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Bradford J, Dewes BT, Shiffa M, Cottam ND, Rahman K, Cheng TS, Novikov SV, Makarovsky O, O'Shea JN, Beton PH, Lara-Avila S, Harknett J, Greenaway MT, Patanè A. Epitaxy of GaSe Coupled to Graphene: From In Situ Band Engineering to Photon Sensing. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2404809. [PMID: 39169700 DOI: 10.1002/smll.202404809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2024] [Revised: 07/26/2024] [Indexed: 08/23/2024]
Abstract
2D semiconductors can drive advances in quantum science and technologies. However, they should be free of any contamination; also, the crystallographic ordering and coupling of adjacent layers and their electronic properties should be well-controlled, tunable, and scalable. Here, these challenges are addressed by a new approach, which combines molecular beam epitaxy and in situ band engineering in ultra-high vacuum of semiconducting gallium selenide (GaSe) on graphene. In situ studies by electron diffraction, scanning probe microscopy, and angle-resolved photoelectron spectroscopy reveal that atomically-thin layers of GaSe align in the layer plane with the underlying lattice of graphene. The GaSe/graphene heterostructure, referred to as 2semgraphene, features a centrosymmetric (group symmetry D3d) polymorph of GaSe, a charge dipole at the GaSe/graphene interface, and a band structure tunable by the layer thickness. The newly-developed, scalable 2semgraphene is used in optical sensors that exploit the photoactive GaSe layer and the built-in potential at its interface with the graphene channel. This proof of concept has the potential for further advances and device architectures that exploit 2semgraphene as a functional building block.
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Affiliation(s)
- Jonathan Bradford
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Benjamin T Dewes
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Mustaqeem Shiffa
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Nathan D Cottam
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Kazi Rahman
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Tin S Cheng
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Sergei V Novikov
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Oleg Makarovsky
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - James N O'Shea
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Peter H Beton
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Samuel Lara-Avila
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, Gothenburg, 412 96, Sweden
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UK
| | - Jordan Harknett
- Department of Physics, Loughborough University, Loughborough, LE11 3TU, UK
| | - Mark T Greenaway
- Department of Physics, Loughborough University, Loughborough, LE11 3TU, UK
| | - Amalia Patanè
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
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2
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Lin CY, Weng DW, Chiu CW, Gumbs G. Unique electronic and optical properties of stacking-modulated bilayer graphene under external magnetic fields. Phys Chem Chem Phys 2024; 26:19316-19331. [PMID: 38963725 DOI: 10.1039/d4cp01576b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/06/2024]
Abstract
This study delves into the magneto-electronic and magneto-optical properties of stacking-modulated bilayer graphene. By manipulating domain walls (DWs) across AB-BA domains periodically, we unveil oscillatory Landau subbands and the associated optical excitations. The DWs act as periodic potentials, yielding fascinating 1D spectral features. Our exploration reveals 1D phenomena localized to Bernal stacking, DW regions, and stacking boundaries, highlighting the intriguing formation of Landau state quantization influenced by the commensuration between the magnetic length and the system. The stable quantized localization within different regions leads to the emergence of unconventional quantized subbands. This study provides valuable insights into the essential properties of stacking-modulated bilayer graphene.
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Affiliation(s)
- Chiun-Yan Lin
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
| | - Da-We Weng
- Department of Physics, National Kaohsiung Normal University, Kaohsiung 82446, Taiwan
| | - Chih-Wei Chiu
- Department of Physics, National Kaohsiung Normal University, Kaohsiung 82446, Taiwan
| | - Godfrey Gumbs
- Department of Physics and Astronomy, Hunter College of the City University of New York, 695 Park Avenue, New York, NY 10065, USA.
- The Graduate School and University Center, The City University of New York, 365 Fifth Avenue, New York, NY 10016, USA
- Donostia International Physics Center (DIPC), P de Manuel Lardizabal, 4, 20018 San Sebastian, Basque Country, Spain
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3
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Chakraborti H, Gorini C, Knothe A, Liu MH, Makk P, Parmentier FD, Perconte D, Richter K, Roulleau P, Sacépé B, Schönenberger C, Yang W. Electron wave and quantum optics in graphene. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:393001. [PMID: 38697131 DOI: 10.1088/1361-648x/ad46bc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Accepted: 05/01/2024] [Indexed: 05/04/2024]
Abstract
In the last decade, graphene has become an exciting platform for electron optical experiments, in some aspects superior to conventional two-dimensional electron gases (2DEGs). A major advantage, besides the ultra-large mobilities, is the fine control over the electrostatics, which gives the possibility of realising gap-less and compact p-n interfaces with high precision. The latter host non-trivial states,e.g., snake states in moderate magnetic fields, and serve as building blocks of complex electron interferometers. Thanks to the Dirac spectrum and its non-trivial Berry phase, the internal (valley and sublattice) degrees of freedom, and the possibility to tailor the band structure using proximity effects, such interferometers open up a completely new playground based on novel device architectures. In this review, we introduce the theoretical background of graphene electron optics, fabrication methods used to realise electron-optical devices, and techniques for corresponding numerical simulations. Based on this, we give a comprehensive review of ballistic transport experiments and simple building blocks of electron optical devices both in single and bilayer graphene, highlighting the novel physics that is brought in compared to conventional 2DEGs. After describing the different magnetic field regimes in graphene p-n junctions and nanostructures, we conclude by discussing the state of the art in graphene-based Mach-Zender and Fabry-Perot interferometers.
