How Good Can Monolayer MoS2 Transistors Be?

Abstract

Monolayer molybdenum disulfide (MoS₂), 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 MoS₂ monolayer, showing promising potential for next generation electronics. Here we project the ultimate performance limit of MoS₂ transistors by using nonequilibrium Green’s function based quantum transport simulations. Our simulation results show that the strength of MoS₂ transistors lies in large ON–OFF current ratio (>10¹⁰), 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 MoS₂ transistors to the state-of-the-art III–V materials based transistors, reveals that while MoS₂ transistors may not be ideal for high-performance applications due to heavier electron effective mass (m* = 0.45m₀) 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.