In this paper, we investigate the electrical behavior of transistors based on a vertical graphene-hexagonal boron nitride (hBN) heterostructure, using atomistic multiphysics simulations based on density-functional theory and non-equilibrium Green’s function formalism. We show that the hBN current-blocking layer is effective and allows modulation of the current by five orders of magnitude, confirming experimental results. We also highlight—through accurate numerical calculations and simpli- fied analytical modeling—some intrinsic limitations of vertical heterostructure transistors. We show that the overlap between gate contacts and source/drain leads screens the electric field induced by the gates and is responsible for the excessive degradation of the sub-threshold swing, the ION/IOFF ratio, and the cut-off frequency.

Very Large Current Modulation in Vertical Heterostructure Graphene/hBN Transistors

FIORI, GIANLUCA;IANNACCONE, GIUSEPPE
2013

Abstract

In this paper, we investigate the electrical behavior of transistors based on a vertical graphene-hexagonal boron nitride (hBN) heterostructure, using atomistic multiphysics simulations based on density-functional theory and non-equilibrium Green’s function formalism. We show that the hBN current-blocking layer is effective and allows modulation of the current by five orders of magnitude, confirming experimental results. We also highlight—through accurate numerical calculations and simpli- fied analytical modeling—some intrinsic limitations of vertical heterostructure transistors. We show that the overlap between gate contacts and source/drain leads screens the electric field induced by the gates and is responsible for the excessive degradation of the sub-threshold swing, the ION/IOFF ratio, and the cut-off frequency.
Fiori, Gianluca; S., Bruzzone; Iannaccone, Giuseppe
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11568/256953
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