Modulation of ballistic injection velocity in phosphorene nanodevices by bias and confinement effects

Abstract

Atomistic quantum transport simulations are employed to study the electron injection velocity (vinj) and ballistic performance of phosphorene nanoribbon (PNR) field-effect transistors (FETs). We show that PNR bandstructure is immune to quantum confinement effects, which is seen in a rather constant vinj≈2.1 × 107cm/s down to the PNR width of 1.5 nm. Moreover, we demonstrate that the modulation of vinj by gate bias is available only for PNRs wider than 2.1 nm, with the maximum enhancement being 33%. Finally, it is reported that PNR FETs combine high cut-off frequencies above 526 GHz with acceptable bandgap that ranges from 0.7 eV to 1.6 eV in the examined PNR width range, which proves the plausibility of PNRs as channel material for future ultra-scaled high-speed FETs.