Centre for Catalysis and Clean Energy, Gold Coast Campus, Griffith University, Gold Coast, 4222, Australia
| | - Kaicai Fan
- Centre for Catalysis and Clean Energy, Gold Coast Campus, Griffith University, Gold Coast, 4222, Australia
| | - Mohammad Al-Mamun
- Centre for Catalysis and Clean Energy, Gold Coast Campus, Griffith University, Gold Coast, 4222, Australia
| | - Porun Liu
- Centre for Catalysis and Clean Energy, Gold Coast Campus, Griffith University, Gold Coast, 4222, Australia
| | - Chun-Ting He
- Key Laboratory of Functional Small Organic Molecule, Ministry of Education, College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang, 330022, China
| | - Huijun Zhao
- Centre for Catalysis and Clean Energy, Gold Coast Campus, Griffith University, Gold Coast, 4222, Australia
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4
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Ghasemian MB, Zavabeti A, Mousavi M, Murdoch BJ, Christofferson AJ, Meftahi N, Tang J, Han J, Jalili R, Allioux FM, Mayyas M, Chen Z, Elbourne A, McConville CF, Russo SP, Ringer S, Kalantar-Zadeh K. Doping Process of 2D Materials Based on the Selective Migration of Dopants to the Interface of Liquid Metals. Adv Mater 2021; 33:e2104793. [PMID: 34510605 DOI: 10.1002/adma.202104793] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 07/23/2021] [Indexed: 06/13/2023]
Abstract
The introduction of trace impurities within the doping processes of semiconductors is still a technological challenge for the electronics industries. By taking advantage of the selective enrichment of liquid metal interfaces, and harvesting the doped metal oxide semiconductor layers, the complexity of the process can be mitigated and a high degree of control over the outcomes can be achieved. Here, a mechanism of natural filtering for the preparation of doped 2D semiconducting sheets based on the different migration tendencies of metallic elements in the bulk competing for enriching the interfaces is proposed. As a model, liquid metal alloys with different weight ratios of Sn and Bi in the bulk are employed for harvesting Bi2 O3 -doped SnO nanosheets. In this model, Sn shows a much stronger tendency than Bi to occupy surface sites of the Bi-Sn alloys, even at the very high concentrations of Bi in the bulk. This provides the opportunity for creating SnO 2D sheets with tightly controlled Bi2 O3 dopants. By way of example, it is demonstrated how such nanosheets could be made selective to both reducing and oxidizing environmental gases. The process demonstrated here offers significant opportunities for future synthesis and fabrication processes in the electronics industries.
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Affiliation(s)
- Mohammad B Ghasemian
- School of Chemical Engineering, University of New South Wales (UNSW), Sydney, New South Wales, 2052, Australia
| | - Ali Zavabeti
- School of Science, RMIT University, Melbourne, Victoria, 3001, Australia
- Department of Chemical Engineering, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Maedehsadat Mousavi
- School of Chemical Engineering, University of New South Wales (UNSW), Sydney, New South Wales, 2052, Australia
| | - Billy J Murdoch
- RMIT Microscopy and Microanalysis Facility, STEM College, RMIT University, Melbourne, Victoria, 3001, Australia
| | | | - Nastaran Meftahi
- ARC Centre of Excellence in Exciton Science, School of Science, RMIT University, Melbourne, Victoria, 3000, Australia
| | - Jianbo Tang
- School of Chemical Engineering, University of New South Wales (UNSW), Sydney, New South Wales, 2052, Australia
| | - Jialuo Han
- School of Chemical Engineering, University of New South Wales (UNSW), Sydney, New South Wales, 2052, Australia
| | - Rouhollah Jalili
- School of Chemical Engineering, University of New South Wales (UNSW), Sydney, New South Wales, 2052, Australia
| | - Francois-Marie Allioux
- School of Chemical Engineering, University of New South Wales (UNSW), Sydney, New South Wales, 2052, Australia
| | - Mohannad Mayyas
- School of Chemical Engineering, University of New South Wales (UNSW), Sydney, New South Wales, 2052, Australia
| | - Zibin Chen
- School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Aaron Elbourne
- School of Science, RMIT University, Melbourne, Victoria, 3001, Australia
| | - Chris F McConville
- School of Science, RMIT University, Melbourne, Victoria, 3001, Australia
- Institute for Frontier Materials, Deakin University, Geelong, Victoria, 3216, Australia
| | - Salvy P Russo
- ARC Centre of Excellence in Exciton Science, School of Science, RMIT University, Melbourne, Victoria, 3000, Australia
