1
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Wang C, Wang K, Wang H, Tian Q, Zong J, Qiu X, Ren W, Wang L, Li FS, Zhang WB, Zhang H, Zhang Y. Observation of a Folded Dirac Cone in Heavily Doped Graphene. J Phys Chem Lett 2023; 14:7149-7156. [PMID: 37540032 DOI: 10.1021/acs.jpclett.3c01271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/05/2023]
Abstract
Superlattice potentials imposed on graphene can alter its Dirac states, enabling the realization of various quantum phases. We report the experimental observation of a replica Dirac cone at the Brillouin zone center induced by a superlattice in heavily doped graphene with Gd intercalation using angle-resolved photoemission spectroscopy (ARPES). The replica Dirac cone arises from the (√3× √3)R30° superlattice formed by the intervalley coupling of two nonequivalent valleys (e.g., the Kekulé-like distortion phase), accompanied by a bandgap opening. According to the findings, the replica Dirac band in Gd-intercalated graphene disappears beyond a critical temperature of 30 K and can be suppressed by potassium adsorption. The modulation of the replica Dirac band is primarily attributable to the residual frozen gas, which can act as a source of intervalley scattering at temperatures below 30 K. Our results highlight the persistence of the hidden Kekulé-like phase within the heavily doped graphene, enriching our current understanding of its replica Dirac Fermions.
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Affiliation(s)
- Can Wang
- Hunan Provincial Key Laboratory of Flexible Electronic Materials Genome Engineering, School of Physics and Electronic Sciences, Changsha University of Science and Technology, Changsha 410114, China
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Kaili Wang
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing 210093, China
| | - Huaiqiang Wang
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing 210093, China
| | - Qichao Tian
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing 210093, China
| | - Junyu Zong
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing 210093, China
| | - Xiaodong Qiu
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing 210093, China
| | - Wei Ren
- Vacuum Interconnected Nanotech Workstation (Nano-X), Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences (CAS), Suzhou 215123, China
| | - Li Wang
- Vacuum Interconnected Nanotech Workstation (Nano-X), Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences (CAS), Suzhou 215123, China
| | - Fang-Sen Li
- Vacuum Interconnected Nanotech Workstation (Nano-X), Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences (CAS), Suzhou 215123, China
| | - Wei-Bing Zhang
- Hunan Provincial Key Laboratory of Flexible Electronic Materials Genome Engineering, School of Physics and Electronic Sciences, Changsha University of Science and Technology, Changsha 410114, China
| | - Haijun Zhang
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Yi Zhang
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
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Li X, Yang J, Sun H, Huang L, Li H, Shi J. Controlled Synthesis and Accurate Doping of Wafer-Scale 2D Semiconducting Transition Metal Dichalcogenides. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023:e2305115. [PMID: 37406665 DOI: 10.1002/adma.202305115] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 06/24/2023] [Accepted: 07/04/2023] [Indexed: 07/07/2023]
Abstract
2D semiconducting transition metal dichalcogenide (TMDCs) possess atomically thin thickness, a dangling-bond-free surface, flexible band structure, and silicon-compatible feature, making them one of the most promising channels for constructing state-of-the-art field-effect transistors in the post-Moore's era. However, the existing 2D semiconducting TMDCs fall short of meeting the industry criteria for practical applications in electronics due to their small domain size and the lack of an effective approach to modulate intrinsic physical properties. Therefore, it is crucial to prepare and dope 2D semiconducting TMDCs single crystals with wafer size. In this review, the up-to-date progress regarding the wafer-scale growth of 2D semiconducting TMDC polycrystalline and single-crystal films is systematically summarized. The domain orientation control of 2D TMDCs and the seamless stitching of unidirectionally aligned 2D islands by means of substrate design are proposed. In addition, the accurate and uniform doping of 2D semiconducting TMDCs and the effect on electronic device performances are also discussed. Finally, the dominating challenges pertaining to the enhancement of the electronic device performances of TMDCs are emphasized, and further development directions are put forward. This review provides a systematic and in-depth summary of high-performance device applications of 2D semiconducting TMDCs.
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Affiliation(s)
- Xiaohui Li
- The Institute for Advanced Studies, Wuhan University, Wuhan, 430072, P. R. China
| | - Junbo Yang
- The Institute for Advanced Studies, Wuhan University, Wuhan, 430072, P. R. China
| | - Hang Sun
- The Institute for Advanced Studies, Wuhan University, Wuhan, 430072, P. R. China
| | - Ling Huang
- The Institute for Advanced Studies, Wuhan University, Wuhan, 430072, P. R. China
| | - Hui Li
- The Institute for Advanced Studies, Wuhan University, Wuhan, 430072, P. R. China
| | - Jianping Shi
- The Institute for Advanced Studies, Wuhan University, Wuhan, 430072, P. R. China
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3
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Yu M, Hu Z, Zhou J, Lu Y, Guo W, Zhang Z. Retrieving Grain Boundaries in 2D Materials. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2205593. [PMID: 36461686 DOI: 10.1002/smll.202205593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 11/13/2022] [Indexed: 06/17/2023]
Abstract
The coalescence of randomly distributed grains with different crystallographic orientations can result in pervasive grain boundaries (GBs) in 2D materials during their chemical synthesis. GBs not only are the inherent structural imperfection that causes influential impacts on structures and properties of 2D materials, but also have emerged as a platform for exploring unusual physics and functionalities stemming from dramatic changes in local atomic organization and even chemical makeup. Here, recent advances in studying the formation mechanism, atomic structures, and functional properties of GBs in a range of 2D materials are reviewed. By analyzing the growth mechanism and the competition between far-field strain and local chemical energies of dislocation cores, a complete understanding of the rich GB morphologies as well as their dependence on lattice misorientations and chemical compositions is presented. Mechanical, electronic, and chemical properties tied to GBs in different materials are then discussed, towards raising the concept of using GBs as a robust atomic-scale scaffold for realizing tailored functionalities, such as magnetism, luminescence, and catalysis. Finally, the future opportunities in retrieving GBs for making functional devices and the major challenges in the controlled formation of GB structures for designed applications are commented.
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Affiliation(s)
- Maolin Yu
- Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control of Mechanical Structures, and Institute for Frontier Science, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China
| | - Zhili Hu
- Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control of Mechanical Structures, and Institute for Frontier Science, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China
| | - Jingzhuo Zhou
- Department of Mechanical Engineering, City University of Hong Kong, Kowloon, Hong Kong SAR, 999077, China
| | - Yang Lu
- Department of Mechanical Engineering, City University of Hong Kong, Kowloon, Hong Kong SAR, 999077, China
| | - Wanlin Guo
- Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control of Mechanical Structures, and Institute for Frontier Science, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China
| | - Zhuhua Zhang
- Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control of Mechanical Structures, and Institute for Frontier Science, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China
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4
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Gollavelli G, Gedda G, Mohan R, Ling YC. Status Quo on Graphene Electrode Catalysts for Improved Oxygen Reduction and Evolution Reactions in Li-Air Batteries. Molecules 2022; 27:molecules27227851. [PMID: 36431956 PMCID: PMC9692502 DOI: 10.3390/molecules27227851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 11/01/2022] [Accepted: 11/07/2022] [Indexed: 11/16/2022] Open
Abstract
Reduced global warming is the goal of carbon neutrality. Therefore, batteries are considered to be the best alternatives to current fossil fuels and an icon of the emerging energy industry. Voltaic cells are one of the power sources more frequently employed than photovoltaic cells in vehicles, consumer electronics, energy storage systems, and medical equipment. The most adaptable voltaic cells are lithium-ion batteries, which have the potential to meet the eagerly anticipated demands of the power sector. Working to increase their power generating and storage capability is therefore a challenging area of scientific focus. Apart from typical Li-ion batteries, Li-Air (Li-O2) batteries are expected to produce high theoretical power densities (3505 W h kg-1), which are ten times greater than that of Li-ion batteries (387 W h kg-1). On the other hand, there are many challenges to reaching their maximum power capacity. Due to the oxygen reduction reaction (ORR) and oxygen evolution reaction (OES), the cathode usually faces many problems. Designing robust structured catalytic electrode materials and optimizing the electrolytes to improve their ability is highly challenging. Graphene is a 2D material with a stable hexagonal carbon network with high surface area, electrical, thermal conductivity, and flexibility with excellent chemical stability that could be a robust electrode material for Li-O2 batteries. In this review, we covered graphene-based Li-O2 batteries along with their existing problems and updated advantages, with conclusions and future perspectives.
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Affiliation(s)
- Ganesh Gollavelli
- Department of Humanities and Basic Sciences, Aditya Engineering College, Surampalem, Jawaharlal Nehru Technological University Kakinada, Kakinada 533437, India
| | - Gangaraju Gedda
- Department of Chemistry, Presidency University, Banglore 560064, India
| | - Raja Mohan
- Department of Chemistry, Presidency University, Banglore 560064, India
| | - Yong-Chien Ling
- Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan
- Correspondence:
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Krasavin SE, Osipov VA. Electrical resistivity of polycrystalline graphene: effect of grain-boundary-induced strain fields. Sci Rep 2022; 12:14553. [PMID: 36008503 PMCID: PMC9411566 DOI: 10.1038/s41598-022-18604-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 08/16/2022] [Indexed: 11/10/2022] Open
Abstract
We have revealed the decisive role of grain-boundary-induced strain fields in electron scattering in polycrystalline graphene. To this end, we have formulated the model based on Boltzmann transport theory which properly takes into account the microscopic structure of grain boundaries (GB) as a repeated sequence of heptagon–pentagon pairs. We show that at naturally low GB charges the strain field scattering dominates and leads to physically reasonable and, what is important, experimentally observable values of the electrical resistivity. It ranges from 0.1 to 10 k\documentclass[12pt]{minimal}
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\begin{document}$$\upmu$$\end{document}μm and has a strong dependence on misorientation angle. For low-angle highly charged GBs, two scattering mechanisms may compete. The resistivity increases markedly with decreasing GB size and reaches values of 60 k\documentclass[12pt]{minimal}
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\begin{document}$$\upmu$$\end{document}μm and more. It is also very sensitive to the presence of irregularities modeled by embedding of partial disclination dipoles. With significant distortion, we found an increase in resistance by more than an order of magnitude, which is directly related to the destruction of diffraction on the GB. Our findings may be of interest both in the interpretation of experimental data and in the design of electronic devices based on poly- and nanocrystalline graphene.
