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Huang W, Seo JA, Canavan MP, Gambardella P, Stepanow S. Observation of different Li intercalation states and local doping in epitaxial mono- and bilayer graphene on SiC(0001). NANOSCALE 2024; 16:3160-3165. [PMID: 38259148 PMCID: PMC10851339 DOI: 10.1039/d3nr03070a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 01/10/2024] [Indexed: 01/24/2024]
Abstract
Li intercalation is commonly used to enhance the carrier density in epitaxial graphene and mitigate coupling to the substrate. So far, the understanding of the intercalation process, particularly how Li penetrates different layers above the substrate, and its impact on electron transport remains incomplete. Here, we report different phases of Li intercalation and their kinetic processes in epitaxial mono- and bilayer graphene grown on SiC. The distinct doping effects of each intercalation phase are characterized using scanning tunneling spectroscopy. Furthermore, changes in the local conduction regimes are directly mapped by scanning tunneling potentiometry and attributed to different charge transfer states of the intercalated Li. The stable intercalation marked by the formation of Li-Si bonds leads to a significant 56% reduction in sheet resistance of the resulting quasi-free bilayer graphene, as compared to the pristine monolayer graphene.
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Affiliation(s)
- Wei Huang
- Department of Materials, ETH Zurich, 8093 Zurich, Switzerland.
| | - Jeong Ah Seo
- Department of Materials, ETH Zurich, 8093 Zurich, Switzerland.
| | - Mark P Canavan
- Department of Materials, ETH Zurich, 8093 Zurich, Switzerland.
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Paillet C, Vézian S, Matei C, Michon A, Damilano B, Dussaigne A, Hyot B. InGaN islands and thin films grown on epitaxial graphene. NANOTECHNOLOGY 2020; 31:405601. [PMID: 32485697 DOI: 10.1088/1361-6528/ab98bd] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In this work, the growth of InGaN on epitaxial graphene by molecular beam epitaxy is studied. The nucleation of the alloy follows a three-dimensional (3D) growth mode in the observed temperature range of 515 °C-765 °C, leading to the formation of dendrite-like islands. Careful Raman scattering experiments show that the graphene underneath is not degraded by the InGaN growth. Moreover, lateral displacement of the nuclei during an atomic force microscopy (AFM) scan demonstrates weak bonding interactions between the InGaN and the graphene. Finally, a longer growth time of the alloy gives rise to a compact thin film in a partial epitaxial relationship with the SiC underneath the graphene.
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Affiliation(s)
- C Paillet
- Université Grenoble Alpes, CEA-LETI, 17 Avenue des Martyrs, F-38054 Grenoble, France. Université Côte d'Azur, CNRS-CRHEA, rue Bernard Gregory, 06560 Valbonne, France
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Hu T, Hui X, Zhang X, Liu X, Ma D, Wei R, Xu K, Ma F. Nanostructured Bi Grown on Epitaxial Graphene/SiC. J Phys Chem Lett 2018; 9:5679-5684. [PMID: 30212218 DOI: 10.1021/acs.jpclett.8b02246] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Controllable growth of metal nanostructures on epitaxial graphene (EG) is particularly interesting and important for the applications in electric devices. Bi nanostructures on EG/SiC are fabricated through thermal decomposition of SiC and subsequent low-flux evaporation of Bi. The orientation, atomic structure, and thickness-dependent electronic states of Bi are investigated by scanning tunneling microscopy/spectroscopy. It is found that metallic Bi nanoflakes and nanorods prefer to grow on the SiC buffer layer region with higher diffusion barrier, but Bi nanoribbons are formed on regularly ordered EG. Although the thicker Bi nanoribbons of 11 monolayers on EG are still metallic, the thinner ones become semiconducting owing to the interfacial effect. This indicates that the electronic states and physical properties of Bi are substrate-dependent. The results are helpful for the design of Bi- and graphene-based electronic and spintronic devices.
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Affiliation(s)
- Tingwei Hu
- State Key Laboratory for Mechanical Behavior of Materials , Xi'an Jiaotong University , Xi'an 710049 , Shaanxi , China
- Collaborative Innovation Center of Suzhou Nano Science and Technology , Xi'an Jiaotong University , Suzhou 215123 , Jiangsu , China
| | - Xin Hui
- State Key Laboratory for Mechanical Behavior of Materials , Xi'an Jiaotong University , Xi'an 710049 , Shaanxi , China
| | - Xiaohe Zhang
- State Key Laboratory for Mechanical Behavior of Materials , Xi'an Jiaotong University , Xi'an 710049 , Shaanxi , China
| | - Xiangtai Liu
- State Key Laboratory for Mechanical Behavior of Materials , Xi'an Jiaotong University , Xi'an 710049 , Shaanxi , China
| | - Dayan Ma
- State Key Laboratory for Mechanical Behavior of Materials , Xi'an Jiaotong University , Xi'an 710049 , Shaanxi , China
| | - Ran Wei
- School of Materials Science and Engineering , Zhengzhou University , Zhengzhou 450001 , China
| | - Kewei Xu
- State Key Laboratory for Mechanical Behavior of Materials , Xi'an Jiaotong University , Xi'an 710049 , Shaanxi , China
- Department of Physics and Opt-electronic Engineering , Xi'an University of Arts and Science , Xi'an 710065 , Shaanxi , China
| | - Fei Ma
- State Key Laboratory for Mechanical Behavior of Materials , Xi'an Jiaotong University , Xi'an 710049 , Shaanxi , China
- Collaborative Innovation Center of Suzhou Nano Science and Technology , Xi'an Jiaotong University , Suzhou 215123 , Jiangsu , China
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Pelloni S, Lazzeretti P. Polygonal current models for polycyclic aromatic hydrocarbons and graphene sheets of various shapes. J Comput Chem 2017; 39:21-34. [DOI: 10.1002/jcc.25076] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 09/15/2017] [Accepted: 09/18/2017] [Indexed: 01/11/2023]
Affiliation(s)
- Stefano Pelloni
- ITIS Galileo Galilei, Via Martiri di Cefalonia 14; S. Secondo, Parma 43017 Italy
| | - Paolo Lazzeretti
- Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Via del Fosso del Cavaliere 100; Roma 00133 Italy
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