Berlin 2012 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 90: Graphene: Transport incl. Spin Physics and Magnetic Fields II
HL 90.3: Vortrag
Donnerstag, 29. März 2012, 17:30–17:45, ER 270
Graphene Field-Effect Transistors on Hexagonal Boron Nitride Operating at Microwave Frequencies — •Christian Benz1,4, Emiliano Pallecchi2, Andreas C. Betz2, Kenji Watanabe3, Takashi Taniguchi3, Hilbert v. Löhneysen1,4, Bernard Plaçais2, and Romain Danneau1,4 — 1Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Germany — 2Laboratoire Pierre Aigrain, Ecole Normale Supérieure, Paris, France — 3National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan — 4Physikalisches Institut, KIT, Germany
Due to the high charge carrier mobility in graphene, it is an ideal candidate for devices operating at microwave frequency. We have investigated RF graphene field-effect transistors (GFETs) on hexagonal boron nitride. Atomically flat boron nitride crystals are known to increase the mobility by reducing scattering in the graphene. At the same time, the boron nitride serves the purpose of dielectric between graphene sheet and prepatterned gate electrode. Thus, a minimum of charge impurities is introduced to the graphene and current annealing remains possible since the graphene channel is not covered by an oxide. Our GFETs were prepared from exfoliated mono- and bi-layer graphene with a subsequent dry transfer technique onto sapphire, a fully insulating substrate. To improve the flatness, we employed an all-graphene layout with graphene gate fingers. Several devices with gate lengths down to 100 nm were produced and measured. Our GFETs allow for integration into circuits like amplifiers or mixers and are well suited for cryogenic applications.