Letter abstract
Nature Nanotechnology 3, 654 - 659 (2008)
Published online: 21 September 2008 | doi:10.1038/nnano.2008.268
Subject Category: Electronic properties and devices
Current saturation in zero-bandgap, top-gated graphene field-effect transistors
Inanc Meric1, Melinda Y. Han2, Andrea F. Young3, Barbaros Ozyilmaz3,4, Philip Kim3 & Kenneth L. Shepard1
Abstract
The novel electronic properties of graphene1, 2, 3, 4, including a linear energy dispersion relation and purely two-dimensional structure, have led to intense research into possible applications of this material in nanoscale devices. Here we report the first observation of saturating transistor characteristics in a graphene field-effect transistor. The saturation velocity depends on the charge-carrier concentration and we attribute this to scattering by interfacial phonons in the SiO2 layer supporting the graphene channels5, 6. Unusual features in the current–voltage characteristic are explained by a field-effect model and diffusive carrier transport in the presence of a singular point in the density of states. The electrostatic modulation of the channel through an efficiently coupled top gate yields transconductances as high as 150 
S m-1 despite low on–off current ratios. These results demonstrate the feasibility of two-dimensional graphene devices for analogue and radio-frequency circuit applications without the need for bandgap engineering.
- Department of Electrical Engineering, Columbia University, New York 10027, USA
- Department of Applied Physics and Applied Mathematics, Columbia University, New York 10027, USA
- Department of Physics, Columbia University, New York 10027, USA
- Present Address: Department of Physics, NUS 2 Science Drive 3, 117542 Singapore
Correspondence to: Kenneth L. Shepard1 e-mail: shepard@ee.columbia.edu
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