Rendering high charge density of states in ionic liquid-gated MoS ₂ transistors

We investigated high charge density of states (DOS) in the bandgap of MoS₂ nanosheets with variable temperature measurements on ionic liquid-gated MoS₂ transistors. The thermally activated charge transport indicates that the electrical current in the two-dimensional MoS ₂ nanosheets under high charge density state follows the Meyer-Neldel rule. The achieved high charge density allows the surface DOS estimation of MoS₂ nanosheets, which have distinct peaks at 0.135 and 0.145 eV below the conduction band, with the largest DOS values of 9.75 × 10 ¹⁴ and 4.33 × 10¹⁴ cm^-2 eV^-1, respectively. This may represent the monolayer MoS₂ nanosheets that coexist with the MoS₂ multilayer in the channel area of the ionic liquid-gated MoS₂ transistors.