title: Fabrication of quantum-dot devices in graphene.
abstract: We describe our recent experimental results on the fabrication of quantum-dot devices in a graphene-based two-dimensional system. Graphene samples were prepared by micromechanical cleavage of graphite crystals on a SiO2/Si substrate. We performed micro-Raman spectroscopy measurements to determine the number of layers of graphene flakes during the device fabrication process. By applying a nanofabrication process to the identified graphene flakes, we prepared a double-quantum-dot device structure comprising two lateral quantum dots coupled in series. Measurements of low-temperature electrical transport show the device to be a series-coupled double-dot system with varied interdot tunnel coupling, the strength of which changes continuously and non-monotonically as a function of gate voltage.
authors.affiliation: International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Moriyama
authors.affiliation: Faculty of Engineering, Gunma University, Kiryu, Gunma 376-8515, Japan.
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Morita
authors.affiliation: Nanotechnology Innovation Center, NIMS, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan.
authors.forename: Eiichiro
authors.initials: E
authors.lastname: Watanabe
authors.affiliation: Nanotechnology Innovation Center, NIMS, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan.
authors.forename: Daiju
authors.initials: D
authors.lastname: Tsuya
authors.affiliation: Advanced Nano Materials Laboratory, NIMS, 3-13 Sakura, Tsukuba, Ibaraki 305-0003, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Uji
authors.affiliation: Advanced Device Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: Maki
authors.initials: M
authors.lastname: Shimizu
authors.affiliation: Advanced Device Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Ishibashi
keywords: double quantum dots; graphene; quantum dots; single-electron transport