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Duan Y, Xu W, Kong W, Wang J, Zhang J, Yang Z, Cai Q. Modification on Flower Defects and Electronic Properties of Epitaxial Graphene by Erbium. ACS OMEGA 2023; 8:37600-37609. [PMID: 37841144 PMCID: PMC10568997 DOI: 10.1021/acsomega.3c06523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 09/15/2023] [Indexed: 10/17/2023]
Abstract
Manipulating the topological defects and electronic properties of graphene has been a subject of great interest. In this work, we have investigated the influence of Er predeposition on flower defects and electronic band structures of epitaxial graphene on SiC. It is shown that Er atoms grown on the SiC substrate actually work as an activator to induce flower defect formation with a density of 1.52 × 1012 cm-2 during the graphitization process when the Er coverage is 1.6 ML, about 5 times as much as that of pristine graphene. First-principles calculations demonstrate that Er greatly decreases the formation energy of the flower defect. We have discussed Er promoting effects on flower defect formation as well as its formation mechanism. Scanning tunneling microscopy (STM) and Raman and X-ray photoelectron spectroscopy (XPS) have been utilized to reveal the Er doping effect and its modification to electronic structures of graphene. N-doping enhancement and band gap opening can be observed by using angle-resolved photoemission spectroscopy (ARPES). With Er coverage increasing from 0 to 1.6 ML, the Dirac point energy decreases from -0.34 to -0.37 eV and the band gap gradually increases from 320 to 360 meV. The opening of the band gap is attributed to the synergistic effect of substitution doping of Er atoms and high-density flower defects.
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Affiliation(s)
- Yong Duan
- State Key Laboratory of Surface
Physics and Department of Physics, Fudan
University, Shanghai 200433, People’s
Republic of China
| | - Wenting Xu
- State Key Laboratory of Surface
Physics and Department of Physics, Fudan
University, Shanghai 200433, People’s
Republic of China
| | - Wenxia Kong
- State Key Laboratory of Surface
Physics and Department of Physics, Fudan
University, Shanghai 200433, People’s
Republic of China
| | - Jianxin Wang
- State Key Laboratory of Surface
Physics and Department of Physics, Fudan
University, Shanghai 200433, People’s
Republic of China
| | - Jinzhe Zhang
- State Key Laboratory of Surface
Physics and Department of Physics, Fudan
University, Shanghai 200433, People’s
Republic of China
| | - Zhongqin Yang
- State Key Laboratory of Surface
Physics and Department of Physics, Fudan
University, Shanghai 200433, People’s
Republic of China
| | - Qun Cai
- State Key Laboratory of Surface
Physics and Department of Physics, Fudan
University, Shanghai 200433, People’s
Republic of China
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Masson L, Prévot G. Epitaxial growth and structural properties of silicene and other 2D allotropes of Si. NANOSCALE ADVANCES 2023; 5:1574-1599. [PMID: 36926561 PMCID: PMC10012843 DOI: 10.1039/d2na00808d] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 02/13/2023] [Indexed: 06/18/2023]
Abstract
Since the breakthrough of graphene, considerable efforts have been made to search for two-dimensional (2D) materials composed of other group 14 elements, in particular silicon and germanium, due to their valence electronic configuration similar to that of carbon and their widespread use in the semiconductor industry. Silicene, the silicon counterpart of graphene, has been particularly studied, both theoretically and experimentally. Theoretical studies were the first to predict a low-buckled honeycomb structure for free-standing silicene possessing most of the outstanding electronic properties of graphene. From an experimental point of view, as no layered structure analogous to graphite exists for silicon, the synthesis of silicene requires the development of alternative methods to exfoliation. Epitaxial growth of silicon on various substrates has been widely exploited in attempts to form 2D Si honeycomb structures. In this article, we provide a comprehensive state-of-the-art review focusing on the different epitaxial systems reported in the literature, some of which having generated controversy and long debates. In the search for the synthesis of 2D Si honeycomb structures, other 2D allotropes of Si have been discovered and will also be presented in this review. Finally, with a view to applications, we discuss the reactivity and air-stability of silicene as well as the strategy devised to decouple epitaxial silicene from the underlying surface and its transfer to a target substrate.
