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Norimatsu W. A Review on Carrier Mobilities of Epitaxial Graphene on Silicon Carbide. MATERIALS (BASEL, SWITZERLAND) 2023; 16:7668. [PMID: 38138815 PMCID: PMC10744437 DOI: 10.3390/ma16247668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 12/11/2023] [Accepted: 12/14/2023] [Indexed: 12/24/2023]
Abstract
Graphene growth by thermal decomposition of silicon carbide (SiC) is a technique that produces wafer-scale, single-orientation graphene on an insulating substrate. It is often referred to as epigraphene, and has been thought to be suitable for electronics applications. In particular, high-frequency devices for communication technology or large quantum Hall plateau for metrology applications using epigraphene are expected, which require high carrier mobility. However, the carrier mobility of as-grown epigraphene exhibit the relatively low values of about 1000 cm2/Vs. Fortunately, we can hope to improve this situation by controlling the electronic state of epigraphene by modifying the surface and interface structures. In this paper, the mobility of epigraphene and the factors that govern it will be described, followed by a discussion of attempts that have been made to improve mobility in this field. These understandings are of great importance for next-generation high-speed electronics using graphene.
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Affiliation(s)
- Wataru Norimatsu
- Faculty of Science and Engineering, Waseda University, Tokyo 169-8555, Japan
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2
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Tseng CC, Song T, Jiang Q, Lin Z, Wang C, Suh J, Watanabe K, Taniguchi T, McGuire MA, Xiao D, Chu JH, Cobden DH, Xu X, Yankowitz M. Gate-Tunable Proximity Effects in Graphene on Layered Magnetic Insulators. NANO LETTERS 2022; 22:8495-8501. [PMID: 36279401 DOI: 10.1021/acs.nanolett.2c02931] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The extreme versatility of van der Waals materials originates from their ability to exhibit new electronic properties when assembled in close proximity to dissimilar crystals. For example, although graphene is inherently nonmagnetic, recent work has reported a magnetic proximity effect in graphene interfaced with magnetic substrates, potentially enabling a pathway toward achieving a high-temperature quantum anomalous Hall effect. Here, we investigate heterostructures of graphene and chromium trihalide magnetic insulators (CrI3, CrBr3, and CrCl3). Surprisingly, we are unable to detect a magnetic exchange field in the graphene but instead discover proximity effects featuring unprecedented gate tunability. The graphene becomes highly hole-doped due to charge transfer from the neighboring magnetic insulator and further exhibits a variety of atypical gate-dependent transport features. The charge transfer can additionally be altered upon switching the magnetic states of the nearest CrI3 layers. Our results provide a roadmap for exploiting proximity effects arising in graphene coupled to magnetic insulators.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Michael A McGuire
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee37831, United States
| | - Di Xiao
- Pacific Northwest National Laboratory, Richland, Washington99354, United States
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Chau TK, Suh D, Kang H. Quantum Hall Effect across Graphene Grain Boundary. MATERIALS (BASEL, SWITZERLAND) 2021; 15:8. [PMID: 35009154 PMCID: PMC8745786 DOI: 10.3390/ma15010008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 12/17/2021] [Accepted: 12/18/2021] [Indexed: 06/14/2023]
Abstract
Charge carrier scattering at grain boundaries (GBs) in a chemical vapor deposition (CVD) graphene reduces the carrier mobility and degrades the performance of the graphene device, which is expected to affect the quantum Hall effect (QHE). This study investigated the influence of individual GBs on the QH state at different stitching angles of the GB in a monolayer CVD graphene. The measured voltage probes of the equipotential line in the QH state showed that the longitudinal resistance (Rxx) was affected by the scattering of the GB only in the low carrier concentration region, and the standard QHE of a monolayer graphene was observed regardless of the stitching angle of the GB. In addition, a controlled device with an added metal bar placed in the middle of the Hall bar configuration was introduced. Despite the fact that the equipotential lines in the controlled device were broken by the additional metal bar, only the Rxx was affected by nonzero resistance, whereas the Hall resistance (Rxy) revealed the well-quantized plateaus in the QH state. Thus, our study clarifies the effect of individual GBs on the QH states of graphenes.
