A fast method to analyze and characterize the graphene nanoribbon FET by non-equilibrium Green's function

Abstract

In this paper, based on the simple Pz orbital model, the energy diagram of armchair and zigzag graphene nanoribbons (A-GNR & Z-GNR) are studied by considering the first and third nearest neighbors (FNN & TNN). Then, we applied the Non-Equilibrium Green Function method to calculate the conduction in A-GNR. Thereafter, we analyzed the single gated GNRFET in real space provided that under any Vgs the energy of all the atoms within the channel remains the same (qVgs) and consequently, solving Poisson's equation is not needed anymore. The numerical calculation of the self-energy matrices is done based on two approaches, where the same result is obtained but different CPU times consumed. Therefore, one of the advantages of our approach is considerably lower consuming time of calculation. The number of atoms across the width of the channel nanoribbon is chosen so that the channel behaves as a semiconductor. However, for the reservoirs (source and drain) the number of atoms within their widths makes them metallic ribbons. The results of applying TNN in comparison with those of FNN show that TNN is more accurate and reliable. Finally, we can conclude that in A-GNRFET tunneling component of the current from reservoir to the channel is significant.