Structure and electronic properties of closed-ring defects in epitaxial graphene
A number of past studies have focused on point and line defects in graphene epitaxially grown on SiC substrates. However, few studies have investigated closed-ring defects formed within grain boundary loops. The present study addresses this issue by applying low-temperature scanning tunneling micros...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2020-01-01
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| Series: | Materials Research Express |
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| Online Access: | https://doi.org/10.1088/2053-1591/ab8ee6 |
| _version_ | 1797746383191539712 |
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| author | Yan Chen Meng-Chen Li Qi-Ming Wang Guo-Sheng Wang Xin Wei Guo-Feng Song Xiang-Mu Kong Yun Xu Ying Liu |
| author_facet | Yan Chen Meng-Chen Li Qi-Ming Wang Guo-Sheng Wang Xin Wei Guo-Feng Song Xiang-Mu Kong Yun Xu Ying Liu |
| author_sort | Yan Chen |
| collection | DOAJ |
| description | A number of past studies have focused on point and line defects in graphene epitaxially grown on SiC substrates. However, few studies have investigated closed-ring defects formed within grain boundary loops. The present study addresses this issue by applying low-temperature scanning tunneling microscopy/spectroscopy to investigate the atomic structures of closed-ring defects in graphene epitaxially grown on 4H-SiC, and to evaluate their effects on the electron state density. The results indicate that the orientations of the graphene lattice inside and outside of grain boundary loop structures are rotated uniformly by an angle of 30° relative to each other, suggesting that closed-ring defects are highly ordered and are mainly composed of clusters of pentagon-heptagon carbon rings and highly ordered pentagon-heptagon chains. In addition, the spectroscopy results reveal for the first time that the density of electron states inside a closed-ring defect is strongly localized and position-dependent. Moreover, these closed-ring defects can eliminate intervalley scattering while maintaining intravalley scattering. These findings are not only helpful for contributing to a deeper understanding of the effects of closed-ring defects in graphene, but also present a potentially useful valley-filtering mechanism for charge carries that can be applied to the practical development of all-electric valley-based devices. |
| first_indexed | 2024-03-12T15:36:03Z |
| format | Article |
| id | doaj.art-2436d0f78e5e4234a5d658eca5010355 |
| institution | Directory Open Access Journal |
| issn | 2053-1591 |
| language | English |
| last_indexed | 2024-03-12T15:36:03Z |
| publishDate | 2020-01-01 |
| publisher | IOP Publishing |
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| series | Materials Research Express |
| spelling | doaj.art-2436d0f78e5e4234a5d658eca50103552023-08-09T16:12:15ZengIOP PublishingMaterials Research Express2053-15912020-01-017505560210.1088/2053-1591/ab8ee6Structure and electronic properties of closed-ring defects in epitaxial grapheneYan Chen0Meng-Chen Li1Qi-Ming Wang2Guo-Sheng Wang3Xin Wei4Guo-Feng Song5Xiang-Mu Kong6Yun Xu7https://orcid.org/0000-0002-6143-9282Ying Liu8Institute of Semiconductors, Chinese Academy of Sciences , Beijing, 100083, People’s Republic of China; College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences , Beijing, 100049, People’s Republic of China; Beijing Key Laboratory of Inorganic Stretchable and Flexible Information Technology, Beijing 100083, People’s Republic of ChinaCollege of Chemistry, Beijing Normal University , Beijing, 100875, People’s Republic of ChinaCollege of Chemistry, Beijing Normal University , Beijing, 100875, People’s Republic of China; College of Physics and Engineering, Qufu Normal University, Qufu 273165, People’s Republic of ChinaCollege of Chemistry, Beijing Normal University , Beijing, 100875, People’s Republic of ChinaInstitute of Semiconductors, Chinese Academy of Sciences , Beijing, 100083, People’s Republic of China; College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences , Beijing, 100049, People’s Republic of China; Beijing Key Laboratory of Inorganic Stretchable and Flexible Information Technology, Beijing 100083, People’s Republic of ChinaInstitute of Semiconductors, Chinese Academy of Sciences , Beijing, 100083, People’s Republic of China; College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences , Beijing, 100049, People’s Republic of China; Beijing Key Laboratory of Inorganic Stretchable and Flexible Information Technology, Beijing 100083, People’s Republic of ChinaCollege of Physics and Engineering, Qufu Normal University, Qufu 273165, People’s Republic of China; School of Physics and Optoelectronic Engineering, Ludong University, Yantai 264025, People’s Republic of ChinaInstitute of Semiconductors, Chinese Academy of Sciences , Beijing, 100083, People’s Republic of China; College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences , Beijing, 100049, People’s Republic of China; Beijing Key Laboratory of Inorganic Stretchable and Flexible Information Technology, Beijing 100083, People’s Republic of ChinaCollege of Chemistry, Beijing Normal University , Beijing, 100875, People’s Republic of ChinaA number of past studies have focused on point and line defects in graphene epitaxially grown on SiC substrates. However, few studies have investigated closed-ring defects formed within grain boundary loops. The present study addresses this issue by applying low-temperature scanning tunneling microscopy/spectroscopy to investigate the atomic structures of closed-ring defects in graphene epitaxially grown on 4H-SiC, and to evaluate their effects on the electron state density. The results indicate that the orientations of the graphene lattice inside and outside of grain boundary loop structures are rotated uniformly by an angle of 30° relative to each other, suggesting that closed-ring defects are highly ordered and are mainly composed of clusters of pentagon-heptagon carbon rings and highly ordered pentagon-heptagon chains. In addition, the spectroscopy results reveal for the first time that the density of electron states inside a closed-ring defect is strongly localized and position-dependent. Moreover, these closed-ring defects can eliminate intervalley scattering while maintaining intravalley scattering. These findings are not only helpful for contributing to a deeper understanding of the effects of closed-ring defects in graphene, but also present a potentially useful valley-filtering mechanism for charge carries that can be applied to the practical development of all-electric valley-based devices.https://doi.org/10.1088/2053-1591/ab8ee6graphenegrain boundaryelectronic propertiesscanning tunneling microscopy |
| spellingShingle | Yan Chen Meng-Chen Li Qi-Ming Wang Guo-Sheng Wang Xin Wei Guo-Feng Song Xiang-Mu Kong Yun Xu Ying Liu Structure and electronic properties of closed-ring defects in epitaxial graphene Materials Research Express graphene grain boundary electronic properties scanning tunneling microscopy |
| title | Structure and electronic properties of closed-ring defects in epitaxial graphene |
| title_full | Structure and electronic properties of closed-ring defects in epitaxial graphene |
| title_fullStr | Structure and electronic properties of closed-ring defects in epitaxial graphene |
| title_full_unstemmed | Structure and electronic properties of closed-ring defects in epitaxial graphene |
| title_short | Structure and electronic properties of closed-ring defects in epitaxial graphene |
| title_sort | structure and electronic properties of closed ring defects in epitaxial graphene |
| topic | graphene grain boundary electronic properties scanning tunneling microscopy |
| url | https://doi.org/10.1088/2053-1591/ab8ee6 |
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