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Affiliation(s)
- Tuan Khanh Chau
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Korea;
| | - Dongseok Suh
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Korea;
| | - Haeyong Kang
- Department of Physics, Pusan National University, Busan 46241, Korea
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4
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Gruschwitz M, Ghosal C, Shen TH, Wolff S, Seyller T, Tegenkamp C. Surface Transport Properties of Pb-Intercalated Graphene. MATERIALS 2021; 14:ma14247706. [PMID: 34947298 PMCID: PMC8705698 DOI: 10.3390/ma14247706] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 12/06/2021] [Accepted: 12/09/2021] [Indexed: 11/26/2022]
Abstract
Intercalation experiments on epitaxial graphene are attracting a lot of attention at present as a tool to further boost the electronic properties of 2D graphene. In this work, we studied the intercalation of Pb using buffer layers on 6H-SiC(0001) by means of electron diffraction, scanning tunneling microscopy, photoelectron spectroscopy and in situ surface transport. Large-area intercalation of a few Pb monolayers succeeded via surface defects. The intercalated Pb forms a characteristic striped phase and leads to formation of almost charge neutral graphene in proximity to a Pb layer. The Pb intercalated layer consists of 2 ML and shows a strong structural corrugation. The epitaxial heterostructure provides an extremely high conductivity of σ=100 mS/□. However, at low temperatures (70 K), we found a metal-insulator transition that we assign to the formation of minigaps in epitaxial graphene, possibly induced by a static distortion of graphene following the corrugation of the interface layer.
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Electronic and Transport Properties of Epitaxial Graphene on SiC and 3C-SiC/Si: A Review. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10124350] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The electronic and transport properties of epitaxial graphene are dominated by the interactions the material makes with its surroundings. Based on the transport properties of epitaxial graphene on SiC and 3C-SiC/Si substrates reported in the literature, we emphasize that the graphene interfaces formed between the active material and its environment are of paramount importance, and how interface modifications enable the fine-tuning of the transport properties of graphene. This review provides a renewed attention on the understanding and engineering of epitaxial graphene interfaces for integrated electronics and photonics applications.
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6
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Rigosi AF, Elmquist RE. The Quantum Hall Effect in the Era of the New SI. SEMICONDUCTOR SCIENCE AND TECHNOLOGY 2019; 34:10.1088/1361-6641/ab37d3. [PMID: 32165778 PMCID: PMC7067285 DOI: 10.1088/1361-6641/ab37d3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The quantum Hall effect (QHE), and devices reliant on it, will continue to serve as the foundation of the ohm while also expanding its territory into other SI derived units. The foundation, evolution, and significance of all of these devices exhibiting some form of the QHE will be described in the context of optimizing future electrical resistance standards. As the world adapts to using the quantum SI, it remains essential that the global metrology community pushes forth and continues to innovate and produce new technologies for disseminating the ohm and other electrical units.
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Affiliation(s)
- Albert F Rigosi
- Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, United States of America
| | - Randolph E Elmquist
- Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, United States of America
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Kudrynskyi ZR, Bhuiyan MA, Makarovsky O, Greener JDG, Vdovin EE, Kovalyuk ZD, Cao Y, Mishchenko A, Novoselov KS, Beton PH, Eaves L, Patanè A. Giant Quantum Hall Plateau in Graphene Coupled to an InSe van der Waals Crystal. PHYSICAL REVIEW LETTERS 2017; 119:157701. [PMID: 29077458 DOI: 10.1103/physrevlett.119.157701] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Indexed: 05/07/2023]
Abstract
We report on a "giant" quantum Hall effect plateau in a graphene-based field-effect transistor where graphene is capped by a layer of the van der Waals crystal InSe. The giant quantum Hall effect plateau arises from the close alignment of the conduction band edge of InSe with the Dirac point of graphene. This feature enables the magnetic-field- and electric-field-effect-induced transfer of charge carriers between InSe and the degenerate Landau level states of the adjacent graphene layer, which is coupled by a van der Waals heterointerface to the InSe.
