Rendering High Charge Density of States in Ionic Liquid-Gated MoS₂ Transistors

Abstract

We investigated high charge density of states (DOS) in the bandgap of MoS 2 nanosheets with variable temperature measurements on ionic liquid-gated MoS 2 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 MoS 2 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 × 10 14 cm –2 eV –1, respectively. This may represent the monolayer MoS 2 nanosheets that coexist with the MoS 2 multilayer in the channel area of the ionic liquid-gated MoS 2 transistors.