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Affiliation(s)
| | - Geoffroy Prévot
- Sorbonne Université, CNRS, Institut des NanoSciences de Paris, INSP F-75005 Paris France
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Shan G, Tan H, Ma R, Zhao H, Huang W. Recent progress in emergent two-dimensional silicene. NANOSCALE 2023; 15:2982-2996. [PMID: 36655560 DOI: 10.1039/d2nr05809j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Although graphene is by far the most famous example of two-dimensional (2D) materials, which exhibits a wealth of exotic and intriguing properties, it suffers from a severe drawback. In this regard, the exploration of silicene, the silicon analog of the graphene material, has attracted substantial interest in the past decade. This review therefore provides a comprehensive survey of recent theoretical and experimental works on this 2D material. We first overview the distinctive structures and properties of silicene, including mechanical, electronic, and spintronic properties. We then discuss the growth and experimental characterization of silicene on Ag(111) and other different substrates, providing insights into the different phases or atomic arrangements of silicene observed on the metallic surfaces as well as on its electronic structures. Then, the recent state-of-the-art applications of silicene are summarized in section 4 with the aim to break the scientific and engineering barriers for application in nanoelectronics, sensors, energy storage devices, electrode materials, and quantum technology. Finally, the concluding remarks and the future prospects of silicene are also provided.
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Affiliation(s)
- Guangcun Shan
- School of Instrumentation Science and Opto-electronic Engineering, Beihang University, No. 37 XueYuan Road, Beijing 100083, China.
- Institute of Experimental Physics, Saarland University, 66123 Saarbrücken, Germany
| | - Haoyi Tan
- School of Instrumentation Science and Opto-electronic Engineering, Beihang University, No. 37 XueYuan Road, Beijing 100083, China.
| | - Ruguang Ma
- School of Materials Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, China
| | - Hongbin Zhao
- State Key Laboratory of Advanced Materials for Smart Sensing, General Research Institute for Nonferrous Metals, Beijing 100088, China.
| | - Wei Huang
- Frontiers Science Center for Flexible Electronics, Xi'an Institute of Flexible Electronics (IFE) and Xi'an Institute of Biomedical Materials & Engineering, Northwestern Polytechnical University, Xi'an 710072, China
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Jiménez GC, Morinson-Negrete JD, Blanquicett FP, Ortega-López C, Espitia-Rico MJ. Effects of Mono-Vacancies and Co-Vacancies of Nitrogen and Boron on the Energetics and Electronic Properties of Heterobilayer h-BN/graphene. MATERIALS (BASEL, SWITZERLAND) 2022; 15:6369. [PMID: 36143681 PMCID: PMC9505817 DOI: 10.3390/ma15186369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 08/30/2022] [Accepted: 09/05/2022] [Indexed: 06/16/2023]
Abstract
A study is carried out which investigates the effects of the mono-vacancies of boron (VB) and nitrogen (VN) and the co-vacancies of nitrogen (N), and boron (B) on the energetics and the structural, electronic, and magnetic properties of an h-BN/graphene heterobilayer using first-principles calculations within the framework of the density functional theory (DFT). The heterobilayer is modelled using the periodic slab scheme. In the present case, a 4 × 4-(h-BN) monolayer is coupled to a 4 × 4-graphene monolayer, with a mismatch of 1.40%. In this coupling, the surface of interest is the 4 × 4-(h-BN) monolayer; the 4 × 4-graphene only represents the substrate that supports the 4 × 4-(h-BN) monolayer. From the calculations of the energy of formation of the 4 × 4-(h-BN)/4 × 4-graphene heterobilayer, with and without defects, it is established that, in both cases, the heterobilayers are energetically stable, from which it is inferred that these heterobilayers can be grown in the experiment. The formation of a mono-vacancy of boron (1 VB), a mono-vacancy of nitrogen (1 VN), and co-vacancies of boron and nitrogen (VBN) induce, on the structural level: (a) for 1 VB, a contraction n of the B-N bond lengths of ~2.46% and a slight change in the interfacial distance D (~0.096%) with respect to the heterobilayer free of defects (FD) are observed; (b) for 1 VN, a slight contraction of the B-N of bond lengths of ~0.67% and an approach between the h-BN monolayer and the graphene of ~3.83% with respect to the FD heterobilayer are observed; (c) for VBN, it can be seen that the N-N and B-B bond lengths (in the 1 VB and 1 VN