Quasi-free-standing epitaxial graphene on SiC (0001) by fluorine intercalation from a molecular source.

Wong, Swee Liang; Huang, Han; Wang, Yuzhan; Cao, Liang; Qi, Dongchen; Santoso, Iman; Chen, Wei; Wee, Andrew Thye Shen · ACS Nano · 2011

basic_science · Level V

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Abstract

We demonstrated a novel method to obtain charge neutral quasi-free-standing graphene on SiC (0001) from the buffer layer using fluorine from a molecular source, fluorinated fullerene (C(60)F(48)). The intercalated product is stable under ambient conditions and resistant to elevated temperatures of up to 1200 °C. Scanning tunneling microscopy and spectroscopy measurements are performed for the first time on such quasi-free-standing graphene to elucidate changes in the electronic and structural properties of both the graphene and interfacial layer. Novel structures due to a highly localized perturbation caused by the presence of adsorbed fluorine were produced in the intercalation process and investigated. Photoemission spectroscopy is used to confirm these electronic and structural changes.