Performance Comparison of 2D Mono-Elemental (X-enes) Armchair Nanoribbon Schottky Barrier Field Effect Transistors

In this work, comprehensive analysis of Schottky barrier (SB) field effect transistors (FETs) having 2D mono-elemental (X-enes) nanoribbon (NR) with width of 10 dimers along the armchair direction as a channel material has been carried out. The multi-scale approach used for simulating the hydrogen passivated X-ene NR SBFETs consists of density functional theory (DFT), Wannier function based tight binding and the non-equilibrium Green's Function formalism (NEGF). The derived bandgaps for X-enes such as graphene, germanene, phosphorene and silicene are 1.27, 0.379, 1.036 and 0.431 eV respectively. To incorporate the effect of band-bending at the metal-X-ene interface the modification in the conventional multi-scale approach has also been proposed. To mimic the effect of band bending at metal-X-ene interface the schemes proposed in the model are, addition of equivalent channel potential energy in the Hamiltonian matrix and the addition of fixed charges in initial charge profile. Further, the impact of SB width, Fermi level pinning and the scattering on the device performance has also been explored. The results show that the on-state drive current-to-off-state leakage current ratio in the case of graphene and phosphorene SBFETs is up-to the order ∼10
⁷
whereas for silicene and germanene SBFETs it is in the order of ∼10
³
.