title: Direct Determination of Field Emission across the Heterojunctions in a ZnO/Graphene Thin-Film Barristor.
abstract: Graphene barristors are a novel type of electronic switching device with excellent performance, which surpass the low on-off ratios that limit the operation of conventional graphene transistors. In barristors, a gate bias is used to vary graphene's Fermi level, which in turn controls the height and resistance of a Schottky barrier at a graphene/semiconductor heterojunction. Here we demonstrate that the switching characteristic of a thin-film ZnO/graphene device with simple geometry results from tunneling current across the Schottky barriers formed at the ZnO/graphene heterojunctions. Direct characterization of the current-voltage-temperature relationship of the heterojunctions by ac-impedance spectroscopy reveals that this relationship is controlled predominantly by field emission, unlike most graphene barristors in which thermionic emission is observed. This governing mechanism makes the device unique among graphene barristors, while also having the advantages of simple fabrication and outstanding performance.
authors.affiliation: Department of Chemical Engineering and Materials Science, University of California , Davis, California 95616-5294, United States.
authors.forename: Edmund M
authors.initials: EM
authors.lastname: Mills
authors.affiliation: Thin Film Materials Research Group, Korea Research Institute of Chemical Technology (KRICT) , Yuseong P.O. Box 107, Daejeon 305-600, Republic of Korea.|Department of Physics, Sungkyunkwan University , 2066 Seoburo, Jangan-gu, Suwon, Gyeonggi-do 440-746, Republic of Korea.
authors.forename: Bok Ki
authors.initials: BK
authors.lastname: Min
authors.affiliation: Department of Chemical Engineering and Materials Science, University of California , Davis, California 95616-5294, United States.
authors.forename: Seong K
authors.initials: SK
authors.lastname: Kim
authors.affiliation: Thin Film Materials Research Group, Korea Research Institute of Chemical Technology (KRICT) , Yuseong P.O. Box 107, Daejeon 305-600, Republic of Korea.
authors.forename: Seong Jun
authors.initials: SJ
authors.lastname: Kim
authors.affiliation: Thin Film Materials Research Group, Korea Research Institute of Chemical Technology (KRICT) , Yuseong P.O. Box 107, Daejeon 305-600, Republic of Korea.
authors.forename: Min-A
authors.initials: MA
authors.lastname: Kang
authors.affiliation: Thin Film Materials Research Group, Korea Research Institute of Chemical Technology (KRICT) , Yuseong P.O. Box 107, Daejeon 305-600, Republic of Korea.
authors.forename: Wooseok
authors.initials: W
authors.lastname: Song
authors.affiliation: Thin Film Materials Research Group, Korea Research Institute of Chemical Technology (KRICT) , Yuseong P.O. Box 107, Daejeon 305-600, Republic of Korea.
authors.forename: Sung
authors.initials: S
authors.lastname: Myung
authors.affiliation: Thin Film Materials Research Group, Korea Research Institute of Chemical Technology (KRICT) , Yuseong P.O. Box 107, Daejeon 305-600, Republic of Korea.
authors.forename: Jongsun
authors.initials: J
authors.lastname: Lim
authors.affiliation: Thin Film Materials Research Group, Korea Research Institute of Chemical Technology (KRICT) , Yuseong P.O. Box 107, Daejeon 305-600, Republic of Korea.
authors.forename: Ki-Seok
authors.initials: KS
authors.lastname: An
authors.affiliation: Department of Chemical Engineering and Materials Science, University of California , Davis, California 95616-5294, United States.|Graphene Research Institute, Department of Nanoscience and Technology, Sejong University , 98 Gunja-dong, Gwangjin-gu, Seoul 143-747, Republic of Korea.
authors.forename: Jongwan
authors.initials: J
authors.lastname: Jung
authors.affiliation: Department of Chemical Engineering and Materials Science, University of California , Davis, California 95616-5294, United States.
authors.forename: Sangtae
authors.initials: S
authors.lastname: Kim
keywords: ac impedance spectroscopy; barristors; field emission; graphene; schottky barriers