Monolithically Patterned Wide–Narrow–Wide All-Graphene Devices

Dincer Unluer, Frank Tseng, Avik W. Ghosh, and Mircea R. Stan, IEEE Transactions on Nanotechnology , 10 (5) :931-939 (2010).
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Abstract

We investigate theoretically the performance advantages of all-graphene nanoribbon field-effect transistors (GNRFETs) whose channel and source/drain (contact) regions are patterned monolithically from a 2-D single sheet of graphene. In our simulated devices, the source/drain and interconnect regions are composed of wide GNR sections that are semimetallic, while the channel regions consist of narrow GNR sections that open semiconducting bandgaps. Our simulation employs a fully atomistic model of the device, contact, and interfacial regions using tight-binding theory. The electronic structures are coupled with a self-consistent 3-D Poisson’s equation to capture the nontrivial contact electrostatics, along with a quantum kinetic formulation of transport based on nonequilibrium Green’s functions. Although we only consider a specific device geometry, our results establish several general performance advantages of such monolithic devices (besides those related to fabrication and patterning), namely, the improved electrostatics, suppressed short-channel effects, and Ohmic contacts at the narrow-to-wide interfaces.