As a potential semiconductor material for various applications, the quality of Molybdenum disulfide (MoS2) and its control are the subject of substantial interest. Intrinsic defects are common phenomena in monolayer MoS2 which significantly impacts its properties. Among these, the most notable are sulfur vacancies. Understanding the stability and functionality of MoS2 is critical due to its susceptibility to oxidative environments and treatments.
In this thesis, we analyzed humidity effects on electrical properties of monolayer MoS2 fieldeffect transistors to understand the water molecule absorption mechanism on monolayer MoS2 devices. The predominant effect of humidity is the modulation of the Schottky barriers at the MoS2 metal electrode contact, according to our findings.
We also investigated the oxygen plasma impact on monolayer MoS2. We used Atomic Force Microscope (AFM) and Photoluminescence images to investigate the structural change. In addition, we also analyzed their influence on electrical characteristics of the monolayer MoS2 based fieldeffect transistors. We found the way to control the doping effect on monolayer MoS2 by modifying the plasma condition. The 𝑛/𝑝 doping induce in monolayer MoS2 due to the generation of Sulfur vacancies (𝑛 doping) and passivation of Sulfur vacancies (𝑝 doping).