TY - JOUR
T1 - Structure of quasi-free-standing graphene on the SiC (0001) surface prepared by the rapid cooling method
AU - Sumi, Tatsuya
AU - Nagai, Kazuki
AU - Bao, Jianfeng
AU - Terasawa, Tomo O.
AU - Norimatsu, Wataru
AU - Kusunoki, Michiko
AU - Wakabayashi, Yusuke
N1 - Funding Information:
The authors thank Mr. S. Miyagawa for assistance with diffraction data analysis. This work was supported by a Grant-in-Aid for Scientific Research [Japan Society for the Promotion of Science (JSPS) KAKENHI, Grant Nos. JP26105008 and JP18H01889] and the MEXT Elements Strategy Initiative to Form Core Research Center (Grant No. JPMXP0112101001). The synchrotron radiation experiments at the Photon Factory were performed with the approval of the Photon Factory Program Advisory Committee (Proposal No. 2015S2-009). We thank Tim Cooper, Ph.D., from Edanz Group (https://en-author-services.edanzgroup.com/ac) for editing a draft of this manuscript.
Publisher Copyright:
© 2020 Author(s).
PY - 2020/10/5
Y1 - 2020/10/5
N2 - A systematic structural study of epitaxial graphene samples on the SiC (0001) surface has been performed by the surface x-ray diffraction method, which is a non-contact technique. For samples with only a buffer layer, one layer graphene, and multilayer graphene, the distances between the buffer layer and the surface Si atoms were found to be 2.3 Å. This value is the same as reported values. For quasi-free-standing graphene samples prepared by the rapid cooling method [Bao et al., Phys. Rev. Lett. 117, 205501 (2016)], there was no buffer layer and the distance between the quasi-free-standing graphene and the surface Si atoms was 3.5 Å, which is significantly shorter than the value in hydrogen-intercalated graphene and slightly longer than the interplane distance in graphite. The Si occupancy deviated from unity within 1 nm of the SiC surface. The depth profile of the Si occupancy showed little sample dependence, and it was reproduced by a simple atomistic model based on random hopping of Si atoms.
AB - A systematic structural study of epitaxial graphene samples on the SiC (0001) surface has been performed by the surface x-ray diffraction method, which is a non-contact technique. For samples with only a buffer layer, one layer graphene, and multilayer graphene, the distances between the buffer layer and the surface Si atoms were found to be 2.3 Å. This value is the same as reported values. For quasi-free-standing graphene samples prepared by the rapid cooling method [Bao et al., Phys. Rev. Lett. 117, 205501 (2016)], there was no buffer layer and the distance between the quasi-free-standing graphene and the surface Si atoms was 3.5 Å, which is significantly shorter than the value in hydrogen-intercalated graphene and slightly longer than the interplane distance in graphite. The Si occupancy deviated from unity within 1 nm of the SiC surface. The depth profile of the Si occupancy showed little sample dependence, and it was reproduced by a simple atomistic model based on random hopping of Si atoms.
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U2 - 10.1063/5.0021071
DO - 10.1063/5.0021071
M3 - Article
AN - SCOPUS:85092444502
SN - 0003-6951
VL - 117
JO - Applied Physics Letters
JF - Applied Physics Letters
IS - 14
M1 - 143102-1
ER -