Nonvolatile n-Type Doping and Metallic State in Multilayer-MoS<sub>2</sub> Induced by Hydrogenation Using Ionic-Liquid Gating.

Guo, Wenxuan; Li, Mengge; Wu, Xiaoxiang; Liu, Yali; Ou, Tianjian; Xiao, Cong; Qiu, Zhanjie; Zheng, Yuan et al. · Nano Lett · 2022

basic_science · Level V

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Abstract

Manipulation of the carrier density of layered transition-metal dichalcogenides (TMDs) is of fundamental significance for a wide range of electronic and optoelectronic applications. Herein, we applied the ionic-liquid-gating (ILG) method to inject the smallest ions, H<sup>+</sup>, into layered MoS<sub>2</sub> to manipulate its carrier concentration. The measurements demonstrate that the injection of H<sup>+</sup> realizes a nonvolatile n-type doping and metallic state in multilayer-MoS<sub>2</sub> with a concentration of injection electron of ∼1.08 × 10<sup>13</sup> cm<sup>-2</sup> but has no effect on monolayer-MoS<sub>2</sub>, which clearly reveals that the H<sup>+</sup> is injected into the interlayer of MoS<sub>2</sub>, not in the crystal lattice. The H<sup>+</sup>-injected multilayer-MoS<sub>2</sub> was then used as the contact electrodes of a monolayer-MoS<sub>2</sub> field effect transistor to improve the contact quality, and its performance has been enhanced. Our work deepens the understanding of the ILG technology and extends its application in TMDs.