regions, respectively) undergo an increase of ~2.00% and a decrease of ~3.83%, respectively. The calculations of the Löwdin charge for the FD heterobilayer and for those with defects (1 VB, 1 VN, and VBN) show that the inclusion of this type of defect induces significant changes in the Löwdin charge redistribution of the neighboring atoms of VB and VN, causing chemically active regions that could favor the interaction of the heterobilayer with external atoms and/or molecules. On the basis of an analysis of the densities of states and the band structures, it is established that the heterobilayer with 1 VB and VBN take on a half-metallic and magnetic behavior. Due to all of these properties, the FD heterobilayer and those with 1 VB, 1 VN, and VBN are candidates for possible adsorbent materials and possible materials that could be used for different spintronic applications.
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Affiliation(s)
- Gladys Casiano Jiménez
- Grupo Avanzado de Materiales y Sistemas Complejos GAMASCO, Universidad de Córdoba, Montería CP 230001, Colombia
- Doctorado en Ciencias Física, Universidad de Córdoba, Montería CP 2030001, Colombia
| | - Juan David Morinson-Negrete
- Grupo Avanzado de Materiales y Sistemas Complejos GAMASCO, Universidad de Córdoba, Montería CP 230001, Colombia
- Grupo de Investigación AMDAC, Institución Educativa José María Córdoba, Montería CP 2300001, Colombia
| | | | - César Ortega-López
- Grupo Avanzado de Materiales y Sistemas Complejos GAMASCO, Universidad de Córdoba, Montería CP 230001, Colombia
- Doctorado en Ciencias Física, Universidad de Córdoba, Montería CP 2030001, Colombia
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Ben Jabra Z, Abel M, Fabbri F, Aqua JN, Koudia M, Michon A, Castrucci P, Ronda A, Vach H, De Crescenzi M, Berbezier I. Van der Waals Heteroepitaxy of Air-Stable Quasi-Free-Standing Silicene Layers on CVD Epitaxial Graphene/6H-SiC. ACS NANO 2022; 16:5920-5931. [PMID: 35294163 DOI: 10.1021/acsnano.1c11122] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Graphene, consisting of an inert, thermally stable material with an atomically flat, dangling-bond-free surface, is by essence an ideal template layer for van der Waals heteroepitaxy of two-dimensional materials such as silicene. However, depending on the synthesis method and growth parameters, graphene (Gr) substrates could exhibit, on a single sample, various surface structures, thicknesses, defects, and step heights. These structures noticeably affect the growth mode of epitaxial layers, e.g., turning the layer-by-layer growth into the Volmer-Weber growth promoted by defect-assisted nucleation. In this work, the growth of silicon on chemical vapor deposited epitaxial Gr (1 ML Gr/1 ML Gr buffer) on a 6H-SiC(0001) substrate is investigated by a combination of atomic force microscopy (AFM), scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and Raman spectroscopy measurements. It is shown that the perfect control of full-scale almost defect-free 1 ML Gr with a single surface structure and the ultraclean conditions for molecular beam epitaxy deposition of silicon represent key prerequisites for ensuring the growth of extended silicene sheets on epitaxial graphene. At low coverages, the deposition of Si produces large silicene sheets (some hundreds of nanometers large) attested by both AFM and SEM observations and the onset of a Raman peak at 560 cm-1, very close to the theoretical value of 570 cm-1 calculated for free-standing silicene. This vibrational mode at 560 cm-1 represents the highest ever experimentally measured value and is representative of quasi-free-standing silicene with almost no interaction with inert nonmetal substrates. From a coverage rate of 1 ML, the silicene sheets disappear at the expense of 3D Si dendritic islands whose density, size, and thickness increase with the deposited thickness. From this coverage, the Raman mode assigned to quasi-free-standing silicene totally vanishes, and the 2D flakes of silicene are no longer observed by AFM. The experimental results are in very good agreement with the results of kinetic Monte Carlo simulations that rationalize the initial flake growth in solid-state dewetting conditions, followed by the growth of ridges surrounding and eventually covering the 2D flakes. A full description of the growth mechanism is given. This study, which covers a wide range of growth parameters, challenges recent results stating the impossibility to grow silicene on a carbon inert surface and is very promising for large-scale silicene growth. It shows that silicene growth can be achieved using perfectly controlled and ultraclean deposition conditions and an almost defect-free Gr substrate.