| | - Simon Ringer
- School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW, 2006, Australia
- Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Kourosh Kalantar-Zadeh
- School of Chemical Engineering, University of New South Wales (UNSW), Sydney, New South Wales, 2052, Australia
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5
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Lee M, Kang JH, Mujid F, Suh J, Ray A, Park C, Muller DA, Park J. Atomically Thin, Optically Isotropic Films with 3D Nanotopography. Nano Lett 2021; 21:7291-7297. [PMID: 34415174 PMCID: PMC8431725 DOI: 10.1021/acs.nanolett.1c02478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 08/16/2021] [Indexed: 06/13/2023]
Abstract
Flat optics aims for the on-chip miniaturization of optical systems for high-speed and low-power operation, with integration of thin and lightweight components. Here, we present atomically thin yet optically isotropic films realized by using three-dimensional (3D) topographic reconstruction of anisotropic two-dimensional (2D) films to balance the out-of-plane and in-plane optical responses on the subwavelength scale. We achieve this by conformal growth of monolayer transition metal dichalcogenide (TMD) films on nanodome-structured substrates. The resulting films show an order-of-magnitude increase in the out-of-plane susceptibility for enhanced angular performance, displaying polarization isotropy in the off-axis absorption, as well as improved photoluminescence emission profiles, compared to their flat-film counterparts. We further show that such 3D geometric programming of optical properties is applicable to different TMD materials, offering spectral generalization over for the entire visible range. Our approach presents a powerful platform for advancing the development of atomically thin flat optics with custom-designed light-matter interactions.
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Affiliation(s)
- Myungjae Lee
- James
Franck Institute, University of Chicago, Chicago, Illinois 60637, United States
| | - Jong-Hoon Kang
- Department
of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Fauzia Mujid
- Department
of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Joonki Suh
- Department
of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Ariana Ray
- Department
of Physics, Cornell University, Ithaca, New York 14853, United States
| | - Chibeom Park
- James
Franck Institute, University of Chicago, Chicago, Illinois 60637, United States
- Department
of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - David. A. Muller
- School
of Applied and Engineering Physics, Cornell
University, Ithaca, New York 14853, United
States
| | - Jiwoong Park
- James
Franck Institute, University of Chicago, Chicago, Illinois 60637, United States
- Department
of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
- Pritzker
School of Molecular Engineering, University
of Chicago, Chicago, Illinois 60637, United
States
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6
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Li Z, Sang L, Liu P, Yue Z, Fuhrer MS, Xue Q, Wang X. Atomically Thin Superconductors. Small 2021; 17:e1904788. [PMID: 32363776 DOI: 10.1002/smll.201904788] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Revised: 12/18/2019] [Accepted: 03/04/2020] [Indexed: 06/11/2023]
Abstract
In recent years, atomically thin superconductors, including atomically thin elemental superconductors, single layer FeSe films, and few-layer cuprate superconductors, have been studied extensively. This hot research field is mainly driven by the discovery of significant superconductivity enhancement and high-temperature interface superconductivity in single-layer FeSe films epitaxially grown on SrTiO3 substrates in 2012. This study has attracted tremendous research interest and generated more studies focusing on further enhancing superconductivity and finding the origin of the superconductivity. A few years later, research on atomically thin superconductors has extended to cuprate superconductors, unveiling many intriguing properties that have neither been proposed or observed previously. These new discoveries challenge the current theory regarding the superconducting mechanism of unconventional superconductors and indicate new directions on how to achieve high-transition-temperature superconductors. Herein, this exciting recent progress is briefly discussed, with a focus on the recent progress in identifying new atomically thin superconductors.