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Affiliation(s)
- S E Krasavin
- Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Dubna, Moscow Region, Russia, 141980.
| | - V A Osipov
- Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Dubna, Moscow Region, Russia, 141980
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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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Huang SD, Chu ED, Wang YH, Liou JW, Wang RS, Woon WY, Chiu HC. Variations in the Effective Work Function of Graphene in a Sliding Electrical Contact Interface under Ambient Conditions. ACS APPLIED MATERIALS & INTERFACES 2022; 14:27328-27338. [PMID: 35438951 DOI: 10.1021/acsami.2c02096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Control of work function (WF) in graphene is crucial for graphene application in electrode material replacement and electrode surface protection in optoelectronic devices. Although efforts have been made to manipulate the effective WF of graphene to optimize its application, most studies have focused on graphene employed in static electrical contact interfaces. In this work, we investigated WF variations of supported single-layer graphene (SLG) in sliding electrical contact under ambient conditions, which was achieved by sliding an electrically biased conductive atomic force microscopy (cAFM) probe on the SLG surface. The effective WF, structural properties, and chemical compositions of rubbed SLG were subsequently measured by Kelvin probe force microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy, respectively. We found that the effective WF of the rubbed SLG was governed by both the tunneling triboelectric effect (TTE) and tribochemical-induced surface functionalization. The TTE charges generated by the sliding cAFM probe tunneled through the structural defects of the SLG and were trapped underneath the SLG. The SLG will be either p-doped or n-doped depending on the type of TTE charges and the polarity of electric bias applied to the cAFM probe during the rubbing process. However, the applied electric bias also led to the electrolysis of a water meniscus formed at the cAFM probe-SLG contact, resulting in surface oxidation and the increase of SLG WF. Further absorption of ambient water molecules on the oxygenated functional groups gradually reduced the SLG WF. The influence of TTE and surface functionalization on the SLG WF depends on the magnitude and polarity of applied electric biases, relative humidity, and physical properties of the supporting substrates. Our results demonstrate that the effective WF of SLG in a sliding electrical contact interface will vary with time and might need to be considered for related applications.
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Affiliation(s)
- Shuei-De Huang
- Department of Physics, National Taiwan Normal University, Taipei 11677, Taiwan
| | - En-De Chu
- Department of Physics, National Taiwan Normal University, Taipei 11677, Taiwan
| | - Yu-Han Wang
- Molecular Science and Technology Program, Taiwan International Graduate Program, Institute of Atomic and Molecular Science, Academia Sinica, Taipei 10617, Taiwan
- Department of Physics, National Central University, Taoyuan 32001, Taiwan
| | - Jhe-Wei Liou
- Molecular Science and Technology Program, Taiwan International Graduate Program, Institute of Atomic and Molecular Science, Academia Sinica, Taipei 10617, Taiwan
| | - Ruei-Si Wang
- Department of Physics, National Taiwan Normal University, Taipei 11677, Taiwan
| | - Wei-Yen Woon
- Molecular Science and Technology Program, Taiwan International Graduate Program, Institute of Atomic and Molecular Science, Academia Sinica, Taipei 10617, Taiwan
- Department of Physics, National Central University, Taoyuan 32001, Taiwan
| | - Hsiang-Chih Chiu
- Department of Physics, National Taiwan Normal University, Taipei 11677, Taiwan
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8
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Unconventional Metallicity in Graphene Nanoribbons with Armchair Edges. ADVANCED THEORY AND SIMULATIONS 2022. [DOI: 10.1002/adts.202100392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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9
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Majee AK, Aksamija Z. Electronic transport across extended grain boundaries in graphene. NANO EXPRESS 2021. [DOI: 10.1088/2632-959x/ac0597] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Abstract
Owing to its superlative carrier mobility and atomic thinness, graphene exhibits great promise for interconnects in future nanoelectronic integrated circuits. Chemical vapor deposition (CVD), the most popular method for wafer-scale growth of graphene, produces monolayers that are polycrystalline, where misoriented grains are separated by extended grain boundaries (GBs). Theoretical models of GB resistivity focused on small sections of an extended GB, assuming it to be a straight line, and predicted a strong dependence of resistivity on misorientation angle. In contrast, measurements produced values in a much narrower range and without a pronounced angle dependence. Here we study electron transport across rough GBs, which are composed of short straight segments connected together into an extended GB. We found that, due to the zig-zag nature of rough GBs, there always exist a few segments that divide the crystallographic angle between two grains symmetrically and provide a highly conductive path for the current to flow across the GBs. The presence of highly conductive segments produces resistivity between 102 to 104 Ω μm regardless of misorientation angle. An extended GB with large roughness and small correlation length has small resistivity on the order of 103 Ω μm, even for highly mismatched asymmetric GBs. The effective slope of the GB, given by the ratio of roughness and lateral correlation length, is an effective universal quantifier for GB resistivity. Our results demonstrate that the probability of finding conductive segments diminishes in short GBs, which could cause a large variation in the resistivity of narrow ribbons etched from polycrystalline graphene. We also uncover spreading resistance due to the current bending in the grains to flow through the conductive segments of the GB and show that it scales linearly with the grain resistance. Our results will be crucial for designing graphene-based interconnects for future integrated circuits.
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10
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Hsieh K, Kochat V, Biswas T, Tiwary CS, Mishra A, Ramalingam G, Jayaraman A, Chattopadhyay K, Raghavan S, Jain M, Ghosh A. Spontaneous Time-Reversal Symmetry Breaking at Individual Grain Boundaries in Graphene. PHYSICAL REVIEW LETTERS 2021; 126:206803. [PMID: 34110182 DOI: 10.1103/physrevlett.126.206803] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 03/30/2021] [Indexed: 06/12/2023]
Abstract
Graphene grain boundaries (GBs) have attracted interest for their ability to host nearly dispersionless electronic bands and magnetic instabilities. Here, we employ quantum transport and universal conductance fluctuation measurements to experimentally demonstrate a spontaneous breaking of time-reversal symmetry across individual GBs of chemical vapor deposited graphene. While quantum transport across the GBs indicate spin-scattering-induced dephasing and hence formation of local magnetic moments, below T≲4 K we observe complete lifting of time-reversal symmetry at high carrier densities (n≳5×10^{12} cm^{-2}) and low temperature (T≲2 K). An unprecedented thirtyfold reduction in the universal conductance fluctuation magnitude with increasing doping density further supports the possibility of an emergent frozen magnetic state at the GBs. Our experimental results suggest that realistic GBs of graphene can be a promising resource for new electronic phases and spin-based applications.
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Affiliation(s)
- Kimberly Hsieh
- Department of Physics, Indian Institute of Science, Bangalore 560 012, India
| | - Vidya Kochat
- Department of Physics, Indian Institute of Science, Bangalore 560 012, India
| | - Tathagata Biswas
- Department of Physics, Indian Institute of Science, Bangalore 560 012, India
| | - Chandra Sekhar Tiwary
- Department of Materials Engineering, Indian Institute of Science, Bangalore 560 012, India
| | - Abhishek Mishra
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore 560 012, India
| | | | - Aditya Jayaraman
- Department of Physics, Indian Institute of Science, Bangalore 560 012, India
| | - Kamanio Chattopadhyay
- Department of Materials Engineering, Indian Institute of Science, Bangalore 560 012, India
| | - Srinivasan Raghavan
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore 560 012, India
- Materials Research Center, Indian Institute of Science, Bangalore 560 012, India
| | - Manish Jain
- Department of Physics, Indian Institute of Science, Bangalore 560 012, India
| | - Arindam Ghosh
- Department of Physics, Indian Institute of Science, Bangalore 560 012, India
- Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore 560 012, India
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11
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Pandhi T, Cornwell C, Fujimoto K, Barnes P, Cox J, Xiong H, Davis PH, Subbaraman H, Koehne JE, Estrada D. Fully inkjet-printed multilayered graphene-based flexible electrodes for repeatable electrochemical response. RSC Adv 2020; 10:38205-38219. [PMID: 35517530 PMCID: PMC9057201 DOI: 10.1039/d0ra04786d] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 10/09/2020] [Indexed: 12/30/2022] Open
Abstract
Graphene has proven to be useful in biosensing applications. However, one of the main hurdles with printed graphene-based electrodes is achieving repeatable electrochemical performance from one printed electrode to another. We have developed a consistent fabrication process to control the sheet resistance of inkjet-printed graphene electrodes, thereby accomplishing repeatable electrochemical performance. Herein, we investigated the electrochemical properties of multilayered graphene (MLG) electrodes fully inkjet-printed (IJP) on flexible Kapton substrates. The electrodes were fabricated by inkjet printing three materials – (1) a conductive silver ink for electrical contact, (2) an insulating dielectric ink, and (3) MLG ink as the sensing material. The selected materials and fabrication methods provided great control over the ink rheology and material deposition, which enabled stable and repeatable electrochemical response: bending tests revealed the electrochemical behavior of these sensors remained consistent over 1000 bend cycles. Due to the abundance of structural defects (e.g., edge defects) present in the exfoliated graphene platelets, cyclic voltammetry (CV) of the graphene electrodes showed good electron transfer (k = 1.125 × 10−2 cm s−1) with a detection limit (0.01 mM) for the ferric/ferrocyanide redox couple, [Fe(CN)6]−3/−4, which is comparable or superior to modified graphene or graphene oxide-based sensors. Additionally, the potentiometric response of the electrodes displayed good sensitivity over the pH range of 4–10. Moreover, a fully IJP three-electrode device (MLG, platinum, and Ag/AgCl) also showed quasi-reversibility compared to a single IJP MLG electrode device. These findings demonstrate significant promise for scalable fabrication of a flexible, low cost, and fully-IJP wearable sensor system needed for space, military, and commercial biosensing applications. A fully inkjet printed and flexible multilayer graphene based three electrode device showed electrochemical reversibility.![]()
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Affiliation(s)
- Twinkle Pandhi
- Micron School of Materials Science and Engineering, Boise State University Boise ID 83725-2090 USA
| | - Casey Cornwell
- Department of Chemistry, Northwest Nazarene University Nampa ID 83686 USA
| | - Kiyo Fujimoto
- Micron School of Materials Science and Engineering, Boise State University Boise ID 83725-2090 USA
| | - Pete Barnes
- Micron School of Materials Science and Engineering, Boise State University Boise ID 83725-2090 USA
| | - Jasmine Cox
- Department of Electrical and Computer Engineering, Boise State University Boise ID 83725-2075 USA
| | - Hui Xiong
- Micron School of Materials Science and Engineering, Boise State University Boise ID 83725-2090 USA
| | - Paul H Davis
- Micron School of Materials Science and Engineering, Boise State University Boise ID 83725-2090 USA
| | - Harish Subbaraman
- Department of Electrical and Computer Engineering, Boise State University Boise ID 83725-2075 USA
| | | | - David Estrada
- Micron School of Materials Science and Engineering, Boise State University Boise ID 83725-2090 USA .,Center for Advanced Energy Studies, Boise State University Boise ID 83725-1012 USA
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Abstract
Grain boundaries (GBs) are a kind of lattice imperfection widely existing in two-dimensional materials, playing a critical role in materials' properties and device performance. Related key issues in this area have drawn much attention and are still under intense investigation. These issues include the characterization of GBs at different length scales, the dynamic formation of GBs during the synthesis, the manipulation of the configuration and density of GBs for specific material functionality, and the understanding of structure-property relationships and device applications. This review will provide a general introduction of progress in this field. Several techniques for characterizing GBs, such as direct imaging by high-resolution transmission electron microscopy, visualization techniques of GBs by optical microscopy, plasmon propagation, or second harmonic generation, are presented. To understand the dynamic formation process of GBs during the growth, a general geometric approach and theoretical consideration are reviewed. Moreover, strategies controlling the density of GBs for GB-free materials or materials with tunable GB patterns are summarized, and the effects of GBs on materials' properties are discussed. Finally, challenges and outlook are provided.
