How Good Can Monolayer MoS₂ Transistors Be?

TLDR

Monolayer MoS₂ is a direct‑band‑gap semiconductor with a 1.8 eV gap, and field‑effect transistors fabricated from mechanically exfoliated monolayers have shown promise for next‑generation electronics. The study aims to project the ultimate performance limit of MoS₂ transistors. This is achieved using nonequilibrium Green’s function based quantum‑transport simulations. Simulations predict an ON‑OFF ratio >10¹⁰, subthreshold swing of 60 mV/dec, and negligible short‑channel effects, but the heavier effective mass and lower mobility limit high‑performance use, making MoS₂ attractive for low‑power applications.

Abstract

Monolayer molybdenum disulfide (MoS(2)), unlike its bulk form, is a direct band gap semiconductor with a band gap of 1.8 eV. Recently, field-effect transistors have been demonstrated experimentally using a mechanically exfoliated MoS(2) monolayer, showing promising potential for next generation electronics. Here we project the ultimate performance limit of MoS(2) transistors by using nonequilibrium Green's function based quantum transport simulations. Our simulation results show that the strength of MoS(2) transistors lies in large ON-OFF current ratio (>10(10)), immunity to short channel effects (drain-induced barrier lowering ∼10 mV/V), and abrupt switching (subthreshold swing as low as 60 mV/decade). Our comparison of monolayer MoS(2) transistors to the state-of-the-art III-V materials based transistors, reveals that while MoS(2) transistors may not be ideal for high-performance applications due to heavier electron effective mass (m = 0.45 m(0)) and a lower mobility, they can be an attractive alternative for low power applications thanks to the large band gap and the excellent electrostatic integrity inherent in a two-dimensional system.