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Affiliation(s)
| | - Cosimo Gorini
- Université Paris-Saclay, CEA, CNRS, SPEC, 91191 Gif-sur-Yvette, France
| | - Angelika Knothe
- Institut für Theoretische Physik, Universität Regensburg, D-93040 Regensburg, Germany
| | - Ming-Hao Liu
- Department of Physics and Center for Quantum Frontiers of Research and Technology (QFort), National Cheng Kung University, Tainan 70101, Taiwan
| | - Péter Makk
- Department of Physics, Institute of Physics, Budapest University of Technology and Economics, Műegyetem rkp. 3., Budapest H-1111, Hungary
- MTA-BME Correlated van der Waals Structures Momentum Research Group, Műegyetem rkp. 3., Budapest H-1111, Hungary
| | | | - David Perconte
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000 Grenoble, France
| | - Klaus Richter
- Institut für Theoretische Physik, Universität Regensburg, D-93040 Regensburg, Germany
| | - Preden Roulleau
- Université Paris-Saclay, CEA, CNRS, SPEC, 91191 Gif-sur-Yvette, France
| | - Benjamin Sacépé
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000 Grenoble, France
| | | | - Wenmin Yang
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000 Grenoble, France
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4
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Mondal S, Jayalekshmi UJ, Singh S, Mukherjee RK, Shukla AK. Design, development, and performance of a versatile graphene epitaxy system for the growth of epitaxial graphene on SiC. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2024; 95:063901. [PMID: 38829214 DOI: 10.1063/5.0194852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Accepted: 05/15/2024] [Indexed: 06/05/2024]
Abstract
A versatile graphene epitaxy (GrapE) furnace has been designed and fabricated for the growth of epitaxial graphene (EG) on silicon carbide (SiC) in diverse growth environments ranging from high vacuum to atmospheric argon pressure. Radio-frequency induction enables heating capabilities up to 2000 °C, with controlled heating ramp rates achievable up to 200 °C/s. The details of critical design aspects and temperature characteristics of the GrapE system are discussed. The GrapE system, being automated, has enabled the growth of high-quality EG monolayers and turbostratic EG on SiC using diverse methodologies, such as confinement-controlled sublimation (CCS), open configuration, polymer-assisted CCS, and rapid thermal annealing. This showcases the versatility of the GrapE system in EG growth. Comprehensive characterizations involving atomic force microscopy, Raman spectroscopy, and low-energy electron diffraction techniques were employed to validate the quality of the produced EG.
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Affiliation(s)
- S Mondal
- CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - U J Jayalekshmi
- CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - S Singh
- CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012, India
| | - R K Mukherjee
- CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - A K Shukla
- CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
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Yang D, Laarman JH, Tonouchi M. Sensitive Characterization of the Graphene Transferred onto Varied Si Wafer Surfaces via Terahertz Emission Spectroscopy and Microscopy (TES/LTEM). MATERIALS (BASEL, SWITZERLAND) 2024; 17:1497. [PMID: 38612011 PMCID: PMC11012325 DOI: 10.3390/ma17071497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 03/23/2024] [Accepted: 03/24/2024] [Indexed: 04/14/2024]
Abstract
Graphene shows great potential in developing the next generation of electronic devices. However, the real implementation of graphene-based electronic devices needs to be compatible with existing silicon-based nanofabrication processes. Characterizing the properties of the graphene/silicon interface rapidly and non-invasively is crucial for this endeavor. In this study, we employ terahertz emission spectroscopy and microscopy (TES/LTEM) to evaluate large-scale chemical vapor deposition (CVD) monolayer graphene transferred onto silicon wafers, aiming to assess the dynamic electronic properties of graphene and perform large-scale graphene mapping. By comparing THz emission properties from monolayer graphene on different types of silicon substrates, including those treated with buffered oxide etches, we discern the influence of native oxide layers and surface dipoles on graphene. Finally, the mechanism of THz emission from the graphene/silicon heterojunction is discussed, and the large-scale mapping of monolayer graphene on silicon is achieved successfully. These results demonstrate the efficacy of TES/LTEM for graphene characterization in the modern graphene-based semiconductor industry.