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Affiliation(s)
- Wenqian Yao
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Science, Beijing 100190, P.R. China
- Sino-Danish Center for Education and Research, Sino-Danish College, University of Chinese Academy of Sciences, Beijing 100049, P.R. China
| | - Bin Wu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Science, Beijing 100190, P.R. China
| | - Yunqi Liu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Science, Beijing 100190, P.R. China
- Sino-Danish Center for Education and Research, Sino-Danish College, University of Chinese Academy of Sciences, Beijing 100049, P.R. China
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13
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Computational Atomistic Modeling in Carbon Flatland and Other 2D Nanomaterials. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10051724] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
As in many countries, the rise of nanosciences in Belgium has been triggered in the eighties in the one hand, by the development of scanning tunneling and atomic force microscopes offering an unprecedented possibility to visualize and manipulate the atoms, and in the other hand, by the synthesis of nano-objects in particular carbon nanostructures such as fullerene and nanotubes. Concomitantly, the increasing calculating power and the emergence of computing facilities together with the development of DFT-based ab initio softwares have brought to nanosciences field powerful simulation tools to analyse and predict properties of nano-objects. Starting with 0D and 1D nanostructures, the floor is now occupied by the 2D materials with graphene being the bow of this 2D ship. In this review article, some specific examples of 2D systems has been chosen to illustrate how not only density functional theory (DFT) but also tight-binding (TB) techniques can be daily used to investigate theoretically the electronic, phononic, magnetic, and transport properties of these atomically thin layered materials.
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14
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Cummings AW, Dubois SMM, Charlier JC, Roche S. Universal Spin Diffusion Length in Polycrystalline Graphene. NANO LETTERS 2019; 19:7418-7426. [PMID: 31532994 DOI: 10.1021/acs.nanolett.9b03112] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Graphene grown by chemical vapor deposition (CVD) is the most promising material for industrial-scale applications based on graphene monolayers. It also holds promise for spintronics; despite being polycrystalline, spin transport in CVD graphene has been measured over lengths up to 30 μm, which is on par with the best measurements made in single-crystal graphene. These results suggest that grain boundaries (GBs) in CVD graphene, while impeding charge transport, may have little effect on spin transport. However, to date very little is known about the true impact of disordered networks of GBs on spin relaxation. Here, by using first-principles simulations, we derive an effective tight-binding model of graphene GBs in the presence of spin-orbit coupling (SOC), which we then use to evaluate spin transport in realistic morphologies of polycrystalline graphene. The spin diffusion length is found to be independent of the grain size, and it is determined only by the strength of the substrate-induced SOC. This result is consistent with the D'yakonov-Perel' mechanism of spin relaxation in the diffusive regime, but we find that it also holds in the presence of quantum interference. These results clarify the role played by GBs and demonstrate that the average grain size does not dictate the upper limit for spin transport in CVD-grown graphene, a result of fundamental importance for optimizing large-scale graphene-based spintronic devices.
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Affiliation(s)
- Aron W Cummings
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST , Campus UAB, Bellaterra , 08193 Barcelona , Spain
| | - Simon M-M Dubois
- Institute of Condensed Matter and Nanosciences , Université catholique de Louvain , B-1348 Louvain-la-Neuve , Belgium
| | - Jean-Christophe Charlier
- Institute of Condensed Matter and Nanosciences , Université catholique de Louvain , B-1348 Louvain-la-Neuve , Belgium
| | - Stephan Roche
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST , Campus UAB, Bellaterra , 08193 Barcelona , Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats , 08010 Barcelona , Spain
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15
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Cho JH, Na SR, Park S, Akinwande D, Liechti KM, Cullinan MA. Controlling the number of layers in graphene using the growth pressure. NANOTECHNOLOGY 2019; 30:235602. [PMID: 30780133 DOI: 10.1088/1361-6528/ab0847] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Monolayer graphene is commonly grown on Cu substrates due to the self-limiting nature of graphene synthesis by chemical vapor deposition (CVD). Consequently, the growth of multilayer graphene by CVD has proven to be relatively difficult. This study demonstrates that the number of layers in graphene synthesized on a copper substrate can be precisely set by controlling the partial pressure of hydrogen gas used in the CVD process. This study also shows that a pressure threshold exists for a distinct transition from monolayer to multilayer graphene growth. This threshold is shown to be the boundary where the graphene growth process on Cu by CVD is no longer a self-limiting process. In addition, the multilayer graphene synthesized through the pressure control method forms in the Volmer-Weber mode with an AB stacking structure.
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Affiliation(s)
- Joon Hyong Cho
- Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX 78712, United States of America
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16
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Effect of graphene substrate type on formation of Bi 2Se 3 nanoplates. Sci Rep 2019; 9:4791. [PMID: 30886194 PMCID: PMC6423328 DOI: 10.1038/s41598-019-41178-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 02/14/2019] [Indexed: 11/15/2022] Open
Abstract
Knowledge of nucleation and further growth of Bi2Se3 nanoplates on different substrates is crucial for obtaining ultrathin nanostructures and films of this material by physical vapour deposition technique. In this work, Bi2Se3 nanoplates were deposited under the same experimental conditions on different types of graphene substrates (as-transferred and post-annealed chemical vapour deposition grown monolayer graphene, monolayer graphene grown on silicon carbide substrate). Dimensions of the nanoplates deposited on graphene substrates were compared with the dimensions of the nanoplates deposited on mechanically exfoliated mica and highly ordered pyrolytic graphite flakes used as reference substrates. The influence of different graphene substrates on nucleation and further lateral and vertical growth of the Bi2Se3 nanoplates is analysed. Possibility to obtain ultrathin Bi2Se3 thin films on these substrates is evaluated. Between the substrates considered in this work, graphene grown on silicon carbide is found to be the most promising substrate for obtaining of 1–5 nm thick Bi2Se3 films.
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17
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Zhang S, Gao L, Song A, Zheng X, Yao Q, Ma T, Di Z, Feng XQ, Li Q. Tuning Local Electrical Conductivity via Fine Atomic Scale Structures of Two-Dimensional Interfaces. NANO LETTERS 2018; 18:6030-6036. [PMID: 30165022 DOI: 10.1021/acs.nanolett.8b02921] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Two-dimensional (2D) materials have seen a broad range of applications in electronic and optoelectronic applications; however, full realization of this potential hitherto largely hinges on the quality and performance of the electrical contacts formed between 2D materials and their surrounding metals/semiconductors. Despite the progress in revealing the charge injecting mechanisms and enhancing electrical conductance using various interfacial treatments, how the microstructure of contact interfaces affects local electrical conductivity is still very limited. Here, using conductive atomic force microscopy (c-AFM), for the first time, we directly confirm the conjecture that the electrical conductivity of physisorbed 2D material-metal/semiconductor interfaces is determined by the local electronic charge transfer. Using lattice-resolved conductivity mapping and first-principles calculations, we demonstrate that the electronic charge transfer, thereby electrical conductivity, can be fine-tuned by the topological defects of 2D materials and the atomic stacking with respect to the substrate. Our finding provides a novel route to engineer the electrical contact properties by exploiting fine atomic interactions; in the meantime, it also suggests a convenient and nondestructive means of probing subtle interactions along 2D heterogeneous interfaces.
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Affiliation(s)
- Shuai Zhang
- AML, Center for Nano and Micro Mechanics, Department of Engineering Mechanics , Tsinghua University , Beijing 100084 , China
- State Key Laboratory of Tribology , Tsinghua University , Beijing 100084 , China
| | - Lei Gao
- State Key Laboratory of Tribology , Tsinghua University , Beijing 100084 , China
- Corrosion and Protection Center, Key Laboratory for Environmental Fracture (MOE) , University of Science and Technology Beijing , Beijing 100083 , China
| | - Aisheng Song
- State Key Laboratory of Tribology , Tsinghua University , Beijing 100084 , China
| | - Xiaohu Zheng
- State Key Laboratory of Functional Materials for Informatics , Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences , Shanghai 200050 , China
| | - Quanzhou Yao
- AML, Center for Nano and Micro Mechanics, Department of Engineering Mechanics , Tsinghua University , Beijing 100084 , China
| | - Tianbao Ma
- State Key Laboratory of Tribology , Tsinghua University , Beijing 100084 , China
| | - Zengfeng Di
- State Key Laboratory of Functional Materials for Informatics , Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences , Shanghai 200050 , China
| | - Xi-Qiao Feng
- AML, Center for Nano and Micro Mechanics, Department of Engineering Mechanics , Tsinghua University , Beijing 100084 , China
- State Key Laboratory of Tribology , Tsinghua University , Beijing 100084 , China
| | - Qunyang Li
- AML, Center for Nano and Micro Mechanics, Department of Engineering Mechanics , Tsinghua University , Beijing 100084 , China
- State Key Laboratory of Tribology , Tsinghua University , Beijing 100084 , China
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18
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Dechamps S, Nguyen VH, Charlier JC. Ab initio quantum transport in polycrystalline graphene. NANOSCALE 2018; 10:7759-7768. [PMID: 29658557 DOI: 10.1039/c8nr00289d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Synthesis techniques such as chemical vapor deposition yield graphene in polycrystalline flakes where single-crystal domains are separated by grain boundaries (GBs) of irregular shape. These structural defects are mostly made up of pentagon-heptagon pairs and represent an important source of scattering, thus strongly affecting electronic mobilities in polycrystalline graphene (PG). In the present article, first-principles simulations are performed to explore charge transport through a GB in PG using the Landauer-Büttiker formalism implemented within the Green's function approach. In ideal GB configurations, electronic transport is found to depend on their topology as already suggested in the literature. However, more realistic GBs constructed out of various carbon rings and with more complex periodicities are also considered, possibly inducing leakage currents. Finally, additional realistic disorder such as vacancies, a larger inter-connectivity region and out-of plane buckling is investigated. For specific energies, charge redistribution effects related to the detailed GB topology are found to substantially alter the transmissions. Altogether, the transport gap is predicted to be inversely proportional to the smallest significant periodic pattern and nearly independent of the interface configuration.