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Affiliation(s)
- Zhi Li
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), University of Wollongong, Wollongong, NSW, 2525, Australia
- Institute for Superconducting and Electronic Materials (ISEM), Australian Institute for Innovative Materials (AIIM), University of Wollongong, Wollongong, NSW, 2525, Australia
| | - Lina Sang
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), University of Wollongong, Wollongong, NSW, 2525, Australia
- Institute for Superconducting and Electronic Materials (ISEM), Australian Institute for Innovative Materials (AIIM), University of Wollongong, Wollongong, NSW, 2525, Australia
| | - Peng Liu
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), University of Wollongong, Wollongong, NSW, 2525, Australia
- Institute for Superconducting and Electronic Materials (ISEM), Australian Institute for Innovative Materials (AIIM), University of Wollongong, Wollongong, NSW, 2525, Australia
| | - Zengji Yue
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), University of Wollongong, Wollongong, NSW, 2525, Australia
- Institute for Superconducting and Electronic Materials (ISEM), Australian Institute for Innovative Materials (AIIM), University of Wollongong, Wollongong, NSW, 2525, Australia
| | - Michael S Fuhrer
- School of Physics and Astronomy, Monash University, Victoria, 3800, Australia
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), Monash University, Victoria, 3800, Australia
| | - Qikun Xue
- Collaborative Innovation Center of Quantum Matter, Beijing, 100871, China
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, 100084, China
| | - Xiaolin Wang
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), University of Wollongong, Wollongong, NSW, 2525, Australia
- Institute for Superconducting and Electronic Materials (ISEM), Australian Institute for Innovative Materials (AIIM), University of Wollongong, Wollongong, NSW, 2525, Australia
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7
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Krishnamurthi V, Khan H, Ahmed T, Zavabeti A, Tawfik SA, Jain SK, Spencer MJS, Balendhran S, Crozier KB, Li Z, Fu L, Mohiuddin M, Low MX, Shabbir B, Boes A, Mitchell A, McConville CF, Li Y, Kalantar-Zadeh K, Mahmood N, Walia S. Liquid-Metal Synthesized Ultrathin SnS Layers for High-Performance Broadband Photodetectors. Adv Mater 2020; 32:e2004247. [PMID: 32960475 DOI: 10.1002/adma.202004247] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 08/09/2020] [Indexed: 06/11/2023]
Abstract
Atomically thin materials face an ongoing challenge of scalability, hampering practical deployment despite their fascinating properties. Tin monosulfide (SnS), a low-cost, naturally abundant layered material with a tunable bandgap, displays properties of superior carrier mobility and large absorption coefficient at atomic thicknesses, making it attractive for electronics and optoelectronics. However, the lack of successful synthesis techniques to prepare large-area and stoichiometric atomically thin SnS layers (mainly due to the strong interlayer interactions) has prevented exploration of these properties for versatile applications. Here, SnS layers are printed with thicknesses varying from a single unit cell (0.8 nm) to multiple stacked unit cells (≈1.8 nm) synthesized from metallic liquid tin, with lateral dimensions on the millimeter scale. It is reveal that these large-area SnS layers exhibit a broadband spectral response ranging from deep-ultraviolet (UV) to near-infrared (NIR) wavelengths (i.e., 280-850 nm) with fast photodetection capabilities. For single-unit-cell-thick layered SnS, the photodetectors show upto three orders of magnitude higher responsivity (927 A W-1 ) than commercial photodetectors at a room-temperature operating wavelength of 660 nm. This study opens a new pathway to synthesize reproduceable nanosheets of large lateral sizes for broadband, high-performance photodetectors. It also provides important technological implications for scalable applications in integrated optoelectronic circuits, sensing, and biomedical imaging.