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Affiliation(s)
- Z R Kudrynskyi
- School of Physics and Astronomy, The University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - M A Bhuiyan
- School of Physics and Astronomy, The University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - O Makarovsky
- School of Physics and Astronomy, The University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - J D G Greener
- School of Physics and Astronomy, The University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - E E Vdovin
- School of Physics and Astronomy, The University of Nottingham, Nottingham NG7 2RD, United Kingdom
- Institute of Microelectronics Technology and High Purity Materials, RAS, Chernogolovka 142432, Russia
| | - Z D Kovalyuk
- Institute for Problems of Materials Science, The National Academy of Sciences of Ukraine, Chernivtsi Branch, Chernivtsi 58001, Ukraine
| | - Y Cao
- School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
- National Graphene Institute, University of Manchester, Manchester M13 9PL, United Kingdom
| | - A Mishchenko
- School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - K S Novoselov
- School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - P H Beton
- School of Physics and Astronomy, The University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - L Eaves
- School of Physics and Astronomy, The University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - A Patanè
- School of Physics and Astronomy, The University of Nottingham, Nottingham NG7 2RD, United Kingdom
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8
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Yang M, Couturaud O, Desrat W, Consejo C, Kazazis D, Yakimova R, Syväjärvi M, Goiran M, Béard J, Frings P, Pierre M, Cresti A, Escoffier W, Jouault B. Puddle-Induced Resistance Oscillations in the Breakdown of the Graphene Quantum Hall Effect. PHYSICAL REVIEW LETTERS 2016; 117:237702. [PMID: 27982608 DOI: 10.1103/physrevlett.117.237702] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Indexed: 06/06/2023]
Abstract
We report on the stability of the quantum Hall plateau in wide Hall bars made from a chemically gated graphene film grown on SiC. The ν=2 quantized plateau appears from fields B≃5 T and persists up to B≃80 T. At high current density, in the breakdown regime, the longitudinal resistance oscillates with a 1/B periodicity and an anomalous phase, which we relate to the presence of additional electron reservoirs. The high field experimental data suggest that these reservoirs induce a continuous increase of the carrier density up to the highest available magnetic field, thus enlarging the quantum plateaus. These in-plane inhomogeneities, in the form of high carrier density graphene pockets, modulate the quantum Hall effect breakdown and decrease the breakdown current.
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Affiliation(s)
- M Yang
- Laboratoire National des Champs Magnétiques Intenses, EMFL-LNCMI, INSA, UPS, CNRS UPR 3228, Université de Toulouse, 143 avenue de Rangueil, 31400 Toulouse, France
| | - O Couturaud
- Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Université de Montpellier, 34095 Montpellier, France
| | - W Desrat
- Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Université de Montpellier, 34095 Montpellier, France
| | - C Consejo
- Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Université de Montpellier, 34095 Montpellier, France
| | - D Kazazis
- Centre de Nanosciences et de Nanotechnologies, CNRS, Université Paris-Sud, Université Paris-Saclay, C2N Marcoussis, 91460 Marcoussis, France
- Laboratory for Micro and Nanotechnology, Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland
| | - R Yakimova
- Department of Physics, Chemistry and Biology, Linköping University, SE-58183 Linköping, Sweden
| | - M Syväjärvi
- Department of Physics, Chemistry and Biology, Linköping University, SE-58183 Linköping, Sweden
| | - M Goiran
- Laboratoire National des Champs Magnétiques Intenses, EMFL-LNCMI, INSA, UPS, CNRS UPR 3228, Université de Toulouse, 143 avenue de Rangueil, 31400 Toulouse, France
| | - J Béard
- Laboratoire National des Champs Magnétiques Intenses, EMFL-LNCMI, INSA, UPS, CNRS UPR 3228, Université de Toulouse, 143 avenue de Rangueil, 31400 Toulouse, France
| | - P Frings
- Laboratoire National des Champs Magnétiques Intenses, EMFL-LNCMI, INSA, UPS, CNRS UPR 3228, Université de Toulouse, 143 avenue de Rangueil, 31400 Toulouse, France
| | - M Pierre
- Laboratoire National des Champs Magnétiques Intenses, EMFL-LNCMI, INSA, UPS, CNRS UPR 3228, Université de Toulouse, 143 avenue de Rangueil, 31400 Toulouse, France
| | - A Cresti
- Université Grenoble Alpes, IMEP-LAHC, F-38000 Grenoble, France
- CNRS, IMEP-LAHC, F-38000 Grenoble, France
| | - W Escoffier
