  Molybdenum disulfide is considered as one of the most promising
two-dimensional semiconductors for electronic and optoelectronic device
applications. So far, the charge transport in monolayer molybdenum disulfide is
dominated by extrinsic factors such as charged impurities, structural defects
and traps, leading to much lower mobility than the intrinsic limit. Here, we
develop a facile low-temperature thiol chemistry to repair the sulfur vacancies
and improve the interface, resulting in significant reduction of the charged
impurities and traps. High mobility greater than 80cm2 V-1 s-1 is achieved in
backgated monolayer molybdenum disulfide field-effect transistors at room
temperature. Furthermore, we develop a theoretical model to quantitatively
extract the key microscopic quantities that control the transistor
performances, including the density of charged impurities, short-range defects
and traps. Our combined experimental and theoretical study provides a clear
path towards intrinsic charge transport in two-dimensional dichalcogenides for
future high-performance device applications.