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Affiliation(s)
- Dongxun Yang
- Institute of Laser Engineering, Osaka University, Osaka 565-0871, Japan
| | - Jesse Henri Laarman
- Department of Applied Physics, Eindhoven University of Technology, 5612 AZ Eindhoven, The Netherlands
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Zhao J, Ji P, Li Y, Li R, Zhang K, Tian H, Yu K, Bian B, Hao L, Xiao X, Griffin W, Dudeck N, Moro R, Ma L, de Heer WA. Ultrahigh-mobility semiconducting epitaxial graphene on silicon carbide. Nature 2024; 625:60-65. [PMID: 38172363 DOI: 10.1038/s41586-023-06811-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 10/31/2023] [Indexed: 01/05/2024]
Abstract
Semiconducting graphene plays an important part in graphene nanoelectronics because of the lack of an intrinsic bandgap in graphene1. In the past two decades, attempts to modify the bandgap either by quantum confinement or by chemical functionalization failed to produce viable semiconducting graphene. Here we demonstrate that semiconducting epigraphene (SEG) on single-crystal silicon carbide substrates has a band gap of 0.6 eV and room temperature mobilities exceeding 5,000 cm2 V-1 s-1, which is 10 times larger than that of silicon and 20 times larger than that of the other two-dimensional semiconductors. It is well known that when silicon evaporates from silicon carbide crystal surfaces, the carbon-rich surface crystallizes to produce graphene multilayers2. The first graphitic layer to form on the silicon-terminated face of SiC is an insulating epigraphene layer that is partially covalently bonded to the SiC surface3. Spectroscopic measurements of this buffer layer4 demonstrated semiconducting signatures4, but the mobilities of this layer were limited because of disorder5. Here we demonstrate a quasi-equilibrium annealing method that produces SEG (that is, a well-ordered buffer layer) on macroscopic atomically flat terraces. The SEG lattice is aligned with the SiC substrate. It is chemically, mechanically and thermally robust and can be patterned and seamlessly connected to semimetallic epigraphene using conventional semiconductor fabrication techniques. These essential properties make SEG suitable for nanoelectronics.
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Affiliation(s)
- Jian Zhao
- Tianjin International Center for Nanoparticles and Nanosystems, Tianjin University, Tianjin, People's Republic of China
| | - Peixuan Ji
- Tianjin International Center for Nanoparticles and Nanosystems, Tianjin University, Tianjin, People's Republic of China
| | - Yaqi Li
- Tianjin International Center for Nanoparticles and Nanosystems, Tianjin University, Tianjin, People's Republic of China
| | - Rui Li
- Tianjin International Center for Nanoparticles and Nanosystems, Tianjin University, Tianjin, People's Republic of China
| | - Kaimin Zhang
- Tianjin International Center for Nanoparticles and Nanosystems, Tianjin University, Tianjin, People's Republic of China
| | - Hao Tian
- Tianjin International Center for Nanoparticles and Nanosystems, Tianjin University, Tianjin, People's Republic of China
| | - Kaicheng Yu
- Tianjin International Center for Nanoparticles and Nanosystems, Tianjin University, Tianjin, People's Republic of China
| | - Boyue Bian
- Tianjin International Center for Nanoparticles and Nanosystems, Tianjin University, Tianjin, People's Republic of China
| | - Luzhen Hao
- Tianjin International Center for Nanoparticles and Nanosystems, Tianjin University, Tianjin, People's Republic of China
| | - Xue Xiao
- Tianjin International Center for Nanoparticles and Nanosystems, Tianjin University, Tianjin, People's Republic of China
| | - Will Griffin
- School of Physics, Georgia Institute of Technology, Atlanta, GA, USA
| | - Noel Dudeck
- School of Physics, Georgia Institute of Technology, Atlanta, GA, USA
| | - Ramiro Moro
- Tianjin International Center for Nanoparticles and Nanosystems, Tianjin University, Tianjin, People's Republic of China
| | - Lei Ma
- Tianjin International Center for Nanoparticles and Nanosystems, Tianjin University, Tianjin, People's Republic of China.
| | - Walt A de Heer
- Tianjin International Center for Nanoparticles and Nanosystems, Tianjin University, Tianjin, People's Republic of China.
- School of Physics, Georgia Institute of Technology, Atlanta, GA, USA.
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