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Affiliation(s)
| | - Mathieu Abel
- Aix Marseille University, CNRS, IM2NP, Marseille 13397, France
| | - Filippo Fabbri
- NEST, Istituto Nanoscienze-CNR, Scuola Normale Superiore, Piazza San Silvestro 12, 56127 Pisa, Italy
| | - Jean-Noel Aqua
- Institut des Nanosciences de Paris, Sorbonne Université, CNRS, INSP, UMR 7588, 75005 Paris, France
| | - Mathieu Koudia
- Aix Marseille University, CNRS, IM2NP, Marseille 13397, France
| | - Adrien Michon
- Université Côte d'Azur, CNRS, CRHEA, Valbonne 06560, France
| | - Paola Castrucci
- Dipartimento di Fisica, Università di Roma Tor Vergata, Roma 00133, Italy
| | - Antoine Ronda
- Aix Marseille University, CNRS, IM2NP, Marseille 13397, France
| | - Holger Vach
- LPICM, CNRS, Ecole Polytechnique, IP Paris, Palaiseau 91128, France
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Bao L, Huang L, Guo H, Gao HJ. Construction and physical properties of low-dimensional structures for nanoscale electronic devices. Phys Chem Chem Phys 2022; 24:9082-9117. [PMID: 35383791 DOI: 10.1039/d1cp05981e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Over the past decades, construction of nanoscale electronic devices with novel functionalities based on low-dimensional structures, such as single molecules and two-dimensional (2D) materials, has been rapidly developed. To investigate their intrinsic properties for versatile functionalities of nanoscale electronic devices, it is crucial to precisely control the structures and understand the physical properties of low-dimensional structures at the single atomic level. In this review, we provide a comprehensive overview of the construction of nanoelectronic devices based on single molecules and 2D materials and the investigation of their physical properties. For single molecules, we focus on the construction of single-molecule devices, such as molecular motors and molecular switches, by precisely controlling their self-assembled structures on metal substrates and charge transport properties. For 2D materials, we emphasize their spin-related electrical transport properties for spintronic device applications and the role that interfaces among 2D semiconductors, contact electrodes, and dielectric substrates play in the electrical performance of electronic, optoelectronic, and memory devices. Finally, we discuss the future research direction in this field, where we can expect a scientific breakthrough.
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Affiliation(s)
- Lihong Bao
- Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, P. R. China. .,Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, P. R. China
| | - Li Huang
- Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, P. R. China.
| | - Hui Guo
- Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, P. R. China.