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Affiliation(s)
- Samuel Dechamps
- Institute of Condensed Matter and Nanosciences, Université catholique de Louvain, Chemin des étoiles 8, B-1348 Louvain-la-Neuve, Belgium.
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19
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Huang KC, McCall J, Wang P, Liao CS, Eakins G, Cheng JX, Yang C. High-Speed Spectroscopic Transient Absorption Imaging of Defects in Graphene. NANO LETTERS 2018; 18:1489-1497. [PMID: 29342361 DOI: 10.1021/acs.nanolett.7b05283] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Graphene grain boundaries (GBs) and other nanodefects can deteriorate electronic properties. Here, using transient absorption (TA) microscopy we directly visualized GBs by TA intensity increase due to change in density of state. We also observed a faster decay due to defect-accelerated carrier relaxation in the GB area. By line-illumination and parallel detection, we increased the TA intensity imaging speed to 1000 frames per second, which is 6 orders of magnitude faster than Raman microscopy. Combined with a resonant optical delay tuner which scans a 5.3 ps temporal delay within 92 μs, our system enabled spectroscopic TA imaging, at a speed of 50 stacks per second, to probe and characterize graphene nanodefects based on the TA decay rate. Finally, we demonstrate real-time nondestructive characterization of graphene at a rolling speed of 0.3 m/min, which matches the fastest roll-to-roll manufacturing process reported.
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Affiliation(s)
- Kai-Chih Huang
- Department of Biomedical Engineering, Boston University , Boston, Massachusetts 02215, United States
| | - Jeremy McCall
- Department of Chemistry, Purdue University , West Lafayette, Indiana 47907, United States
| | - Pu Wang
- School of Biological Science and Medical Engineering, Beihang University , Beijing 100083, China
- Beijing Advanced Innovation Centre for Biomedical Engineering, Beihang University , Beijing 102402, China
| | - Chien-Sheng Liao
- Department of Biomedical Engineering, Boston University , Boston, Massachusetts 02215, United States
| | - Gregory Eakins
- Jonathan Amy Facility for Chemical Instrumentation, Purdue University , West Lafayette, Indiana 47907, United States
| | - Ji-Xin Cheng
- Department of Biomedical Engineering, Boston University , Boston, Massachusetts 02215, United States
- Department of Electrical and Computer Engineering, Boston University , Boston, Massachusetts 02215, United States
| | - Chen Yang
- Department of Electrical and Computer Engineering, Boston University , Boston, Massachusetts 02215, United States
- Department of Chemistry, Boston University , Boston, Massachusetts 02215, United States
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20
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Ma J, Li X, Yin L, Wang W, Sun Q, Yang Y, Zhang P, Nie J, Xiong C, Dou R. Mapping electronic states of triple anti-parallel and symmetric zigzag grain boundaries of graphene on highly oriented pyrolytic graphite. Chem Phys Lett 2018. [DOI: 10.1016/j.cplett.2017.12.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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21
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Impact of Mismatch Angle on Electronic Transport Across Grain Boundaries and Interfaces in 2D Materials. Sci Rep 2017; 7:16597. [PMID: 29185483 PMCID: PMC5707417 DOI: 10.1038/s41598-017-16744-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 11/15/2017] [Indexed: 11/09/2022] Open
Abstract
We study the impact of grain boundaries (GB) and misorientation angles between grains on electronic transport in 2-dimensional materials. Here we have developed a numerical model based on the first-principles electronic bandstructure calculations in conjunction with a method which computes electron transmission coefficients from simultaneous conservation of energy and momentum at the interface to essentially evaluate GB/interface resistance in a Landauer formalism. We find that the resistance across graphene GBs vary over a wide range depending on misorientation angles and type of GBs, starting from 53 Ω μm for low-mismatch angles in twin (symmetric) GBs to about 1020 Ω μm for 21° mismatch in tilt (asymmetric) GBs. On the other hand, misorientation angles have weak influence on the resistance across MoS2 GBs, ranging from about 130 Ω μm for low mismatch angles to about 6000 Ω μm for 21°. The interface resistance across graphene-MoS2 heterojunctions also exhibits a strong dependence on misorientation angles with resistance values ranging from about 100 Ω μm for low-mismatch angles in Class-I (symmetric) interfaces to 1015 Ω μm for 14° mismatch in Class-II (asymmetric) interfaces. Overall, symmetric homo/heterojunctions exhibit a weak dependence on misorientation angles, while in MoS2 both symmetric and asymmetric GBs show a gradual dependence on mismatch angles.
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22
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Ma R, Huan Q, Wu L, Yan J, Guo W, Zhang YY, Wang S, Bao L, Liu Y, Du S, Pantelides ST, Gao HJ. Direct Four-Probe Measurement of Grain-Boundary Resistivity and Mobility in Millimeter-Sized Graphene. NANO LETTERS 2017; 17:5291-5296. [PMID: 28786680 DOI: 10.1021/acs.nanolett.7b01624] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Grain boundaries (GBs) in polycrystalline graphene scatter charge carriers, which reduces carrier mobility and limits graphene applications in high-speed electronics. Here we report the extraction of the resistivity of GBs and the effect of GBs on carrier mobility by direct four-probe measurements on millimeter-sized graphene bicrystals grown by chemical vapor deposition (CVD). To extract the GB resistivity and carrier mobility from direct four-probe intragrain and intergrain measurements, an electronically equivalent extended 2D GB region is defined based on Ohm's law. Measurements on seven representative GBs find that the maximum resistivities are in the range of several kΩ·μm to more than 100 kΩ·μm. Furthermore, the mobility in these defective regions is reduced to 0.4-5.9‰ of the mobility of single-crystal, pristine graphene. Similarly, the effect of wrinkles on carrier transport can also be derived. The present approach provides a reliable way to directly probe charge-carrier scattering at GBs and can be further applied to evaluate the GB effect of other two-dimensional polycrystalline materials, such as transition-metal dichalcogenides (TMDCs).
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Affiliation(s)
- Ruisong Ma
- Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences , P.O. Box 603, Beijing 100190, People's Republic of China
- Beijing Key Laboratory for Nanomaterials and Nanodevices , Beijing 100190, People's Republic of China
| | - Qing Huan
- Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences , P.O. Box 603, Beijing 100190, People's Republic of China
| | - Liangmei Wu
- Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences , P.O. Box 603, Beijing 100190, People's Republic of China
- Beijing Key Laboratory for Nanomaterials and Nanodevices , Beijing 100190, People's Republic of China
| | - Jiahao Yan
- Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences , P.O. Box 603, Beijing 100190, People's Republic of China
- Beijing Key Laboratory for Nanomaterials and Nanodevices , Beijing 100190, People's Republic of China
| | - Wei Guo
- School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology , Wuhan 430074, People's Republic of China
| | - Yu-Yang Zhang
- Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences , P.O. Box 603, Beijing 100190, People's Republic of China
| | - Shuai Wang
- School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology , Wuhan 430074, People's Republic of China
| | - Lihong Bao
- Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences , P.O. Box 603, Beijing 100190, People's Republic of China
- Beijing Key Laboratory for Nanomaterials and Nanodevices , Beijing 100190, People's Republic of China
| | - Yunqi Liu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Science , Beijing 100190, People's Republic of China
| | - Shixuan Du
- Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences , P.O. Box 603, Beijing 100190, People's Republic of China
- Beijing Key Laboratory for Nanomaterials and Nanodevices , Beijing 100190, People's Republic of China
| | - Sokrates T Pantelides
- Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences , P.O. Box 603, Beijing 100190, People's Republic of China
- Department of Physics and Astronomy and Department of Electrical Engineering and Computer Science, Vanderbilt University , Nashville, Tennessee 37235, United States
| | - Hong-Jun Gao
- Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences , P.O. Box 603, Beijing 100190, People's Republic of China
- Beijing Key Laboratory for Nanomaterials and Nanodevices , Beijing 100190, People's Republic of China
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23
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Thodkar K, Thompson D, Lüönd F, Moser L, Overney F, Marot L, Schönenberger C, Jeanneret B, Calame M. Restoring the Electrical Properties of CVD Graphene via Physisorption of Molecular Adsorbates. ACS APPLIED MATERIALS & INTERFACES 2017; 9:25014-25022. [PMID: 28675296 DOI: 10.1021/acsami.7b05143] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Chemical vapor deposition (CVD) is a powerful technique to produce graphene for large-scale applications. Polymer-assisted wet transfer is commonly used to move the graphene onto silicon substrates, but the resulting devices tend to exhibit p-doping, which decreases the device quality and reproducibility. In an effort to better understand the origin of this effect, we coated graphene with n-methyl-2-pyrrolidone (NMP) and hexamethyldisilazane (HMDS) molecules that exhibit negligible charge transfer to graphene but bind more strongly to graphene than ambient adsorbents. Using Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), electrical transport measurements, and quantum mechanical computer simulations, we show that the molecules help in the removal of p-doping, and our data indicate that the molecules do this by replacing ambient adsorbents (typically O2 and water) on the graphene surface. This very simple method of improving the electronic properties of CVD graphene by passivating its surface with common solvent molecules will accelerate the development of CVD graphene-based devices.
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Affiliation(s)
- Kishan Thodkar
- Empa, Swiss Federal Laboratories for Materials Science and Technology , Überlandstrasse 129, Dübendorf CH-8600, Switzerland
| | - Damien Thompson
- Department of Physics, Bernal Institute, University of Limerick , Limerick V94 T9PX, Ireland
| | - Felix Lüönd
- Federal Institute of Metrology , Lindenweg 50, Bern-Wabern 3003, Switzerland
| | | | - Frédéric Overney
- Federal Institute of Metrology , Lindenweg 50, Bern-Wabern 3003, Switzerland
| | | | | | - Blaise Jeanneret
- Federal Institute of Metrology , Lindenweg 50, Bern-Wabern 3003, Switzerland
| | - Michel Calame
- Empa, Swiss Federal Laboratories for Materials Science and Technology , Überlandstrasse 129, Dübendorf CH-8600, Switzerland
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24
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Kim S, Kim TY, Lee KH, Kim TH, Cimini FA, Kim SK, Hinchet R, Kim SW, Falconi C. Rewritable ghost floating gates by tunnelling triboelectrification for two-dimensional electronics. Nat Commun 2017. [PMID: 28649986 PMCID: PMC5490184 DOI: 10.1038/ncomms15891] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Gates can electrostatically control charges inside two-dimensional materials. However, integrating independent gates typically requires depositing and patterning suitable insulators and conductors. Moreover, after manufacturing, gates are unchangeable. Here we introduce tunnelling triboelectrification for localizing electric charges in very close proximity of two-dimensional materials. As representative materials, we use chemical vapour deposition graphene deposited on a SiO2/Si substrate. The triboelectric charges, generated by friction with a Pt-coated atomic force microscope tip and injected through defects, are trapped at the air–SiO2 interface underneath graphene and act as ghost floating gates. Tunnelling triboelectrification uniquely permits to create, modify and destroy p and n regions at will with the spatial resolution of atomic force microscopes. As a proof of concept, we draw rewritable p/n+ and p/p+ junctions with resolutions as small as 200 nm. Our results open the way to time-variant two-dimensional electronics where conductors, p and n regions can be defined on demand. Once fabricated, the gates of conventional electronic devices are spatially fixed. Here, the authors introduce tunnelling triboelectrification to create, modify and destroy on-demand ghost floating gates underneath 2D materials, with the spatial resolution of an atomic force microscope.
