Surface Doping and Humidity Sensing of MoS₂ Field-Effect Transistor by Oxygen Plasma Treatment

Abstract

Two-dimensional(2D) semiconducting transition metal dichalcogenides(TMDs) have unique electrical, optical and mechanical properties, and hold great potential for diverse applications such as digital circuits, light harvesting and energy storage. Controlling the electrical properties of TMDs through doping provides an effective approach for sensitive sensing. This paper presents the experimental study of the doping effect of oxygen plasma on molybdenum disulfide(MoS₂). Firstly, the transport characteristics of the MoS₂ field-effect transistor(FET) were investigated and the MoS₂ FET exhibited p-type doping through plasma treatment. Then, the cause of the doping effect was further studied, and the doping effect was attributed to the formation of MoO₃-like defects on the surface of the channel, confirmed by Raman spectroscopy. Finally, the humidity-sensing behavior of the plasma-treated MoS₂ FET was studied. The MoS₂ FET exhibited high sensitivity to humidity because of the increased adsorption centers for water molecules, with the source-drain current change of approximately 54% in humid environment. The work would provide a simple method to modify the electrical properties of TMDs and show potential for low-dimensional chemical sensors.

Keywords

field-effect transistor(FET) / molybdenum disulfide(MoS_2) / oxygen plasma / surface doping / humidity sensing

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Funding

National Natural Science Foundation of China(62005042)