Structure and dynamics investigations of a partially hydrogenated graphene/Ni(111) surface

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• 作者：Emanuel Bahn^a ; ^b ; ^{em.bahn@gmail.com} ; Anton Tamtö ; gl^b ; ^c ; ^{tamtoegl@gmail.com} ; John Ellis^b ; William Allison^b ; Peter Fouquet^a ; ^{fouquet@ill.eu}
• 关键词：Graphene ; Ni(111) ; Hydrogenation ; Helium atom scattering
• 刊名：Carbon
• 出版年：2017
• 出版时间：April 2017
• 年：2017
• 卷：114
• 期：Complete
• 页码：504-510
• 全文大小：1474 K
• 卷排序：114

文摘

Using helium-3 atom scattering, we have studied the adsorption kinetics, the structure and the diffusional dynamics of atomic hydrogen on the surface of a graphene monolayer on Ni(111). Diffraction measurements reveal a 4° rotated rectangular hydrogen overstructure. Hydrogen adsorption and desorption exhibit activation barriers of Ea=(89±7)Ea=(89±7) meV and Ed=(1.8±0.2)Ed=(1.8±0.2) eV, respectively. Helium-3 spin-echo measurements showed no decay of the spatial correlation function (or intermediate scattering function) within the time range of the spectrometer. Hence, we are able to set lower limits for a possible hydrogen surface diffusion rate.