Quantum Transport Simulation of Sub-1-nm Gate Length Monolayer MoS2 Transistors

Sub-1-nm gate length MoS_2 transistors have been experimentally fabricated, but their device performance limit remains elusive. Herein, we explore the performance limits of the sub-1-nm gate length monolayer (ML) MoS_2 transistors through ab initio quantum transport simulations. Our simulation results demonstrate that, through appropriate doping and dielectric engineering, the sub-1-nm devices can meet the requirement of extended 'ITRS'(International Technology Roadmap for Semiconductors) L_g=0.34 nm. Following device optimization, we achieve impressive maximum on-state current densities of 409 μ A / μ m for n-type and 800 μ A / μ m for p-type high-performance (HP) devices, while n-type and p-type low-power (LP) devices exhibit maximum on-state current densities of 75 μ A / μ m and 187 μ A / μ m, respectively. We employed the Wentzel-Kramer-Brillouin (WKB) approximation to explain the physical mechanisms of underlap and spacer region optimization on transistor performance. The underlap and spacer regions primarily influence the transport properties of sub-1-nm transistors by respectively altering the width and body factor of the potential barriers. Compared to ML MoS_2 transistors with a 1 nm gate length, our sub-1-nm gate length HP and LP ML MoS_2 transistors exhibit lower energy-delay products. Hence the sub-1-nm gate length transistors have immense potential for driving the next generation of electronics.