- Laboratoire National des Champs Magnétiques Intenses, EMFL-LNCMI, INSA, UPS, CNRS UPR 3228, Université de Toulouse, 143 avenue de Rangueil, 31400 Toulouse, France
| | - B Jouault
- Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Université de Montpellier, 34095 Montpellier, France
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9
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Alexander-Webber JA, Huang J, Maude DK, Janssen TJBM, Tzalenchuk A, Antonov V, Yager T, Lara-Avila S, Kubatkin S, Yakimova R, Nicholas RJ. Giant quantum Hall plateaus generated by charge transfer in epitaxial graphene. Sci Rep 2016; 6:30296. [PMID: 27456765 PMCID: PMC4960615 DOI: 10.1038/srep30296] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 06/24/2016] [Indexed: 11/09/2022] Open
Abstract
Epitaxial graphene has proven itself to be the best candidate for quantum electrical resistance standards due to its wide quantum Hall plateaus with exceptionally high breakdown currents. However one key underlying mechanism, a magnetic field dependent charge transfer process, is yet to be fully understood. Here we report measurements of the quantum Hall effect in epitaxial graphene showing the widest quantum Hall plateau observed to date extending over 50 T, attributed to an almost linear increase in carrier density with magnetic field. This behaviour is strong evidence for field dependent charge transfer from charge reservoirs with exceptionally high densities of states in close proximity to the graphene. Using a realistic framework of broadened Landau levels we model the densities of donor states and predict the field dependence of charge transfer in excellent agreement with experimental results, thus providing a guide towards engineering epitaxial graphene for applications such as quantum metrology.
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Affiliation(s)
- J A Alexander-Webber
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - J Huang
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - D K Maude
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA, 143, avenue de Rangueil, 31400 Toulouse, France
| | - T J B M Janssen
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, United Kingdom
| | - A Tzalenchuk
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, United Kingdom.,Department of Physics, Royal Holloway, University of London, Egham TW20 0EX, United Kingdom
| | - V Antonov
- Department of Physics, Royal Holloway, University of London, Egham TW20 0EX, United Kingdom
| | - T Yager
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, S-412 96 Göteborg, Sweden
| | - S Lara-Avila
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, S-412 96 Göteborg, Sweden
| | - S Kubatkin
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, S-412 96 Göteborg, Sweden
| | - R Yakimova
- Department of Physics, Chemistry and Biology (IFM), Linköping University, S-581 83 Linköping, Sweden
| | - R J Nicholas
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
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10
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Ferrari AC, Bonaccorso F, Fal'ko V, Novoselov KS, Roche S, Bøggild P, Borini S, Koppens FHL, Palermo V, Pugno N, Garrido JA, Sordan R, Bianco A, Ballerini L, Prato M, Lidorikis E, Kivioja J, Marinelli C, Ryhänen T, Morpurgo A, Coleman JN, Nicolosi V, Colombo L, Fert A, Garcia-Hernandez M, Bachtold A, Schneider GF, Guinea F, Dekker C, Barbone M, Sun Z, Galiotis C, Grigorenko AN, Konstantatos G, Kis A, Katsnelson M, Vandersypen L, Loiseau A, Morandi V, Neumaier D, Treossi E, Pellegrini V, Polini M, Tredicucci A, Williams GM, Hong BH, Ahn JH, Kim JM, Zirath H, van Wees BJ, van der Zant H, Occhipinti L, Di Matteo A, Kinloch IA, Seyller T, Quesnel E, Feng X, Teo K, Rupesinghe N, Hakonen P, Neil SRT, Tannock Q, Löfwander T, Kinaret J. Science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems. NANOSCALE 2015; 7:4598-810. [PMID: 25707682 DOI: 10.1039/c4nr01600a] [Citation(s) in RCA: 991] [Impact Index Per Article: 110.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
We present the science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems, targeting an evolution in technology, that might lead to impacts and benefits reaching into most areas of society. This roadmap was developed within the framework of the European Graphene Flagship and outlines the main targets and research areas as best understood at the start of this ambitious project. We provide an overview of the key aspects of graphene and related materials (GRMs), ranging from fundamental research challenges to a variety of applications in a large number of sectors, highlighting the steps necessary to take GRMs from a state of raw potential to a point where they might revolutionize multiple industries. We also define an extensive list of acronyms in an effort to standardize the nomenclature in this emerging field.
