Пропозицiя структури графен/Ge(111) на основi дослiдження методом скануючої тунельної мiкроскопiї у надвисокому вакуумi

We report on the 5.5√3 × 5.5√3 − R30 ∘ overlayer superstructure observed by the scanning tunneling microscopy on the Ge(111) surface. It shows pronounced effects of the local density of states leading to the strong dependence of STM images on the bias voltage and some dynamic changes of images at 30...

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Bibliographic Details
Date:2019
Main Authors: Goriachko, A., Melnik, P. V., Nakhodkin, M. G.
Format: Article
Language:English
Ukrainian
Published: Publishing house "Academperiodika" 2019
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Online Access:https://ujp.bitp.kiev.ua/index.php/ujp/article/view/2019131
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Journal Title:Ukrainian Journal of Physics

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Ukrainian Journal of Physics
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Summary:We report on the 5.5√3 × 5.5√3 − R30 ∘ overlayer superstructure observed by the scanning tunneling microscopy on the Ge(111) surface. It shows pronounced effects of the local density of states leading to the strong dependence of STM images on the bias voltage and some dynamic changes of images at 300 K. This overlayer is tentatively interpreted as graphene formed in small submonolayer amounts due to the pyrolysis of hydrocarbon constituents of the residual atmosphere of the vacuum chamber during the annealing of a Ge(111) sample at 900 K. We suggest a model of the graphene/Ge(111)-5.5√3 × 5.5√3 − R30 ∘ heteroepitaxial interface, featuring the reconstructed Ge(111) substrate with no long-range order under the graphene layer, the latter being corrugated due to spatial variations of the interatomic geometry of the Ge(111) and graphene(0001) atomic lattices with extremely large mismatch.