▎ 摘　　要

Owing to the superior stability and suitable bandgap, the two-dimensional (2D) IV-V semiconductors are pro-mising candidates for nanoelectronic applications and have attracted increasing attentions more recently. Inspired by the experimental fabrication of 2D IV-V semiconductor based transistor devices, we have systematically investigated the electron transport properties of the monolayered IV-V semiconductors by using density functional theory combined with non-equilibrium Green's function. Our calculations revealed that the SiP has superior electrical transport to the GeP, while the former has larger bandgap compared to the latter. This is attributed to the fact that the J-V behaviors are dependent on both bandgap and the coupling of its two electrodes. Furthermore, we have demonstrated that great improvement on electron transport can be achieved by using graphene contact, leading to six times enhancement on the current density. The detailed physical mechanism is the carrier injection significantly lifts the density of states of the nanodevice and therefore improve the J-V characteristics. Our theoretical investigation and computational design could be helpful to the potential application of the 2D IV-V semiconductors for nanoelectronic devices in future.