Modeling of Anisotropic Two-Dimensional Materials Monolayer HfS2 and Phosphorene MOSFETs

TL;DR

This study uses quantum transport simulations to compare the performance of HfS2 and phosphorene MOSFETs, revealing the influence of crystal orientation and channel length, with HfS2 showing advantages at shorter scales.

Contribution

It provides a comprehensive analysis of anisotropic 2D material MOSFETs, highlighting the effects of degenerate conduction band valleys and channel orientation on device performance.

Findings

HfS2's performance is less affected by channel orientation than phosphorene.

Phosphorene outperforms HfS2 at 10 nm channel length.

HfS2 can achieve comparable performance to phosphorene at 5 nm channel length.

Abstract

Ballistic transport characteristics of metal-oxide semiconductor field effect transistors (MOSFETs) based on anisotropic two-dimensional (2-D) materials monolayer HfS2 and phosphorene are explored through quantum transport simulations. We focus on the effects of the channel crystal orientation and the channel length scaling on device performances. Especially, the role of degenerate conduction band (CB) valleys in monolayer HfS2 is comprehensively analyzed. Benchmarking monolayer HfS2 with phosphorene MOSFETs, we predict that the effect of channel orientation on device performances is much weaker in monolayer HfS2 than in phosphorene due to the degenerate CB valleys of monolayer HfS2. Our simulations also reveal that, at 10 nm channel length scale, phosphorene MOSFETs outperform monolayer HfS2 MOSFETs in terms of the onstate current. However, it is observed that monolayer HfS2 MOSFETs may offer comparable, but a little bit degraded, device performances as compared with phosphorene MOSFETs at 5 nm channel length.