Wetting Transparency-Induced Enhancement of Moisture Stability in Monolayer Transition Metal Dichalcogenides

2D materials are considered promising candidates for next-generation semiconductor devices. However, their high surface-to-volume ratio makes them highly susceptible to environmental degradation, particularly in the presence of moisture. Monolayer n-type transition metal dichalcogenides (TMDCs), synthesized via chemical vapor deposition (CVD), are especially vulnerable to degradation under humid conditions. In this study, H₂O adsorption is controlled by utilizing the wetting transparency of TMDCs and tuning the surface energy of the supporting substrate toward hydrophobicity. Substrates with varying surface energies are employed, and the ambient stability of devices is systematically assessed using optical and electrical measurements. It is found that monolayer TMDCs retain stable structural and electronic properties even under extreme conditions (relative humidity > 90%, temperatures up to 500 K). This demonstrates that substrate surface engineering is an effective strategy to enhance the environmental reliability of TMDC-based electronic devices.