title: Graphene conductance uniformity mapping.
abstract: We demonstrate a combination of micro four-point probe (M4PP) and non-contact terahertz time-domain spectroscopy (THz-TDS) measurements for centimeter scale quantitative mapping of the sheet conductance of large area chemical vapor deposited graphene films. Dual configuration M4PP measurements, demonstrated on graphene for the first time, provide valuable statistical insight into the influence of microscale defects on the conductance, while THz-TDS has potential as a fast, non-contact metrology method for mapping of the spatially averaged nanoscopic conductance on wafer-scale graphene with scan times of less than a minute for a 4-in. wafer. The combination of M4PP and THz-TDS conductance measurements, supported by micro Raman spectroscopy and optical imaging, reveals that the film is electrically continuous on the nanoscopic scale with microscopic defects likely originating from the transfer process, dominating the microscale conductance of the investigated graphene film.
authors.affiliation: Department of Photonics Engineering, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark.
authors.forename: Jonas D
authors.initials: JD
authors.lastname: Buron
authors.forename: Dirch H
authors.initials: DH
authors.lastname: Petersen
authors.forename: Peter
authors.initials: P
authors.lastname: Bøggild
authors.forename: David G
authors.initials: DG
authors.lastname: Cooke
authors.forename: Michael
authors.initials: M
authors.lastname: Hilke
authors.forename: Jie
authors.initials: J
authors.lastname: Sun
authors.forename: Eric
authors.initials: E
authors.lastname: Whiteway
authors.forename: Peter F
authors.initials: PF
authors.lastname: Nielsen
authors.forename: Ole
authors.initials: O
authors.lastname: Hansen
authors.forename: August
authors.initials: A
authors.lastname: Yurgens
authors.forename: Peter U
authors.initials: PU
authors.lastname: Jepsen