Comprehensive understanding of intrinsic mobility and sub-10 nm quantum transportation in Ga2SSe monolayer

Two-dimensional chalcogenides could play an important role in solving the short channel effect and extending Moore's law in the post-Moore era due to their excellent performances in the spintronics and optoelectronics fields. In this paper, based on theoretical calculations combining density functional theory and non-equilibrium Green's function, we have systematically explored the intrinsic mobility in the Ga2SSe monolayer and quantum transport properties of sub-10 nm Ga2SSe field-effect transistors (FET). Interestingly, the Ga2SSe monolayer presents high intrinsic electron mobility up to 104 cm2 (V s)-1. It is highlighted that the intrinsic mobility in the Ga2SSe monolayer is significantly restrained by phonon scattering, where the out-of-plane acoustic mode and high-frequency optic phonon mode are found predominantly coupled with the electrons. As a result, the n-type doping sub-10 nm Ga2SSe FETs represent distinguished transport properties. In particular, even the gate length is shortened to 3 nm, the on-state current, delay time and power consumption of the n-type doping Ga2SSe FET along the armchair direction can reach the International Technology Roadmap for Semiconductor industry standards for high-performance requirements. Our present study paves the way for the application of Ga2SSe monolayers in ultra-small sized FETs in the post-silicon era.