Interface between Graphene and SrTiO3(001) Investigated by Scanning Tunneling Microscopy and Photoemission

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• 作者：Horacio Coy-Diaz ; Rafik Addou ; Matthias Batzill
• 刊名：Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：October 10, 2013
• 年：2013
• 卷：117
• 期：40
• 页码：21006-21013
• 全文大小：486K
• 年卷期：v.117,no.40(October 10, 2013)
• ISSN：1932-7455

文摘

Graphene, grown by chemical vapor deposition, is transferred onto Nb-doped SrTiO₃(001) surface and the interface properties are characterized by scanning tunneling microscopy and photoemission spectroscopy. Charge doping of graphene changes from n- to p-type with vacuum annealing and correspondingly opposite space charge regions are observed in SrTiO₃ substrate. Formation of an ordered surface reconstruction of the SrTiO₃ substrate underneath the graphene is observed. The surface restructuring can be measured in scanning tunneling microscopy because the graphene closely follows to the substrate topography. This causes at the atomic-level a wavy graphene morphology on the SrTiO₃ (001)-c(6 脳 2) surface reconstruction. Prolonged high temperature (above 700 掳C) vacuum annealing causes formation of hexagonal holes with 鈥榓rmchair鈥?edges in the graphene and an eventual disappearance of the graphene. Etching of the graphene is assumed to be caused by reaction with released substrate oxygen.