Dresden 2009 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 8: Postersession Transport: Graphene and Carbon Nanotubes
TT 8.4: Poster
Montag, 23. März 2009, 13:00–16:45, P1B
Microwave graphene nano-transistors — Andreas Betz, •Emiliano Pallecchi, Julien Chaste, Takis Kontos, Gwendal Fève, Jean-Marc Berroir, and Bernard Plaçais — Laboratoire Pierre Aigrain, Ecole Normale Supérieure, 24 rue Lhomond, 75005 Paris, France.
We report on microwave characterization of graphene nano-transistors. The samples consist of top-gated graphene flakes connected to source and drain electrodes. We performed room temperature transmission measurements using an RF probe station from which we can access both the transconductance and the gate capacitance. We observed mobility as large as 7800 cm2/Vs, while the maximum transconductance was 2.5 mS/µm at DC and 0.5 mS/µm at gigahertz frequency. The gate capacitance at the gate voltage corresponding to the maximum transconductance is about 0.9 fF (100 nm gate length). Our measurements show that graphene nano-transistors are characterized by a large transit frequency fT = gm/2πCg on the order of 1 THz for a gate length of 100 nm (best device measured). We finally discuss their possible sensitivity as fast charge detectors.