| | - Hong-Jun Gao
- Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, P. R. China. .,Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, P. R. China
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7
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High-Quality Graphene-Based Tunable Absorber Based on Double-Side Coupled-Cavity Effect. NANOMATERIALS 2021; 11:nano11112824. [PMID: 34835589 PMCID: PMC8624350 DOI: 10.3390/nano11112824] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 10/18/2021] [Accepted: 10/20/2021] [Indexed: 11/16/2022]
Abstract
Graphene-based devices have important applications attributed to their superior performance and flexible tunability in practice. In this paper, a new kind of absorber with monolayer graphene sandwiched between two layers of dielectric rings is proposed. Two peaks with almost complete absorption are realized. The mechanism is that the double-layer dielectric rings added to both sides of the graphene layer are equivalent to resonators, whose double-side coupled-cavity effect can make the incident electromagnetic wave highly localized in the upper and lower surfaces of graphene layer simultaneously, leading to significant enhancement in the absorption of graphene. Furthermore, the influence of geometrical parameters on absorption performance is investigated in detail. Also, the device can be actively manipulated after fabrication through varying the chemical potential of graphene. As a result, the frequency shifts of the two absorption peaks can reach as large as 2.82 THz/eV and 3.83 THz/eV, respectively. Such a device could be used as tunable absorbers and other functional devices, such as multichannel filters, chemical/biochemical modulators and sensors.
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Zhou X, Yu G. Preparation Engineering of Two-Dimensional Heterostructures via Bottom-Up Growth for Device Applications. ACS NANO 2021; 15:11040-11065. [PMID: 34264631 DOI: 10.1021/acsnano.1c02985] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Two-dimensional heterostructures with tremendous electronic and optoelectronic properties hold great promise for nanodevice integrations and applications owing to the wide tunable characteristics. Toward this end, developing construction strategies in allusion to large-scale production of high-quality heterostructures is critical. The mainstream preparation routes are representatively classified into two categories of top-down and bottom-up approaches. Nonetheless, the relatively low reproductivity and the limitation for lateral heterostructure formations of top-down methods at the present stage inherently impeded their further developments. To surmount these obstacles, assembling heterostructures via miscellaneous bottom-up preparation protocols has emerged as a potential solution, attributed to the controllability and clean interface. Three typical approaches of chemical/physical vapor deposition, solution synthesis, and growth under ultrahigh vacuum conditions have shown promise due to the possibilities for preparing heterostructures with predesigned structures, clean interfaces, and the like. Therefore, bottom-up preparation engineering of heterostructures in two dimensions for further device applications is of vital importance. Moreover, heterostructure integrations by these methods have experienced a period of flourishing development in the past few years. In this review, the classical bottom-up growth routes, characterization methods, and latest progress of diverse heterostructures and further device applications are overviewed. Finally, the challenges and opportunities are discussed.
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Affiliation(s)
- Xiahong Zhou
- Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P.R. China
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, P.R. China
| | - Gui Yu
- Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P.R. China
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, P.R. China
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Cao Q, Grote F, Huβmann M, Eigler S. Emerging field of few-layered intercalated 2D materials. NANOSCALE ADVANCES 2021; 3:963-982. [PMID: 36133283 PMCID: PMC9417328 DOI: 10.1039/d0na00987c] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 12/31/2020] [Indexed: 06/13/2023]
Abstract
The chemistry and physics of intercalated layered 2D materials (2DMs) are the focus of this review article. Special attention is given to intercalated bilayer and few-layer systems. Thereby, intercalated few-layers of graphene and transition metal dichalcogenides play the major role; however, also other intercalated 2DMs develop fascinating properties with thinning down. Here, we briefly introduce the historical background of intercalation and explain concepts, which become relevent with intercalating few-layers. Then, we describe various synthetic methods to yield intercalated 2DMs and focus next on current research directions, which are superconductivity, band gap tuning, magnetism, optical properties, energy storage and chemical reactions. We focus on major breakthroughs in all introduced sections and give an outlook to this emerging field of research.
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Affiliation(s)
- Qing Cao
- Institute of Chemistry and Biochemistry, Freie Universität Berlin Takustraβe 3 14195 Berlin Germany
| | - Fabian Grote
- Institute of Chemistry and Biochemistry, Freie Universität Berlin Takustraβe 3 14195 Berlin Germany
| | - Marleen Huβmann
- Institute of Chemistry and Biochemistry, Freie Universität Berlin Takustraβe 3 14195 Berlin Germany
| | - Siegfried Eigler
- Institute of Chemistry and Biochemistry, Freie Universität Berlin Takustraβe 3 14195 Berlin Germany
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