Intrinsic carrier mobility of multi-layered MoS2 field-effect transistors on SiO2

Abstract

By fabricating and characterizing multi-layered MoS₂-based field-effect transistors in a four terminal configuration, we demonstrate that the two terminal-configurations tend to underestimate the carrier mobility μ due to the Schottky barriers at the contacts. For a back-gated two-terminal configuration, we observe mobilities as high as $91\hspace{0.17em}{\text{cm}}^2\hspace{0.17em}{\mathrm{V}}^{-1}\hspace{0.17em}{\mathrm{s}}^{-1}$ which is considerably smaller than $306.5\hspace{0.17em}{\text{cm}}^2{\hspace{0.17em}\mathrm{V}}^{-1}\hspace{0.17em}{\mathrm{s}}^{-1}$ as extracted from the same device when using a four-terminal configuration. This indicates that the intrinsic mobility of MoS₂ on SiO₂ is significantly larger than the values previously reported, and provides a quantitative method to evaluate the charge transport through the contacts.