title: "Freeing" Graphene from Its Substrate: Observing Intrinsic Velocity Saturation with Rapid Electrical Pulsing.
abstract: Rapid (nanosecond-scale) electrical pulsing is used to study drift-velocity saturation in graphene field-effect devices. In these experiments, high-field pulses are utilized to drive graphene's carriers on time scales much faster than that on which energy loss to the underlying substrate can occur, thereby allowing the observation of the highest saturation velocities reported to date. In a dramatic departure from the behavior exhibited by conventional metals and semiconductors, as the electron or hole density is reduced toward the charge-neutrality point, the drift velocity is found to reach values comparable to the Fermi velocity itself. Corresponding current densities are as large as 10(9) A/cm(2), similar to the values reported for carbon nanotubes and for graphene-on-diamond transistors. In essence, our approach of rapid pulsing allows us to "free" graphene from the deleterious influence of its substrate, revealing a pathway to achieve the superior electrical performance promised by this material. The usefulness of this approach is not merely limited to graphene but should extend also to a broad variety of two-dimensional semiconductors.
authors.affiliation: Department of Electrical Engineering, University at Buffalo, the State University of New York , Buffalo, New York 14260-1900, United States.
authors.forename: H
authors.initials: H
authors.lastname: Ramamoorthy
authors.affiliation: Department of Physics, King Mongkut's Institute of Technology Ladkrabang , Bangkok 10520, Thailand.
authors.forename: R
authors.initials: R
authors.lastname: Somphonsane
authors.affiliation: Department of Electrical Engineering, University at Buffalo, the State University of New York , Buffalo, New York 14260-1900, United States.
authors.forename: J
authors.initials: J
authors.lastname: Radice
authors.affiliation: Department of Electrical Engineering, University at Buffalo, the State University of New York , Buffalo, New York 14260-1900, United States.
authors.forename: G
authors.initials: G
authors.lastname: He
authors.affiliation: Department of Physics, University at Buffalo, the State University of New York , Buffalo, New York 14260-1500, United States.
authors.forename: C-P
authors.initials: CP
authors.lastname: Kwan
authors.affiliation: Department of Electrical Engineering, University at Buffalo, the State University of New York , Buffalo, New York 14260-1900, United States.|Graduate School of Advanced Integration Science, Chiba University , 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan.
authors.forename: J P
authors.initials: JP
authors.lastname: Bird
keywords: Velocity saturation; graphene; hot carriers; thermal effects in nanodevices; transient transport