Asymmetric Junctions in Metallic–Semiconducting–Metallic Heterophase MoS2

Abstract

Symmetry of the source–channel and drain–channel junction is a unique property of a metal-oxide-semiconductor field effect transistor (MOSFET), which needs to be preserved while realizing sub-decananometer channel length devices using advanced technology. Employing experimental-findings-driven atomistic modeling techniques, we demonstrate that such symmetry might not be preserved in an atomically thin phase-engineered MoS2-based MOSFET. It originates from the two distinct atomic patterns at phase boundaries ( $\beta $ and $\beta $ *) when the semiconducting phase (channel) is sandwiched between the two metallic phases (source and drain). We develop a geometrically optimized atomic model of two independent heterophase structures comprising $\beta $ and $\beta $ * interfaces and study their electrical characteristics using density functional theory-nonequilibriumGreen’s function formalism. We further study the effect of semiconductor doping on the transmission of those planar devices and show that irrespective of the doping concentration, these heterophase structures exhibit asymmetric barrier heights. Our findings could be useful for designing integrated circuits using such advanced transistors.