title: Standardization of surface potential measurements of graphene domains.
abstract: We compare the three most commonly used scanning probe techniques to obtain a reliable value of the work function in graphene domains of different thickness. The surface potential (SP) of graphene is directly measured in Hall bar geometry via a combination of electrical functional microscopy and spectroscopy techniques, which enables calibrated work function measurements of graphene domains in ambient conditions with values Φ1LG ~4.55 ± 0.02 eV and Φ2LG ~ 4.44 ± 0.02 eV for single- and bi-layer, respectively. We demonstrate that frequency-modulated Kelvin probe force microscopy (FM-KPFM) provides more accurate measurement of the SP than amplitude-modulated (AM)-KPFM. The discrepancy between experimental results obtained by different techniques is discussed. In addition, we use FM-KPFM for contactless measurements of the specific components of the device resistance. We show a strong non-Ohmic behavior of the electrode-graphene contact resistance and extract the graphene channel resistivity.
authors.affiliation: National Physical Laboratory, Teddington, UK .
authors.forename: Vishal
authors.initials: V
authors.lastname: Panchal
authors.forename: Ruth
authors.initials: R
authors.lastname: Pearce
authors.forename: Rositza
authors.initials: R
authors.lastname: Yakimova
authors.forename: Alexander
authors.initials: A
authors.lastname: Tzalenchuk
authors.forename: Olga
authors.initials: O
authors.lastname: Kazakova
mesh_terms: D006108:Graphite / Q000737:chemistry*; D008422:Materials Testing / Q000379:methods* / Q000592:standards; D020527:Microscopy, Scanning Probe / Q000379:methods* / Q000592:standards; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure*; D013499:Surface Properties
chemical_list: D006108:Graphite