DFT Performance Analysis of Graphene Nanoribbon FET with Gate Stack for Low Power Applications

This article presents the improved device performance of graphene nanoribbon field effect transistor with novel structure. In this proposed structure, number of carbon atoms are varied along armchair graphene nanoribbon (AGN) width (n), across the channel. The channel material is developed with gate stack approach. Moreover, the carrier transport using huckel extended (HE) model-based density functional theory (DFT) is studied. The rise in the value of 'n' from 4 to 8 in the channel material enhances the ON current (ION), reduces OFF current (IOFF), improves the switching ratio, and reduces threshold voltage (Vth) 29 %, results reduced drain induced barrier lowering (DIBL) in A8 device (GS-GNFET with AGN (n = 8) in channel material) as compared with A4 device having (GS-GNFET with AGN (n = 8) in channel material). The device density of states (DDOS) analysis confirms higher electron occupation and better performance of A8 device compared to A4 device model. The tight-binding Hamiltonian matrix is solved using the HE model and a semi-empirical calculator. A 33 % improvement in ON current and a 76 % reduction in OFF current have been recorded in our proposed GS-GNFET device model over conventional GNRFET. Moreover, the A8 device has a very low value of static power (1.69 × 10 – 13 watt) compared to pre-established experimental data recorded through literature survey.