title: Carrier type inversion in quasi-free standing graphene: studies of local electronic and structural properties.
abstract: We investigate the local surface potential and Raman characteristics of as-grown and ex-situ hydrogen intercalated quasi-free standing graphene on 4H-SiC(0001) grown by chemical vapor deposition. Upon intercalation, transport measurements reveal a change in the carrier type from n- to p-type, accompanied by a more than three-fold increase in carrier mobility, up to μh ≈ 4540 cm(2) V(-1) s(-1). On a local scale, Kelvin probe force microscopy provides a complete and detailed map of the surface potential distribution of graphene domains of different thicknesses. Rearrangement of graphene layers upon intercalation to (n + 1)LG, where n is the number of graphene layers (LG) before intercalation, is demonstrated. This is accompanied by a significant increase in the work function of the graphene after the H2-intercalation, which confirms the change of majority carriers from electrons to holes. Raman spectroscopy and mapping corroborate surface potential studies.
authors.affiliation: 1] National Physical Laboratory, Teddington, TW11 0LW, United Kingdom [2] Advanced Technology Institute, University of Surrey, Guildford, Surrey, GU2 7XH, UK.
authors.forename: Christos
authors.initials: C
authors.lastname: Melios
authors.affiliation: National Physical Laboratory, Teddington, TW11 0LW, United Kingdom.
authors.forename: Vishal
authors.initials: V
authors.lastname: Panchal
authors.affiliation: National Physical Laboratory, Teddington, TW11 0LW, United Kingdom.
authors.forename: Cristina E
authors.initials: CE
authors.lastname: Giusca
authors.affiliation: Institute of Electronic Materials Technology, Wólczyńska 133, 01-919 Warsaw, Poland.
authors.forename: Włodek
authors.initials: W
authors.lastname: Strupiński
authors.affiliation: Advanced Technology Institute, University of Surrey, Guildford, Surrey, GU2 7XH, UK.
authors.forename: S Ravi P
authors.initials: SR
authors.lastname: Silva
authors.affiliation: National Physical Laboratory, Teddington, TW11 0LW, United Kingdom.
authors.forename: Olga
authors.initials: O
authors.lastname: Kazakova