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Affiliation(s)
- Seongsu Kim
- School of Advanced Materials Science and Engineering, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 440-746, Republic of Korea
| | - Tae Yun Kim
- SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University (SKKU), Suwon 440-746, Republic of Korea
| | - Kang Hyuck Lee
- School of Advanced Materials Science and Engineering, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 440-746, Republic of Korea
| | - Tae-Ho Kim
- School of Advanced Materials Science and Engineering, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 440-746, Republic of Korea
| | - Francesco Arturo Cimini
- Department of Electronic Engineering, University of Rome Tor Vergata, Via del Politecnico 1, Roma 00133, Italy
| | - Sung Kyun Kim
- School of Advanced Materials Science and Engineering, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 440-746, Republic of Korea
| | - Ronan Hinchet
- School of Advanced Materials Science and Engineering, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 440-746, Republic of Korea
| | - Sang-Woo Kim
- School of Advanced Materials Science and Engineering, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 440-746, Republic of Korea.,SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University (SKKU), Suwon 440-746, Republic of Korea
| | - Christian Falconi
- Department of Electronic Engineering, University of Rome Tor Vergata, Via del Politecnico 1, Roma 00133, Italy
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25
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Park KD, Raschke MB, Atkin JM, Lee YH, Jeong MS. Probing Bilayer Grain Boundaries in Large-Area Graphene with Tip-Enhanced Raman Spectroscopy. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1603601. [PMID: 27935201 DOI: 10.1002/adma.201603601] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 10/04/2016] [Indexed: 06/06/2023]
Abstract
The bilayer grain boundaries (GBs) in chemical-vapor-deposition-grown large-area graphene are identified using multispectral tip-enhanced Raman imaging with 18 nm spatial resolution. The misorientation angle of the bilayer GBs is determined from a quantitative analysis of the phonon-scattering properties associated with the modified electronic structure.
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Affiliation(s)
- Kyoung-Duck Park
- Department of Physics, Department of Chemistry, and JILA, University of Colorado, Boulder, CO, 80309, USA
| | - Markus B Raschke
- Department of Physics, Department of Chemistry, and JILA, University of Colorado, Boulder, CO, 80309, USA
| | - Joanna M Atkin
- Department of Chemistry, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Young Hee Lee
- Center for Integrated Nanostructure Physics, Institute for Basic Science, Sungkyunkwan University, Suwon, 440-746, Republic of Korea
- Department of Energy Science, Sungkyunkwan University, Suwon, 440-746, Republic of Korea
| | - Mun Seok Jeong
- Center for Integrated Nanostructure Physics, Institute for Basic Science, Sungkyunkwan University, Suwon, 440-746, Republic of Korea
- Department of Energy Science, Sungkyunkwan University, Suwon, 440-746, Republic of Korea
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26
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Komissarov IV, Kovalchuk NG, Labunov VA, Girel KV, Korolik OV, Tivanov MS, Lazauskas A, Andrulevičius M, Tamulevičius T, Grigaliūnas V, Meškinis Š, Tamulevičius S, Prischepa SL. Nitrogen-doped twisted graphene grown on copper by atmospheric pressure CVD from a decane precursor. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2017; 8:145-158. [PMID: 28243551 PMCID: PMC5301970 DOI: 10.3762/bjnano.8.15] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 12/12/2016] [Indexed: 06/06/2023]
Abstract
We present Raman studies of graphene films grown on copper foil by atmospheric pressure CVD with n-decane as a precursor, a mixture of nitrogen and hydrogen as the carrier gas, under different hydrogen flow rates. A novel approach for the processing of the Raman spectroscopy data was employed. It was found that in particular cases, the various parameters of the Raman spectra can be assigned to fractions of the films with different thicknesses. In particular, such quantities as the full width at half maximum of the 2D peak and the position of the 2D graphene band were successfully applied for the elaborated approach. Both the G- and 2D-band positions of single layer fractions were blue-shifted, which could be associated with the nitrogen doping of studied films. The XPS study revealed the characteristics of incorporated nitrogen, which was found to have a binding energy around 402 eV. Moreover, based on the statistical analysis of spectral parameters and the observation of a G-resonance, the twisted nature of the double-layer fraction of graphene grown with a lower hydrogen feeding rate was demonstrated. The impact of the varied hydrogen flow rate on the structural properties of graphene and the nitrogen concentration is also discussed.
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Affiliation(s)
- Ivan V Komissarov
- Belarusian State University of Informatics and Radioelectronics, P. Brovka str. 6, Minsk 220013, Belarus
| | - Nikolai G Kovalchuk
- Belarusian State University of Informatics and Radioelectronics, P. Brovka str. 6, Minsk 220013, Belarus
| | - Vladimir A Labunov
- Belarusian State University of Informatics and Radioelectronics, P. Brovka str. 6, Minsk 220013, Belarus
| | - Ksenia V Girel
- Belarusian State University of Informatics and Radioelectronics, P. Brovka str. 6, Minsk 220013, Belarus
| | - Olga V Korolik
- Belarusian State University, Nezavisimosti av. 4, Minsk 220030, Belarus
| | - Mikhail S Tivanov
- Belarusian State University, Nezavisimosti av. 4, Minsk 220030, Belarus
| | - Algirdas Lazauskas
- Institute of Materials Science, Kaunas University of Technology, K. Baršausko str. 59, Kaunas 51423, Lithuania
| | - Mindaugas Andrulevičius
- Institute of Materials Science, Kaunas University of Technology, K. Baršausko str. 59, Kaunas 51423, Lithuania
| | - Tomas Tamulevičius
- Institute of Materials Science, Kaunas University of Technology, K. Baršausko str. 59, Kaunas 51423, Lithuania
| | - Viktoras Grigaliūnas
- Institute of Materials Science, Kaunas University of Technology, K. Baršausko str. 59, Kaunas 51423, Lithuania
| | - Šarunas Meškinis
- Institute of Materials Science, Kaunas University of Technology, K. Baršausko str. 59, Kaunas 51423, Lithuania
| | - Sigitas Tamulevičius
- Institute of Materials Science, Kaunas University of Technology, K. Baršausko str. 59, Kaunas 51423, Lithuania
| | - Serghej L Prischepa
- Belarusian State University of Informatics and Radioelectronics, P. Brovka str. 6, Minsk 220013, Belarus
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27
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Conductance fluctuations in high mobility monolayer graphene: Nonergodicity, lack of determinism and chaotic behavior. Sci Rep 2016; 6:33118. [PMID: 27609184 PMCID: PMC5016828 DOI: 10.1038/srep33118] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 08/19/2016] [Indexed: 11/20/2022] Open
Abstract
We have fabricated a high mobility device, composed of a monolayer graphene flake sandwiched between two sheets of hexagonal boron nitride. Conductance fluctuations as functions of a back gate voltage and magnetic field were obtained to check for ergodicity. Non-linear dynamics concepts were used to study the nature of these fluctuations. The distribution of eigenvalues was estimated from the conductance fluctuations with Gaussian kernels and it indicates that the carrier motion is chaotic at low temperatures. We argue that a two-phase dynamical fluid model best describes the transport in this system and can be used to explain the violation of the so-called ergodic hypothesis found in graphene.
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28
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Zhou X, Qi Y, Shi J, Niu J, Liu M, Zhang G, Li Q, Zhang Z, Hong M, Ji Q, Zhang Y, Liu Z, Wu X, Zhang Y. Modulating the Electronic Properties of Monolayer Graphene Using a Periodic Quasi-One-Dimensional Potential Generated by Hex-Reconstructed Au(001). ACS NANO 2016; 10:7550-7557. [PMID: 27478993 DOI: 10.1021/acsnano.6b02548] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The structural and electronic properties of monolayer graphene synthesized on a periodically reconstructed substrate can be widely modulated by the generation of superstructure patterns, thereby producing interesting physical properties, such as magnetism and superconductivity. Herein, using a facile chemical vapor deposition method, we successfully synthesized high-quality monolayer graphene with a uniform thickness on Au foils. The hex-reconstruction of Au(001), which is characterized by striped patterns with a periodicity of 1.44 nm, promoted the formation of a quasi-one-dimensional (1D) graphene superlattice, which served as a periodic quasi-1D modulator for the graphene overlayer, as evidenced by scanning tunneling microscopy/spectroscopy. Intriguingly, two new Dirac points were generated for the quasi-1D graphene superlattice located at -1.73 ± 0.02 and 1.12 ± 0.12 eV. Briefly, this work demonstrates that the periodic modulation effect of reconstructed metal substrates can dramatically alter the electronic properties of graphene and provides insight into the modulation of these properties using 1D potentials.
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Affiliation(s)
| | | | | | - Jingjing Niu
- Collaborative Innovation Center of Quantum Matter , Beijing 100871, People's Republic of China
| | | | - Guanhua Zhang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences , Dalian 116023, People's Republic of China
| | | | | | | | | | | | | | - Xiaosong Wu
- Collaborative Innovation Center of Quantum Matter , Beijing 100871, People's Republic of China
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29
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Long F, Yasaei P, Sanoj R, Yao W, Král P, Salehi-Khojin A, Shahbazian-Yassar R. Characteristic Work Function Variations of Graphene Line Defects. ACS APPLIED MATERIALS & INTERFACES 2016; 8:18360-18366. [PMID: 27356179 DOI: 10.1021/acsami.6b04853] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Line defects, including grain boundaries and wrinkles, are commonly seen in graphene grown by chemical vapor deposition. These one-dimensional defects are believed to alter the electrical and mechanical properties of graphene. Unfortunately, it is very tedious to directly distinguish grain boundaries from wrinkles due to their similar morphologies. In this report, high-resolution Kelvin potential force microscopy (KPFM) is employed to measure the work function distribution of graphene line defects. The characteristic work function variations of grain boundaries, standing-collapsed wrinkles, and folded wrinkles could be clearly identified. Classical and quantum molecular dynamics simulations reveal that the unique work function distribution of each type of line defects is originated from the doping effect induced by the SiO2 substrate. Our results suggest that KPFM can be an easy-to-use and accurate method to detect graphene line defects, and also propose the possibility to tune the graphene work function by defect engineering.
