Soft Sputtering of Large-Area 2D MoS2 Layers Using Isolated Plasma Soft Deposition for Humidity Sensors

2D transition-metal dichalcogenides are emerging as key materials for next-generation semiconductor technologies owing to their tunable bandgaps, high carrier mobilities, and exceptional surface-to-volume ratios. Among them, molybdenum disulfide (MoS2) has garnered significant attention. However, scalable wafer-level deposition methods that enable uniform layer-controlled synthesis remain a critical challenge. In this paper, a novel fabrication approach-isolated plasma soft deposition (IPSD) followed by sulfurization-for the scalable production of 2D MoS2 with precise layer control is introduced. The IPSD system employs a scanning-based deposition method combined with plasma surface pretreatment, achieving large-area, high-quality 2D MoS2 layers. Comprehensive characterizations using Raman, UV-vis, and photoluminescence spectroscopy, and transmission electron microscopy confirmed the successful synthesis of crystalline mono- to tetralayer 2D MoS2 on 6-inch SiO2/Si substrates. Furthermore, respiration sensors fabricated using the IPSD-grown 2D MoS2 layers demonstrated fast response times (approximate to 1 s) and high response to relative humidity levels between 30% and 60%. This study offers significant advancements in the scalable synthesis of 2D MoS2 and opens new avenues for its application in advanced sensing and electronic devices.