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Affiliation(s)
- Vaishnavi Krishnamurthi
- School of Engineering, RMIT University, 124 La Trobe Street, Melbourne, Victoria, 3001, Australia
| | - Hareem Khan
- School of Engineering, RMIT University, 124 La Trobe Street, Melbourne, Victoria, 3001, Australia
| | - Taimur Ahmed
- School of Engineering, RMIT University, 124 La Trobe Street, Melbourne, Victoria, 3001, Australia
- Functional Materials and Microsystems Research Group and the Micro Nano Research Facility, RMIT University, 124 La Trobe Street, Melbourne, Victoria, 3001, Australia
| | - Ali Zavabeti
- School of Engineering, RMIT University, 124 La Trobe Street, Melbourne, Victoria, 3001, Australia
- Department of Chemical Engineering, The University of Melbourne, Melbourne, Victoria, 3010, Australia
| | | | - Shubhendra Kumar Jain
- School of Engineering, RMIT University, 124 La Trobe Street, Melbourne, Victoria, 3001, Australia
- Functional Materials and Microsystems Research Group and the Micro Nano Research Facility, RMIT University, 124 La Trobe Street, Melbourne, Victoria, 3001, Australia
- Sensor Devices and Metrology Group, CSIR-National Physical Laboratory (CSIR-NPL), Dr K. S. Krishnan Road, New Delhi, 110012, India
- Academy of Scientific & Innovative Research, (AcSIR), CSIR-HRDC Campus, Ghaziabad, Uttar Pradesh, 201002, India
| | - Michelle J S Spencer
- School of Science, RMIT University, Melbourne, Victoria, 3001, Australia
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies, School of Science, RMIT University, GPO Box 2476, Melbourne, Victoria, 3001, Australia
| | | | - Kenneth B Crozier
- School of Physics, The University of Melbourne, Melbourne, Victoria, 3010, Australia
- Department of Electrical and Electronic Engineering, The University of Melbourne, Melbourne, Victoria, 3010, Australia
- Australian Research Council (ARC) Centre of Excellence for Transformative Meta-Optical Systems, The University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Ziyuan Li
- Department of Electronic Materials Engineering, Research School of Physics, The Australian National University, Canberra, ACT, 2601, Australia
| | - Lan Fu
- Department of Electronic Materials Engineering, Research School of Physics, The Australian National University, Canberra, ACT, 2601, Australia
- Australian Research Council (ARC) Centre of Excellence for Transformative Meta-Optical Systems, The Australian National University, Canberra, ACT, 2601, Australia
| | - Md Mohiuddin
- School of Engineering, RMIT University, 124 La Trobe Street, Melbourne, Victoria, 3001, Australia
| | - Mei Xian Low
- School of Engineering, RMIT University, 124 La Trobe Street, Melbourne, Victoria, 3001, Australia
- Functional Materials and Microsystems Research Group and the Micro Nano Research Facility, RMIT University, 124 La Trobe Street, Melbourne, Victoria, 3001, Australia
| | - Babar Shabbir
- Department of Materials Science and Engineering, Monash University, Clayton, Victoria, 3800, Australia
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), Monash University, Clayton, Victoria, 3800, Australia
| | - Andreas Boes
- School of Engineering, RMIT University, 124 La Trobe Street, Melbourne, Victoria, 3001, Australia
| | - Arnan Mitchell
- School of Engineering, RMIT University, 124 La Trobe Street, Melbourne, Victoria, 3001, Australia
| | | | - Yongxiang Li
- School of Engineering, RMIT University, 124 La Trobe Street, Melbourne, Victoria, 3001, Australia
| | - Kourosh Kalantar-Zadeh
- School of Chemical Engineering, University of New South Wales (UNSW), Sydney, New South Wales, 2052, Australia
| | - Nasir Mahmood
- School of Engineering, RMIT University, 124 La Trobe Street, Melbourne, Victoria, 3001, Australia
| | - Sumeet Walia
- School of Engineering, RMIT University, 124 La Trobe Street, Melbourne, Victoria, 3001, Australia
- Functional Materials and Microsystems Research Group and the Micro Nano Research Facility, RMIT University, 124 La Trobe Street, Melbourne, Victoria, 3001, Australia
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8
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Zheng S, Jo S, Kang K, Sun L, Zhao M, Watanabe K, Taniguchi T, Moon P, Myoung N, Yang H. Resonant Tunneling Spectroscopy to Probe the Giant Stark Effect in Atomically Thin Materials. Adv Mater 2020; 32:e1906942. [PMID: 32027062 DOI: 10.1002/adma.201906942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 12/13/2019] [Indexed: 06/10/2023]
Abstract
Each atomic layer in van der Waals heterostructures possesses a distinct electronic band structure that can be manipulated for unique device operations. In the precise device architecture, the subtle but critical band splits by the giant Stark effect between atomic layers, varied by the momentum of electrons and external electric fields in device operation, has not yet been demonstrated or applied to design original devices with the full potential of atomically thin materials. Here, resonant tunneling spectroscopy based on the negligible quantum capacitance of 2D semiconductors in resonant tunneling transistors is reported. The bandgaps and sub-band structures of various channel materials could be demonstrated by the new conceptual spectroscopy at the device scale without debatable quasiparticle effects. Moreover, the band splits by the giant Stark effect in the channel materials could be probed, overcoming the limitations of conventional optical, photoemission, and tunneling spectroscopy. The resonant tunneling spectroscopy reveals essential and practical information for novel device applications.
