title: Barrier inhomogeneities at vertically stacked graphene-based heterostructures.
abstract: The integration of graphene and other atomically flat, two-dimensional materials has attracted much interest and been materialized very recently. An in-depth understanding of transport mechanisms in such heterostructures is essential. In this study, vertically stacked graphene-based heterostructure transistors were manufactured to elucidate the mechanism of electron injection at the interface. The temperature dependence of the electrical characteristics was investigated from 300 to 90 K. In a careful analysis of current-voltage characteristics, an unusual decrease in the effective Schottky barrier height and increase in the ideality factor were observed with decreasing temperature. A model of thermionic emission with a Gaussian distribution of barriers was able to precisely interpret the conduction mechanism. Furthermore, mapping of the effective Schottky barrier height is unmasked as a function of temperature and gate voltage. The results offer significant insight for the development of future layer-integration technology based on graphene-based heterostructures.
authors.affiliation: WPI Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), Tsukuba, Ibaraki 305-0044, Japan. yflin1981@gmail.com TSUKAGOSHI.Kazuhito@nims.go.jp.
authors.forename: Yen-Fu
authors.initials: YF
authors.lastname: Lin
authors.forename: Wenwu
authors.initials: W
authors.lastname: Li
authors.forename: Song-Lin
authors.initials: SL
authors.lastname: Li
authors.forename: Yong
authors.initials: Y
authors.lastname: Xu
authors.forename: Alex
authors.initials: A
authors.lastname: Aparecido-Ferreira
authors.forename: Katsuyoshi
authors.initials: K
authors.lastname: Komatsu
authors.forename: Huabin
authors.initials: H
authors.lastname: Sun
authors.forename: Shu
authors.initials: S
authors.lastname: Nakaharai
authors.forename: Kazuhito
authors.initials: K
authors.lastname: Tsukagoshi