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

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 mu due to the Schottky barriers at the contacts. For a back-gated two-terminal configuration, we observe mobilities as high as 91 cm(2) V-1 s(-1) which is considerably smaller than 306.5 cm(2) V-1 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. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4799172]