Phonon-limited performance of single-layer, single-gate black phosphorus n- and p-type field-effect transistors

Phosphorene is a novel 2-D material with a direct band gap and a high electron/hole mobility, which makes it attractive for logic applications. The theoretical investigations of such devices have so far lacked either one or both key ingredients of realistic simulations: a full-band description of the electronic states and the consideration of electron-phonon scattering. In this paper we present the first ab-initio quantum transport simulations of phosphorene transistors accounting for these effects. We show that the DOS bottleneck does not limit the performance of phosphorene FETs, that the armchair configuration takes advantage of its lower effective mass and higher mobility at gate lengths above 10 nm, but that these properties become an obstacle at shorter gate lengths. We also demonstrate that phosphorene FETs with 10 nm gate length outperform MoS₂, regardless of the channel orientation.