A Functional Study of a Bilayer Graphene Nanoribbon FET With Four Different Gate Insulators

Bilayer graphene like monolayer graphene has a zero bandgap. To use as a channel material of FETs, its band gap should be open which is crucial for its application in logic circuits. Several methods have been developed to open the band gap in graphene. The simple way is cutting graphene into ribbons. In this paper, a novel structure for a dual-gated bilayer graphene nanoribbon field-effect transistor (BLGNRFET) is suggested, which merges the advantages of high and low dielectric constants. The gate insulator of FET is divided into four parts with different dielectric materials, so the proposed device is called FDI-BLGNRFET. All of the possible state of gate insulators which can happen for these four different parts are surveyed. The simulations are conducted by means of the self-consistent solution of the Poisson and Schrödinger equations within the NonEquilibrium Green Function (NEGF) and a tightbinding Hamiltonian, in the real space approach. Regarding to the results, for the proposed FDI-BLGNRFET with K1 = K2 = 25 and K3 = K4 = 3.9, the maximum I
_ON
/I
_OF
F ratio 119% higher than the conventional BLGNRFET is achieved which is still remains inadequate for getting an acceptable (ION/IOF F ) ratio in CMOS performance.