Intrinsic Electronic Transport Properties of High-Quality Monolayer and Bilayer MoS[subscript 2]

Abstract

We report electronic transport measurements of devices based on monolayers and bilayers of the transition-metal dichalcogenide MoS[subscript 2]. Through a combination of in situ vacuum annealing and electrostatic gating we obtained ohmic contact to the MoS[subscript 2] down to 4 K at high carrier densities. At lower carrier densities, low-temperature four probe transport measurements show a metal–insulator transition in both monolayer and bilayer samples. In the metallic regime, the high-temperature behavior of the mobility showed strong temperature dependence consistent with phonon-dominated transport. At low temperature, intrinsic field-effect mobilities approaching 1000 cm[superscript 2]/(V·s) were observed for both monolayer and bilayer devices. Mobilities extracted from Hall effect measurements were several times lower and showed a strong dependence on density, likely caused by screening of charged impurity scattering at higher densities.