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Affiliation(s)
- Fei Long
- Department of Mechanical Engineering and Engineering Mechanics, Michigan Technological University , Houghton, Michigan 49931, United States
| | | | | | - Wentao Yao
- Department of Mechanical Engineering and Engineering Mechanics, Michigan Technological University , Houghton, Michigan 49931, United States
| | | | | | - Reza Shahbazian-Yassar
- Department of Mechanical Engineering and Engineering Mechanics, Michigan Technological University , Houghton, Michigan 49931, United States
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30
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Hong JY, Shin YC, Zubair A, Mao Y, Palacios T, Dresselhaus MS, Kim SH, Kong J. A Rational Strategy for Graphene Transfer on Substrates with Rough Features. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2016; 28:2382-92. [PMID: 26808866 DOI: 10.1002/adma.201505527] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 12/02/2015] [Indexed: 05/23/2023]
Abstract
Graphene grown by chemical vapor deposition is transferred by a very simple, yet effective approach from the growth substrate onto substrates with rough features. This novel and facile method not only results in satisfactory transfer on substrates with terraces or grooves, but also gives rise to a successful result for uneven growth substrates.
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Affiliation(s)
- Jin-Yong Hong
- Department of Electrical Engineeringand Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
| | - Yong Cheol Shin
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
| | - Ahmad Zubair
- Department of Electrical Engineeringand Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
| | - Yunwei Mao
- Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
| | - Tomás Palacios
- Department of Electrical Engineeringand Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
| | - Mildred S Dresselhaus
- Department of Physics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
| | - Sung Hyun Kim
- Department of Chemistry, Seoul National University, 599 Gwanak-ro, Gwanak-gu, Seoul, 151-742, Korea
| | - Jing Kong
- Department of Electrical Engineeringand Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
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31
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Chuang C, Matsunaga M, Liu FH, Woo TP, Aoki N, Lin LH, Wu BY, Ochiai Y, Liang CT. Probing weak localization in chemical vapor deposition graphene wide constriction using scanning gate microscopy. NANOTECHNOLOGY 2016; 27:075601. [PMID: 26762929 DOI: 10.1088/0957-4484/27/7/075601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Low-temperature scanning gate microscopy (LT-SGM) studies of graphene allow one to obtain important spatial information regarding coherent transport such as weak localization (WL) and universal conductance fluctuations. Although fascinating LT-SGM results on pristine graphene prepared by mechanical exfoliation have been reported in the literature, there appears to be a dearth of LT-SGM results on chemical vapor deposition (CVD)-grown graphene whose large scale and flexible substrate transferability make it an ideal candidate for coherent electronic applications. To this end, we have performed LT-SGM studies on CVD-grown graphene wide constriction (0.8 μm), which can be readily prepared by cost-effective optical lithography fully compatible with those in wafer foundry, in the WL regime. We find that the movable local gate can sensitively modulate the total conductance of the CVD graphene constriction possibly due to the intrinsic grain boundaries and merged domains, a great advantage for applications in coherent electronics. Moreover, such a conductance modulation by LT-SGM provides an additional, approximately magnetic-field-independent probe for studying coherent transport such as WL in graphene and spatial conductance variation.
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Affiliation(s)
- C Chuang
- Graduate School of Advanced Integration Science, Chiba University, Chiba 263-8522, Japan. Graduate Institute of Applied Physics, National Taiwan University, Taipei 106, Taiwan
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32
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Kochat V, Tiwary CS, Biswas T, Ramalingam G, Hsieh K, Chattopadhyay K, Raghavan S, Jain M, Ghosh A. Magnitude and Origin of Electrical Noise at Individual Grain Boundaries in Graphene. NANO LETTERS 2016; 16:562-567. [PMID: 26632989 DOI: 10.1021/acs.nanolett.5b04234] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Grain boundaries (GBs) are undesired in large area layered 2D materials as they degrade the device quality and their electronic performance. Here we show that the grain boundaries in graphene which induce additional scattering of carriers in the conduction channel also act as an additional and strong source of electrical noise especially at the room temperature. From graphene field effect transistors consisting of single GB, we find that the electrical noise across the graphene GBs can be nearly 10 000 times larger than the noise from equivalent dimensions in single crystalline graphene. At high carrier densities (n), the noise magnitude across the GBs decreases as ∝1/n, suggesting Hooge-type mobility fluctuations, whereas at low n close to the Dirac point, the noise magnitude could be quantitatively described by the fluctuations in the number of propagating modes across the GB.
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Affiliation(s)
- Vidya Kochat
- Department of Physics, ‡Department of Materials Engineering, §Materials Research Center, and ∥Centre for Nano Science and Engineering, Indian Institute of Science , Bangalore 560 012, India
| | - Chandra Sekhar Tiwary
- Department of Physics, ‡Department of Materials Engineering, §Materials Research Center, and ∥Centre for Nano Science and Engineering, Indian Institute of Science , Bangalore 560 012, India
| | - Tathagata Biswas
- Department of Physics, ‡Department of Materials Engineering, §Materials Research Center, and ∥Centre for Nano Science and Engineering, Indian Institute of Science , Bangalore 560 012, India
| | - Gopalakrishnan Ramalingam
- Department of Physics, ‡Department of Materials Engineering, §Materials Research Center, and ∥Centre for Nano Science and Engineering, Indian Institute of Science , Bangalore 560 012, India
| | - Kimberly Hsieh
- Department of Physics, ‡Department of Materials Engineering, §Materials Research Center, and ∥Centre for Nano Science and Engineering, Indian Institute of Science , Bangalore 560 012, India
| | - Kamanio Chattopadhyay
- Department of Physics, ‡Department of Materials Engineering, §Materials Research Center, and ∥Centre for Nano Science and Engineering, Indian Institute of Science , Bangalore 560 012, India
| | - Srinivasan Raghavan
- Department of Physics, ‡Department of Materials Engineering, §Materials Research Center, and ∥Centre for Nano Science and Engineering, Indian Institute of Science , Bangalore 560 012, India
| | - Manish Jain
- Department of Physics, ‡Department of Materials Engineering, §Materials Research Center, and ∥Centre for Nano Science and Engineering, Indian Institute of Science , Bangalore 560 012, India
| | - Arindam Ghosh
- Department of Physics, ‡Department of Materials Engineering, §Materials Research Center, and ∥Centre for Nano Science and Engineering, Indian Institute of Science , Bangalore 560 012, India
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33
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Shekhawat A, Ophus C, Ritchie RO. A generalized Read–Shockley model and large scale simulations for the energy and structure of graphene grain boundaries. RSC Adv 2016. [DOI: 10.1039/c6ra07584c] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The grain boundary (GB) energy is a quantity of fundamental importance for understanding several key properties of graphene.
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Affiliation(s)
- Ashivni Shekhawat
- Department of Materials Science and Engineering
- University of California Berkeley
- USA
- Miller Institute for Basic Research in Science
- University of California Berkeley
| | - Colin Ophus
- National Center for Electron Microscopy
- Molecular Foundry
- Lawrence Berkeley National Laboratory
- Berkeley
- USA
| | - Robert O. Ritchie
- Department of Materials Science and Engineering
- University of California Berkeley
- USA
- Materials Sciences Division
- Lawrence Berkeley National Laboratory
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34
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Kiraly B, Jacobberger RM, Mannix AJ, Campbell GP, Bedzyk MJ, Arnold MS, Hersam MC, Guisinger NP. Electronic and Mechanical Properties of Graphene-Germanium Interfaces Grown by Chemical Vapor Deposition. NANO LETTERS 2015; 15:7414-7420. [PMID: 26506006 DOI: 10.1021/acs.nanolett.5b02833] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Epitaxially oriented wafer-scale graphene grown directly on semiconducting Ge substrates is of high interest for both fundamental science and electronic device applications. To date, however, this material system remains relatively unexplored structurally and electronically, particularly at the atomic scale. To further understand the nature of the interface between graphene and Ge, we utilize ultrahigh vacuum scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) along with Raman and X-ray photoelectron spectroscopy to probe interfacial atomic structure and chemistry. STS reveals significant differences in electronic interactions between graphene and Ge(110)/Ge(111), which is consistent with a model of stronger interaction on Ge(110) leading to epitaxial growth. Raman spectra indicate that the graphene is considerably strained after growth, with more point-to-point variation on Ge(111). Furthermore, this native strain influences the atomic structure of the interface by inducing metastable and previously unobserved Ge surface reconstructions following annealing. These nonequilibrium reconstructions cover >90% of the surface and, in turn, modify both the electronic and mechanical properties of the graphene overlayer. Finally, graphene on Ge(001) represents the extreme strain case, where graphene drives the reorganization of the Ge surface into [107] facets. From this work, it is clear that the interaction between graphene and the underlying Ge is not only dependent on the substrate crystallographic orientation, but is also tunable and strongly related to the atomic reconfiguration of the graphene-Ge interface.
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Affiliation(s)
- Brian Kiraly
- Department of Materials Science and Engineering, Northwestern University , Evanston, Illinois 60208, United States
- Center for Nanoscale Materials, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Robert M Jacobberger
- Department of Materials Science and Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Andrew J Mannix
- Department of Materials Science and Engineering, Northwestern University , Evanston, Illinois 60208, United States
- Center for Nanoscale Materials, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Gavin P Campbell
- Department of Materials Science and Engineering, Northwestern University , Evanston, Illinois 60208, United States
| | - Michael J Bedzyk
- Department of Materials Science and Engineering, Northwestern University , Evanston, Illinois 60208, United States
- Department of Physics and Astronomy, Northwestern University , Evanston, Illinois 60208, United States
| | - Michael S Arnold
- Department of Materials Science and Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Mark C Hersam
- Department of Materials Science and Engineering, Northwestern University , Evanston, Illinois 60208, United States
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Nathan P Guisinger
- Center for Nanoscale Materials, Argonne National Laboratory , Argonne, Illinois 60439, United States
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35
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Nguyen VL, Lee YH. Towards Wafer-Scale Monocrystalline Graphene Growth and Characterization. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2015; 11:3512-28. [PMID: 25903119 DOI: 10.1002/smll.201500147] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2015] [Revised: 03/02/2015] [Indexed: 05/08/2023]
Abstract
Since its discovery in 2004, graphene has boosted numerous fundamental sciences and technological applications due to its massless Dirac particle-like linear band dispersion, that causes unprecedented physical properties. Among the various methods for synthesizing graphene, chemical vapor deposition is the most suitable approach for scalable production on a wafer scale, which is a critical step for practical applications. Graphene grain boundaries (GGBs), consisting of nonhexagonal carbon rings and therefore modulating the properties of graphene films, are inevitably formed via the merging of adjacent graphene domains with different orientations. Large-area monocrystalline graphene synthesis without forming GGBs has been challenging, let alone observing such boundaries. Here, an up-to-date review is presented of how to grow wafer-scale monocrystalline graphene without GGBs. One approach is to make single domain sizes as large as possible by reducing or passivating the number of nucleation sites. Another approach is to align graphene domains in identical orientations, and then merge them atomically. The recently developed methods for observing graphene orientation and GGBs both at the atomic and macro-scales are also presented. Finally, perspectives for future research in graphene growth are discussed.