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Affiliation(s)
- Andrea C Ferrari
- Cambridge Graphene Centre, University of Cambridge, Cambridge, CB3 0FA, UK.
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11
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Avsar A, Tan JY, Taychatanapat T, Balakrishnan J, Koon G, Yeo Y, Lahiri J, Carvalho A, Rodin AS, O’Farrell E, Eda G, Castro Neto AH, Özyilmaz B. Spin–orbit proximity effect in graphene. Nat Commun 2014; 5:4875. [DOI: 10.1038/ncomms5875] [Citation(s) in RCA: 350] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 07/31/2014] [Indexed: 01/13/2023] Open
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12
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Zhuang QD, Anyebe EA, Sanchez AM, Rajpalke MK, Veal TD, Zhukov A, Robinson BJ, Anderson F, Kolosov O, Fal’ko V. Graphitic platform for self-catalysed InAs nanowires growth by molecular beam epitaxy. NANOSCALE RESEARCH LETTERS 2014; 9:321. [PMID: 25024683 PMCID: PMC4094551 DOI: 10.1186/1556-276x-9-321] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 06/19/2014] [Indexed: 06/03/2023]
Abstract
We report the self-catalysed growth of InAs nanowires (NWs) on graphite thin films using molecular beam epitaxy via a droplet-assisted technique. Through optimising metal droplets, we obtained vertically aligned InAs NWs with highly uniform diameter along their entire length. In comparison with conventional InAs NWs grown on Si (111), the graphite surface led to significant effects on the NWs geometry grown on it, i.e. larger diameter, shorter length with lower number density, which were ascribed to the absence of dangling bonds on the graphite surface. The axial growth rate of the NWs has a strong dependence on growth time, which increases quickly in the beginning then slows down after the NWs reach a length of approximately 0.8 μm. This is attributed to the combined axial growth contributions from the surface impingement and sidewall impingement together with the desorption of adatoms during the diffusion. The growth of InAs NWs on graphite was proposed following a vapour-solid mechanism. High-resolution transmission electron microscopy reveals that the NW has a mixture of pure zinc-blende and wurtzite insertions.
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Affiliation(s)
- Qian D Zhuang
- Physics Department, Lancaster University, Lancaster LA1 4YB, UK
| | | | - Ana M Sanchez
- Department of Physics, University of Warwick, Coventry CV4 7AL, UK
| | - Mohana K Rajpalke
- Stephenson Institute for Renewable Energy and Department of Physics, University of Liverpool, Liverpool L69 7ZF, UK
| | - Tim D Veal
- Stephenson Institute for Renewable Energy and Department of Physics, University of Liverpool, Liverpool L69 7ZF, UK
| | - Alexander Zhukov
- Department of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK
| | | | | | - Oleg Kolosov
- Physics Department, Lancaster University, Lancaster LA1 4YB, UK
| | - Vladimir Fal’ko
- Physics Department, Lancaster University, Lancaster LA1 4YB, UK
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13
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Chua C, Connolly M, Lartsev A, Yager T, Lara-Avila S, Kubatkin S, Kopylov S, Fal'ko V, Yakimova R, Pearce R, Janssen TJBM, Tzalenchuk A, Smith CG. Quantum Hall effect and quantum point contact in bilayer-patched epitaxial graphene. NANO LETTERS 2014; 14:3369-3373. [PMID: 24848806 DOI: 10.1021/nl5008757] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We study an epitaxial graphene monolayer with bilayer inclusions via magnetotransport measurements and scanning gate microscopy at low temperatures. We find that bilayer inclusions can be metallic or insulating depending on the initial and gated carrier density. The metallic bilayers act as equipotential shorts for edge currents, while closely spaced insulating bilayers guide the flow of electrons in the monolayer constriction, which was locally gated using a scanning gate probe.
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Affiliation(s)
- Cassandra Chua
- Cavendish Laboratory, 19 JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
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