Abstract

 The efficient synthesis of two-dimensional molybdenum disulfide (2D MoS_​2) at low temperatures is essential for use in flexible devices. In this study, 2D MoS_​2 was grown directly at a low temperature of 200 °C on both hard (SiO_​2) and soft substrates (polyimide (PI)) using chemical vapor deposition (CVD) with Mo(CO)_​6 and H_​2S. We investigated the effect of the growth temperature and Mo concentration on the layered growth by Raman spectroscopy and microscopy. 2D MoS_​2 was grown by using low Mo concentration at a low temperature. Through optical microscopy, Raman spectroscopy, X-ray photoemission spectroscopy, photoluminescence, and transmission electron microscopy measurements, MoS_​2 produced by low-temperature CVD was determined to possess a layered structure with good uniformity, stoichiometry, and a controllable number of layers. Furthermore, we demonstrated the realization of a 2D MoS_​2-based flexible gas sensor on a PI substrate without any transfer processes, with competitive sensor performance and mechanical durability at room temperature. This fabrication process has potential for burgeoning flexible and wearable nanotechnology applications.