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Affiliation(s)
- Van Luan Nguyen
- IBS Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Sungkyunkwan University, Suwon, 440-746, Republic of Korea
- Department of Energy Science, Sungkyunkwan University, Suwon, 440-746, Republic of Korea
| | - Young Hee Lee
- IBS Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Sungkyunkwan University, Suwon, 440-746, Republic of Korea
- Department of Energy Science, Sungkyunkwan University, Suwon, 440-746, Republic of Korea
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36
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Yasaei P, Fathizadeh A, Hantehzadeh R, Majee AK, El-Ghandour A, Estrada D, Foster C, Aksamija Z, Khalili-Araghi F, Salehi-Khojin A. Bimodal Phonon Scattering in Graphene Grain Boundaries. NANO LETTERS 2015; 15:4532-4540. [PMID: 26035002 DOI: 10.1021/acs.nanolett.5b01100] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Graphene has served as the model 2D system for over a decade, and the effects of grain boundaries (GBs) on its electrical and mechanical properties are very well investigated. However, no direct measurement of the correlation between thermal transport and graphene GBs has been reported. Here, we report a simultaneous comparison of thermal transport in supported single crystalline graphene to thermal transport across an individual graphene GB. Our experiments show that thermal conductance (per unit area) through an isolated GB can be up to an order of magnitude lower than the theoretically anticipated values. Our measurements are supported by Boltzmann transport modeling which uncovers a new bimodal phonon scattering phenomenon initiated by the GB structure. In this novel scattering mechanism, boundary roughness scattering dominates the phonon transport in low-mismatch GBs, while for higher mismatch angles there is an additional resistance caused by the formation of a disordered region at the GB. Nonequilibrium molecular dynamics simulations verify that the amount of disorder in the GB region is the determining factor in impeding thermal transport across GBs.
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Affiliation(s)
| | | | | | - Arnab K Majee
- §Electrical and Computer Engineering Department, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
| | - Ahmed El-Ghandour
- ∥Department of Civil and Material Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - David Estrada
- ⊥Department of Materials Science and Engineering, Boise State University, Boise, Idaho 83725, United States
| | - Craig Foster
- ∥Department of Civil and Material Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Zlatan Aksamija
- §Electrical and Computer Engineering Department, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
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37
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Nguyen VL, Shin BG, Duong DL, Kim ST, Perello D, Lim YJ, Yuan QH, Ding F, Jeong HY, Shin HS, Lee SM, Chae SH, Vu QA, Lee SH, Lee YH. Seamless stitching of graphene domains on polished copper (111) foil. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2015; 27:1376-82. [PMID: 25523458 DOI: 10.1002/adma.201404541] [Citation(s) in RCA: 152] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 11/13/2014] [Indexed: 05/23/2023]
Abstract
Seamless stitching of graphene domains on polished copper (111) is proved clearly not only at atomic scale by scanning tunnelling microscopy (STM) and transmission electron micoscopy (TEM), but also at the macroscale by optical microscopy after UV-treatment. Using this concept of seamless stitching, synthesis of 6 cm × 3 cm monocrystalline graphene without grain boundaries on polished copper (111) foil is possible, which is only limited by the chamber size.
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Affiliation(s)
- Van Luan Nguyen
- IBS Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Sungkyunkwan University, Suwon, 440-746, Republic of Korea; Department of Energy Science, Department of Physics, Sungkyunkwan University, Suwon, 440-746, Republic of Korea
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38
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Ma C, Sun H, Du H, Wang J, Zhao A, Li Q, Wang B, Hou JG. Structural and electronic properties of an ordered grain boundary formed by separated (1,0) dislocations in graphene. NANOSCALE 2015; 7:3055-3059. [PMID: 25603956 DOI: 10.1039/c4nr06789d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We present an investigation of the structural and electronic properties of an ordered grain boundary (GB) formed by separated pentagon-heptagon pairs in single-layer graphene/SiO2 using scanning tunneling microscopy/spectroscopy (STM/STS), coupled with density functional theory (DFT) calculations. It is observed that the pentagon-heptagon pairs, i.e., (1,0) dislocations, form a periodic quasi-one-dimensional chain. The (1,0) dislocations are separated by 8 transverse rows of carbon rings, with a period of ∼2.1 nm. The protruded feature of each dislocation shown in the STM images reflects its out-of-plane buckling structure, which is supported by the DFT simulations. The STS spectra recorded along the small-angle GB show obvious differential-conductance peaks, the positions of which qualitatively accord with the van Hove singularities from the DFT calculations.
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Affiliation(s)
- Chuanxu Ma
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.
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39
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Wood JD, Doidge GP, Carrion EA, Koepke JC, Kaitz JA, Datye I, Behnam A, Hewaparakrama J, Aruin B, Chen Y, Dong H, Haasch RT, Lyding JW, Pop E. Annealing free, clean graphene transfer using alternative polymer scaffolds. NANOTECHNOLOGY 2015; 26:055302. [PMID: 25580991 DOI: 10.1088/0957-4484/26/5/055302] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
We examine the transfer of graphene grown by chemical vapor deposition (CVD) with polymer scaffolds of poly(methyl methacrylate) (PMMA), poly(lactic acid) (PLA), poly(phthalaldehyde) (PPA), and poly(bisphenol A carbonate) (PC). We find that optimally reactive PC scaffolds provide the cleanest graphene transfers without any annealing, after extensive comparison with optical microscopy, x-ray photoelectron spectroscopy, atomic force microscopy, and scanning tunneling microscopy. Comparatively, films transferred with PLA, PPA, PMMA/PC, and PMMA have a two-fold higher roughness and a five-fold higher chemical doping. Using PC scaffolds, we demonstrate the clean transfer of CVD multilayer graphene, fluorinated graphene, and hexagonal boron nitride. Our annealing free, PC transfers enable the use of atomically-clean nanomaterials in biomolecule encapsulation and flexible electronic applications.
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Affiliation(s)
- Joshua D Wood
- Dept. of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. Micro and Nanotechnology Lab, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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40
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Sun M, Liu H, Liu Y, Qu J, Li J. Graphene-based transition metal oxide nanocomposites for the oxygen reduction reaction. NANOSCALE 2015; 7:1250-69. [PMID: 25502117 DOI: 10.1039/c4nr05838k] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The development of low cost, durable and efficient nanocatalysts to substitute expensive and rare noble metals (e.g. Pt, Au and Pd) in overcoming the sluggish kinetic process of the oxygen reduction reaction (ORR) is essential to satisfy the demand for sustainable energy conversion and storage in the future. Graphene based transition metal oxide nanocomposites have extensively been proven to be a type of promising highly efficient and economic nanocatalyst for optimizing the ORR to solve the world-wide energy crisis. Synthesized nanocomposites exhibit synergetic advantages and avoid the respective disadvantages. In this feature article, we concentrate on the recent leading works of different categories of introduced transition metal oxides on graphene: from the commonly-used classes (FeOx, MnOx, and CoOx) to some rare and heat-studied issues (TiOx, NiCoOx and Co-MnOx). Moreover, the morphologies of the supported oxides on graphene with various dimensional nanostructures, such as one dimensional nanocrystals, two dimensional nanosheets/nanoplates and some special multidimensional frameworks are further reviewed. The strategies used to synthesize and characterize these well-designed nanocomposites and their superior properties for the ORR compared to the traditional catalysts are carefully summarized. This work aims to highlight the meaning of the multiphase establishment of graphene-based transition metal oxide nanocomposites and its structural-dependent ORR performance and mechanisms.
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Affiliation(s)
- Meng Sun
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China.
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41
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Yazyev OV, Chen YP. Polycrystalline graphene and other two-dimensional materials. NATURE NANOTECHNOLOGY 2014; 9:755-67. [PMID: 25152238 DOI: 10.1038/nnano.2014.166] [Citation(s) in RCA: 204] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Accepted: 07/15/2014] [Indexed: 05/02/2023]
Abstract
Graphene, a single atomic layer of graphitic carbon, has attracted intense attention because of its extraordinary properties that make it a suitable material for a wide range of technological applications. Large-area graphene films, which are necessary for industrial applications, are typically polycrystalline - that is, composed of single-crystalline grains of varying orientation joined by grain boundaries. Here, we present a review of the large body of research reported in the past few years on polycrystalline graphene. We discuss its growth and formation, the microscopic structure of grain boundaries and their relations to other types of topological defect such as dislocations. The Review further covers electronic transport, optical and mechanical properties pertaining to the characterizations of grain boundaries, and applications of polycrystalline graphene. We also discuss research, still in its infancy, performed on other two-dimensional materials such as transition metal dichalcogenides, and offer perspectives for future directions of research.
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Affiliation(s)
- Oleg V Yazyev
- Institute of Theoretical Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Yong P Chen
- Department of Physics and School of Electrical and Computer Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA
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42
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Chemical sensing with switchable transport channels in graphene grain boundaries. Nat Commun 2014; 5:4911. [PMID: 25241799 DOI: 10.1038/ncomms5911] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Accepted: 08/05/2014] [Indexed: 11/09/2022] Open
Abstract
Grain boundaries can markedly affect the electronic, thermal, mechanical and optical properties of a polycrystalline graphene. While in many applications the presence of grain boundaries in graphene is undesired, here we show that they have an ideal structure for the detection of chemical analytes. We observe that an isolated graphene grain boundary has ~300 times higher sensitivity to the adsorbed gas molecules than a single-crystalline graphene grain. Our electronic structure and transport modelling reveal that the ultra-sensitivity in grain boundaries is caused by a synergetic combination of gas molecules accumulation at the grain boundary, together with the existence of a sharp onset energy in the transmission spectrum of its conduction channels. The discovered sensing platform opens up new pathways for the design of nanometre-scale highly sensitive chemical detectors.