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Affiliation(s)
- Shoujun Zheng
- Department of Energy Science, Sungkyunkwan University, Suwon, 16419, Korea
| | - Sanghyun Jo
- Samsung Advanced Institute of Technology, Suwon, 16678, Korea
| | - Kyungrok Kang
- Department of Energy Science, Sungkyunkwan University, Suwon, 16419, Korea
| | - Linfeng Sun
- Department of Energy Science, Sungkyunkwan University, Suwon, 16419, Korea
| | - Mali Zhao
- Department of Energy Science, Sungkyunkwan University, Suwon, 16419, Korea
| | - Kenji Watanabe
- National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Takashi Taniguchi
- National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Pilkyung Moon
- New York University Shanghai and NYU-ECNU Institute of Physics at NYU Shanghai, Shanghai, 200122, China
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, 200122, China
| | - Nojoon Myoung
- Department of Physics Education, Chosun University, Gwangju, 61452, Korea
| | - Heejun Yang
- Department of Energy Science, Sungkyunkwan University, Suwon, 16419, Korea
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9
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Dragoman D. Tunable fractional Fourier transform implementation of electronic wave functions in atomically thin materials. Beilstein J Nanotechnol 2018; 9:1828-1833. [PMID: 30013876 PMCID: PMC6037016 DOI: 10.3762/bjnano.9.174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 06/07/2018] [Indexed: 06/08/2023]
Abstract
A tunable fractional Fourier transform of the quantum wave function of electrons satisfying either the Schrödinger or the Dirac equation can be implemented in an atomically thin material by a parabolic potential distribution applied on a direction transverse to that of electron propagation. The difference between the propagation lengths necessary to obtain a fractional Fourier transform of a given order in these two cases could be seen as a manifestation of the Berry phase. The Fourier transform of the electron wave function is a particular case of the fractional Fourier transform. If the input and output wave functions are discretized, this configuration implements in one step the discrete fractional Fourier transform, in particular the discrete Fourier transform, and thus can act as a coprocessor in integrated logic circuits.
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Affiliation(s)
- Daniela Dragoman
- University of Bucharest, Physics Faculty, P.O. Box MG-11, 077125 Bucharest, Romania
- Academy of Romanian Scientists, Splaiul Independentei 54, 050094, Bucharest, Romania
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10
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Abstract
Two-dimensional (2D) topological crystalline insulators (TCIs) were recently predicted in thin films of the SnTe class of IV-VI semiconductors, which can host metallic edge states protected by mirror symmetry. As thickness decreases, quantum confinement effect will increase and surpass the inverted gap below a critical thickness, turning TCIs into normal insulators. Surprisingly, based on first-principles calculations, here we demonstrate that (001) monolayers of rocksalt IV-VI semiconductors XY (X = Ge, Sn, Pb and Y = S, Se, Te) are 2D TCIs with the fundamental band gap as large as 260 meV in monolayer PbTe. This unexpected nontrivial topological phase stems from the strong crystal field effect in the monolayer, which lifts the degeneracy between p(x,y) and p(z) orbitals and leads to band inversion between cation pz and anion px,y orbitals. This crystal field effect induced topological phase offers a new strategy to find and design other atomically thin 2D topological materials.
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Affiliation(s)
- Junwei Liu
- †Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | | | - Liang Fu
- †Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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