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Yu SU, Park B, Cho Y, Hyun S, Kim JK, Kim KS. Simultaneous visualization of graphene grain boundaries and wrinkles with structural information by gold deposition. ACS NANO 2014; 8:8662-8668. [PMID: 25117455 DOI: 10.1021/nn503550d] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Although line defects such as grain boundaries (GBs) and wrinkles are unavoidable in graphene, difficulties in identification preclude studying their impact on electronic and mechanical properties. As previous methods focus on a single type of line defect, simultaneous measurements of both GBs and wrinkles with detailed structural information have not been reported. Here, we introduce effective visualization of both line defects by controlled gold deposition. Upon depositing gold on graphene, single lines and double lines of gold nanoparticles (NPs) are formed along GBs and wrinkles, respectively. Moreover, it is possible to analyze whether a GB is stitched or overlapped, whether a wrinkle is standing or folded, and the width of the standing collapsed wrinkle. Theoretical calculations show that the characteristic morphology of gold NPs is due to distinct binding energies of line defects, which are correlated to disrupting diffusion of NPs. Our approach could be further exploited to investigate the defect structures of other two-dimensional materials.
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Cummings AW, Duong DL, Nguyen VL, Van Tuan D, Kotakoski J, Barrios Vargas JE, Lee YH, Roche S. Charge transport in polycrystalline graphene: challenges and opportunities. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:5079-94. [PMID: 24903153 DOI: 10.1002/adma.201401389] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 04/30/2014] [Indexed: 05/27/2023]
Abstract
Graphene has attracted significant interest both for exploring fundamental science and for a wide range of technological applications. Chemical vapor deposition (CVD) is currently the only working approach to grow graphene at wafer scale, which is required for industrial applications. Unfortunately, CVD graphene is intrinsically polycrystalline, with pristine graphene grains stitched together by disordered grain boundaries, which can be either a blessing or a curse. On the one hand, grain boundaries are expected to degrade the electrical and mechanical properties of polycrystalline graphene, rendering the material undesirable for many applications. On the other hand, they exhibit an increased chemical reactivity, suggesting their potential application to sensing or as templates for synthesis of one-dimensional materials. Therefore, it is important to gain a deeper understanding of the structure and properties of graphene grain boundaries. Here, we review experimental progress on identification and electrical and chemical characterization of graphene grain boundaries. We use numerical simulations and transport measurements to demonstrate that electrical properties and chemical modification of graphene grain boundaries are strongly correlated. This not only provides guidelines for the improvement of graphene devices, but also opens a new research area of engineering graphene grain boundaries for highly sensitive electro-biochemical devices.
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Affiliation(s)
- Aron W Cummings
- ICN2 - Institut Català de Nanociència i Nanotecnologia, Campus UAB, 08193, Bellaterra, Barcelona, Spain
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Yang B, Xu H, Lu J, Loh KP. Periodic Grain Boundaries Formed by Thermal Reconstruction of Polycrystalline Graphene Film. J Am Chem Soc 2014; 136:12041-6. [DOI: 10.1021/ja5054847] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Bao Yang
- Department
of Chemistry and Graphene Research
Centre, National University of Singapore, 3 Science Drive 3, Singapore 117543
| | - Hai Xu
- Department
of Chemistry and Graphene Research
Centre, National University of Singapore, 3 Science Drive 3, Singapore 117543
| | - Jiong Lu
- Department
of Chemistry and Graphene Research
Centre, National University of Singapore, 3 Science Drive 3, Singapore 117543
| | - Kian Ping Loh
- Department
of Chemistry and Graphene Research
Centre, National University of Singapore, 3 Science Drive 3, Singapore 117543
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46
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Ogawa Y, Komatsu K, Kawahara K, Tsuji M, Tsukagoshi K, Ago H. Structure and transport properties of the interface between CVD-grown graphene domains. NANOSCALE 2014; 6:7288-7294. [PMID: 24847777 DOI: 10.1039/c3nr06828e] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
During the chemical vapor deposition (CVD) growth of graphene, graphene domains grown on a Cu surface merge together and form a uniform graphene sheet. For high-performance electronics and other applications, it is important to understand the interfacial structure of the merged domains, as well as their influence on the physical properties of graphene. We synthesized large hexagonal graphene domains with controlled orientations on a heteroepitaxial Cu film and studied the structure and properties of the interfaces between the domains mainly merged with the same angle. Although the merged domains have various interfaces with/without wrinkles and/or increased defect-related Raman D-band intensity, the intra-domain transport showed higher carrier mobility reaching 20,000 cm(2) V(-1) s(-1) on SiO2 at 280 K (the mean value was 7200 cm(2) V(-1) s(-1)) than that measured for inter-domain areas, 6400 cm(2) V(-1) s(-1) (mean value 2000 cm(2) V(-1) s(-1)). The temperature dependence of the mobility suggests that impurity scattering dominates at the interface even for the merged domains with the same orientation. This study highlights the importance of domain interfaces, especially on the carrier transport properties, in CVD-grown graphene.
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Affiliation(s)
- Yui Ogawa
- Graduate School of Engineering Sciences, Kyushu University, Kasuga, Fukuoka 816-8580, Japan
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Petrović M, Šrut Rakić I, Runte S, Busse C, Sadowski JT, Lazić P, Pletikosić I, Pan ZH, Milun M, Pervan P, Atodiresei N, Brako R, Šokčević D, Valla T, Michely T, Kralj M. The mechanism of caesium intercalation of graphene. Nat Commun 2014; 4:2772. [PMID: 24212475 DOI: 10.1038/ncomms3772] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 10/15/2013] [Indexed: 12/23/2022] Open
Abstract
Properties of many layered materials, including copper- and iron-based superconductors, topological insulators, graphite and epitaxial graphene, can be manipulated by the inclusion of different atomic and molecular species between the layers via a process known as intercalation. For example, intercalation in graphite can lead to superconductivity and is crucial in the working cycle of modern batteries and supercapacitors. Intercalation involves complex diffusion processes along and across the layers; however, the microscopic mechanisms and dynamics of these processes are not well understood. Here we report on a novel mechanism for intercalation and entrapment of alkali atoms under epitaxial graphene. We find that the intercalation is adjusted by the van der Waals interaction, with the dynamics governed by defects anchored to graphene wrinkles. Our findings are relevant for the future design and application of graphene-based nano-structures. Similar mechanisms can also have a role for intercalation of layered materials.
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Affiliation(s)
- M Petrović
- Institut za fiziku, Bijenička 46, 10000 Zagreb, Croatia
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Xu Y, Li Z, Duan W. Thermal and thermoelectric properties of graphene. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2014; 10:2182-99. [PMID: 24610791 DOI: 10.1002/smll.201303701] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2013] [Revised: 01/14/2014] [Indexed: 05/12/2023]
Abstract
The subject of thermal transport at the mesoscopic scale and in low-dimensional systems is interesting for both fundamental research and practical applications. As the first example of truly two-dimensional materials, graphene has exceptionally high thermal conductivity, and thus provides an ideal platform for the research. Here we review recent studies on thermal and thermoelectric properties of graphene, with an emphasis on experimental progresses. A general physical picture based on the Landauer transport formalism is introduced to understand underlying mechanisms. We show that the superior thermal conductivity of graphene is contributed not only by large ballistic thermal conductance but also by very long phonon mean free path (MFP). The long phonon MFP, explained by the low-dimensional nature and high sample purity of graphene, results in important isotope effects and size effects on thermal conduction. In terms of various scattering mechanisms in graphene, several approaches are suggested to control thermal conductivity. Among them, introducing rough boundaries and weakly-coupled interfaces are promising ways to suppress thermal conduction effectively. We also discuss the Seebeck effect of graphene. Graphene itself might not be a good thermoelectric material. However, the concepts developed by graphene research might be applied to improve thermoelectric performance of other materials.
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Affiliation(s)
- Yong Xu
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing, 100084, People's Republic of China; Institue for Advanced Study, Tsinghua University, Beijing, 100084, People's Republic of China; Department of Physics, McCullough Building, Stanford University, Stanford, CA, 94305-4045, USA
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49
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Ma C, Sun H, Zhao Y, Li B, Li Q, Zhao A, Wang X, Luo Y, Yang J, Wang B, Hou JG. Evidence of van Hove singularities in ordered grain boundaries of graphene. PHYSICAL REVIEW LETTERS 2014; 112:226802. [PMID: 24949783 DOI: 10.1103/physrevlett.112.226802] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Indexed: 06/03/2023]
Abstract
It has long been under debate whether the electron transport performance of graphene could be enhanced by the possible occurrence of van Hove singularities in grain boundaries. Here, we provide direct experimental evidence to confirm the existence of van Hove singularity states close to the Fermi energy in certain ordered grain boundaries using scanning tunneling microscopy. The intrinsic atomic and electronic structures of two ordered grain boundaries, one with alternative pentagon and heptagon rings and the other with alternative pentagon pair and octagon rings, are determined. It is firmly verified that the carrier concentration and, thus, the conductance around ordered grain boundaries can be significantly enhanced by the van Hove singularity states. This finding strongly suggests that a graphene nanoribbon with a properly embedded ordered grain boundary can be a promising structure to improve the performance of graphene-based electronic devices.
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Affiliation(s)
- Chuanxu Ma
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Haifeng Sun
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Yeliang Zhao
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Bin Li
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Qunxiang Li
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Aidi Zhao
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Xiaoping Wang
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Yi Luo
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Jinlong Yang
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Bing Wang
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - J G Hou
- Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
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50
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Procházka P, Mach J, Bischoff D, Lišková Z, Dvořák P, Vaňatka M, Simonet P, Varlet A, Hemzal D, Petrenec M, Kalina L, Bartošík M, Ensslin K, Varga P, Čechal J, Šikola T. Ultrasmooth metallic foils for growth of high quality graphene by chemical vapor deposition. NANOTECHNOLOGY 2014; 25:185601. [PMID: 24739598 DOI: 10.1088/0957-4484/25/18/185601] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Synthesis of graphene by chemical vapor deposition is a promising route for manufacturing large-scale high-quality graphene for electronic applications. The quality of the employed substrates plays a crucial role, since the surface roughness and defects alter the graphene growth and cause difficulties in the subsequent graphene transfer. Here, we report on ultrasmooth high-purity copper foils prepared by sputter deposition of Cu thin film on a SiO2/Si template, and the subsequent peeling off of the metallic layer from the template. The surface displays a low level of oxidation and contamination, and the roughness of the foil surface is generally defined by the template, and was below 0.6 nm even on a large scale. The roughness and grain size increase occurred during both the annealing of the foils, and catalytic growth of graphene from methane (≈1000 °C), but on the large scale still remained far below the roughness typical for commercial foils. The micro-Raman spectroscopy and transport measurements proved the high quality of graphene grown on such foils, and the room temperature mobility of the graphene grown on the template stripped foil was three times higher compared to that of one grown on the commercial copper foil. The presented high-quality copper foils are expected to provide large-area substrates for the production of graphene suitable for electronic applications.
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Affiliation(s)
- Pavel Procházka
- CEITEC-Central European Institute of Technology, Brno University of Technology, Technická 3058/10, 616 00 Brno, Czech Republic. Institute of Physical Engineering, Brno University of Technology, Technická 2896/2, 616 69 Brno, Czech Republic
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